Casa del Honda is a busy place….

 Now that my broken thumb is mostly on the mend, I have been taking in some repair work a little at a time.

This month, two CL77s were in, plus the little CB200T was sold. Now a new challenge has arrived in the form of another SL90 (check old stories for the first oddball version) and as well as a restored CB92 with subtle carb problems. Oh, then there is the sad, but promising 1965 CB77 project recently acquired.

First, the little CB200T with the broken camshaft found a new home in Oceanside, CA about 70 miles away and circumstances created me having to deliver it for a $100 fee. Between replacing the camshaft and the starter switch, and a new front rim/tire. The bike mostly sat in the garage due to the hand injury.

Once the 200T was out of the way, one of my clients who had purchased a 1967 CL77 from an earlier client, brought it back as the spark timing wasn’t returning properly. It would require a cam sprocket replacement, which can be done with the engine still in the chassis, but it isn’t an easy task, The ultimate reason for replacement was that the spark advance return spring was missing! It took several hours to complete the task, but now the engine idle problems are solved. Now, the customer wants the transmission gears X’d and that will be a full engine pull, bottom end tear-down and replacement of the usual parts, including the low gear bushing, no doubt. That one is on HOLD for now.

The next CL77 project came back to me, as the customer reminded me that I had rebuilt the engine when I lived in San Clemente, back in the 1996-2001 era! For some reason, I installed a S12 337cc kit, which now gives 200psi compression readings. The bike was being prepped for sale, and has been mostly revived and repainted. It even still has the old Probe electronic ignition system in place, but needed a full carb cleaning, petcock cleaning, and overall tuning and service work. I couldn’t even pull the clutch lever in due to heavy clutch springs that Honda had specified in later years. Those got tossed and replaced with normal springs, used in CB77s, then the clutch adjuster was replaced with one of the new CMSNL reproduction units. Now I can pull the clutch lever in normally.

                                                             AHMC factory photo-CL77

Then, the rogue CB77 that was offered to me back when I had a broken hand and was recovering from the Hawk GT650 crash. The bike was abandoned with a friend of a friend of a friend, but did have a clean CA title on non-op status. It had been sitting outdoors, about a mile from the ocean for a couple of years, and was covered in rust and corrosion. With a healed hand, I chased down the players involved and was able to pick it up when I was already in N. County for a chiropractor appointment, which is 40 miles from home.

                                                               AHMC factory photo-CB77

There is a separate story on the CB77, which at least did turn over and gave the impression that it had been operated in the last few years. I serviced the carbs, recharged the supplied battery and the bike actually fired up and sounded pretty healthy. The over-sized tires were replaced and some fenders acquired to replace the missing ones. The “cafe” handlebars are being replaced with OEM style flat bars and lots of de-rusting will be in the work flow. UPDATE: Sold to an enthusiast in AZ.

Update on the latest SL90 engine project: It took about 3 hours to full disassemble this relatively simple engine. The whole engine was covered in scale and rust to start with and there were non-standard copper washers under the cylinder head nuts. The point cover screws were rusted in place, so needed the use of an impact driver just to access the point plate, which was also corroded. The camshaft had a non-standard looking set of lobes and the valve springs appeared to be some kind of heavy duty racing parts.

Once the cylinder head was removed a GIANT high-dome piston was revealed inside the cylinder. The piston had a groove cutaway on the side to allow for clearance on the spark plug tip. Once the cylinder was removed, it was apparent that this was the biggest 90 piston allowed at 55mm. The bottom of the cylinder wall was 1mm thick. The piston had no signs of actually being used or run in as there was no trace of carbon on the crown. The engine had been sitting with the piston at near TDC, so some rust had formed below it on the bottom of the liner. When engines sit outdoors, untouched for years at a time, whatever oil that was on any parts above the oil level runs off exposing raw steel to the atmosphere inside the crankcases. With changes to temperatures and weather conditions, the air space condenses moisture into water droplets which attach to the exposed steel parts and the rust process develops.

With the top end removed, I attempted to remove the clutch cover screws, using my tried and true vintage impact driver, using various sized hammers. Basically, none of them would budge in spite of repeated blows. The only way to remove them was to use a chisel and notch the edges of the screws, then work on the edges with the chisel and hammer with repeated blows. Slowly, each one finally gave up their grip on the case threads and finally backed out for removal. It took 1 to 2 minutes per screw to remove the clutch cover, only to discover that the asbestos cover gasket was coated with sealant. So obviously someone had been in there previously. In fact, the little cover over the end of the clutch release plate only had one screw instead of two and the screw type was incorrect.

The shift drum detent plate screw was glued in place as well, requiring more demolition work for extraction. Every inside screw needed the same hammer and chisel effort for removal. With the cases split there were rust spots on the outer edges of the crankshaft, near the connecting rod. Only the transmission gears had escaped the rust attacks.

At this point, several options are under consideration. First, just find a decent used engine and start over again, using the old engine cases. Second, replace the monster piston with probably a 12:1 compression rating down to a normal S90 piston and cylinder. The camshaft profile may or may not work as an upgrade to the stock cam. In any case, I have more than 3 hours of pretty intense labor just disassembling this engine and am left with a pile of rusty and corroded parts to show for it.

BTW the carburetor and manifold which had water damage inside the bowl, still had the stock jetting, which never would have worked on the engine combination that was assembled. The cylinder head did show some signs of port work, but it is apparent that the project never reached fruition.

Fortunately, I went onto a S90/CL90/SL90 Facebook forum and saw some engines for sale in Louisana. That lead to a conversation with the owner who is closing out his collection of bikes and parts, including a nice CL90 engine and a whole SL90 engine. He’s willing to ship them to SoCal once we determine which option is the best. It does take a village to get some of these old bikes back into service once again.

AHMC factory photo-SL90

UPDATE:

I received a mostly intact CL90 engine from my friend in LA, nicely boxed in a reinforced plastic container. After I extracted it from the mound of peanut packing, the disassembly began. To my surprise, the top end contained a recently re-bored to .25mm piston and cylinder, all in great shape. The disassembly of the cases followed the same path as the first one. All the case screws were seized up in their threads and required repeated blows from a big hammer and chisel to break the thread bonds loose for removal. There are 9 screws in the center cases and it took several minutes per screw to extract each one.

Once the case screws were removed, the case halves were separated carefully and the transmission gears and crankshaft were extracted. Overall, the transmission gears were in fine condition. Again, because of sitting somewhere moist for many years the outside of the shift forks had a fine layer of rust buildup. A combination of rust removal and a wire brush cleaned them up for re-use. The inner cheeks of the crankshaft were also freckled with surface rust and were also cleaned with similar results.

Starting with the newly vapor blasted engine cases, I removed the existing transmission bearings which had been contaminated with vapor blast media and swapped them with the CL90 bearings. A new seal was installed in the left case half and reassembly of the transmission and shift fork unit was performed. The crankshaft was installed in the left case and a new gasket laid down. Gently the cases were reassembled but the kickstarter gear engagement with the transmission caused some difficulty, until the engagement was completed by turning the kickstarter shaft slightly and pushing the cases back together again. I had a set of leftover new case screws available from the last engine build, so was able to snug the cases together.

The next step was to disassemble the cylinder head and clean the valves. Another trip to the vapor blast shop had it looking fresh again, along with the cylinder which was stripped of the original black paint. The cylinder was taped up for a fresh coat of paint. The cleaned up valves, which showed nice seating patterns were reinstalled. On the 90 engine the intake valve was fitted with a small valve stem seal. The head was reassembled and then the rest of the engine began the assembly process.

The engine cases go together but with some tricky business to get the kickstarter shaft and gears to nest into each other so the cases will fit up properly. All the transmission gears were in good shape. The camchain tensioner roller needed to be replaced, but the rest of it slowly found its way back together again.

The SL90 carburetor is pretty unique and all the carb kits that were offered were of the S/CL90 style float valve which is not used on the SL90 engine. After some research, I found that the carb kits for the XL/SL70 used the same float valve, so that finally solved the problem. The float bowl was plastered with JB Weld and after being vapor blasted, a hole was found in the bottom of the bowl. More JB-Weld was employed to help seal it all up again.

You have to remember to install the camsprocket on the chain before you put the cylinder head back on the motor. It’s all a little puzzle of parts that go back together in a specific sequence. I discovered that the rubber packing gasket B came in two types with the aftermarket kit. When I had filled the engine with oil, a leak was discovered coming out of the camchain chamber and around this gasket. The chamber area is not a rectangular shape, but bows out on the outside. I wound up using the piece that was in the engine previously that had the correct shape to prevent any oil leaks.

Fortunately, the replacement cylinder and piston were ready to install after a bit of cleaning. It’s hard to find shops that will do boring of small displacement engines here in San Diego, so we saved time and money with the Louisana CL90 motor. Tearing two of these motors down to make one takes a good bit of time and effort, but it is looking good for installation now.

Bill Silver aka MrHonda www.vintagehonda.com

PS

I’m finding that those green “non-asbestos” gaskets from Thailand and elsewhere are seeping oil out of the gasket material. Am I the only one that has noticed this problem?

The 1973 CB350 has an Un-Fourtunate twist

 A referral from another customer, dating back a few years, lead the owner’s of a 25k mile CB350F to my door, owing to poor performance issues. Initial compression readings were in the 120 psi range, except for #3 cylinder which measured 80 psi! The bike was picked up from a local auction company and was in somewhat sad original condition. After purchase, the bike was disassembled and the chassis powdercoated. A tapered steering head bearing kit was installed and lots of work was done to brighten up the engine surfaces. The oil pan was leaking, the valve cover was leaking and the oil pump was leaking oil, and those issues were remedied before it came to me

Day 1

The first thing I did was to remove the spark plug cap and measure the resistance value. Typically, you want spark plug caps to read out less than 5k ohms. This one measured 11.5k ohms. High resistance spark plug caps are a leading cause of poor performance due to weak spark at the plugs. So, first thing on the list was a set of plug caps. Carb kits were installed, but apparently only the float valves and jets were replaced. My experience that in these days, stock #75 main jets are a bit too lean, especially when using today’s E10 alcohol gasoline. In the past I have installed #78 or #80 main jets with good results.

After the owner’s departed, I proceeded to remove the air box and the carburetor rack, plus the coil set from the frame. I was warned that the #4 cylinder spark plug threads were damaged and was shown a spark plug that had rounded off threads, but just way at the end in the first few threads. I have a thread chaser tool to help clean up the threads, so spent some time in working it down into the head to attempt to clean up the threads. The hole was pretty badly damaged, so may need an insert installed. The bike was dropped off around 7pm, so I concluded my work for the evening, but was noticing that the valve clearances seemed to be very tight, so the next step is to check and adjust the valves, then do another compression test, followed by a leakdown test to see where the low cylinder pressure is being lost.

Day 2

The compression readings went up to 150/150/150/120. The head was determined to be a write-off, so another one was purchased from an eBay seller. It supposedly had only 14k miles on it, but there was a considerable amount of carbon build-up on the back sides of the valves. Valves were all removed, cleaned and new stem seals added. The combustion chambers were somewhat carboned-up, so they were all cleaned out with a rotary wire brush. Once everything looked good, the head was reinstalled onto the cylinders with new gaskets and seals. After torquing the head down, the rocker arm cover was installed, valves adjusted and new spark plugs installed.

The carb “cleaning” was apparently from some months ago, so even though the engine fired up on full choke, it wouldn’t run off-idle properly. Off came the carbs again and this time all the idle jets were checked and all found to be plugged up. Not only that, the emulsion tubes were all plugged up with old fuel deposits, so the fueling was completely out of whack.With #78 jets installed and the emulstion tubes and idle jets cleaned out, the carbs began to work normally. I spent over 6 hours in one day, cleaning and installing all the bits and pieces.

Day 3

The bike came in with some older Ram-Flow 2into2 mufflers, which were trashed. The owner’s had rounded up a set of “new” OEM 333 code 4nto4 mufflers, but reported having difficulties with the #3 muffler which was twisted about 10 degrees from vertical and was about a 1/4” off at the inter-connectors that balance the exhaust chambers together. In addition when the two mufflers were installed on the bracket, the header pipe flanges were not parallel to each other.

Installing each muffler in the cylinder head highlighted the fact that the #3 muffler was incorrectly welded onto the header pipe at the factory. Carefully cutting the weld away from the header pipe and muffler, allowed the muffler to align up with the #4 pipe connection and mount up up the rear braket properly. The system was installed again, so that the header pipe could be marked for a re-weld.

I hauled the muffler down to a local automobile muffler shop who had reworked my Jaguar XK8 mufflers about 5 years ago. I was able to hold it just right for long enough to get a tack weld done. I rechecked the marks and gave him the green light to weld it all up again. The muffler was remounted on the bracket and everything lined up as originally designed.

The customer came by with the repainted fuel tank, which was installed and fuel turned onto the carbs. The bike fires up quickly and sounds like a 350 Four should sound with the original mufflers installed. There was, of course, more difficulties with the tank. First, there were remnants of rust and corrosion left inside and secondly the petcock lever required two hands to move from one position to the other.

After the tank was drained so the petcock could be serviced, it was noted that the 4-hole gasket was kind of out of index. The gasket was new, but something was causing excessive drag. The lever face was cleaned up and reassembled, but the problem remained. In the third round of inspection, a second wave washer came loose from the other! Apparently, the old gasket was leaking, so the additional washer was added in an attempt to seal the leak! Removal of the second washer resolved the petcock lever issue, at last.

The bike got a quick test ride locally, as it doesn’t have any license plate. It pulled up to redline in third gear and was running happily now. These bikes were never particularly fast, but are relatively comfortable as a beginner bike with a smooth motor.

Bill Silver

aka MrHonda

www.vintagehonda.com

Dream Carb Dilemma Solved...

From many posts I see on the various forums, many concern the correct carburetor adjustments and settings on the CA77 305 Dream model.

                                    

Both the 250cc and 305 models use the same 22mm carburetor body with just different jets. The main settings for the common CA77 are a #35 idle jet and #120 main jet. Float level setting is 26.5mm for both models.

What seems to be occurring is that the carb kits from the Keyster company are coming in with #40 idle jets and #130 main jets, along with a poor copy of the slide needle. OEM needles will have a K#### number stamped just below the last needle clip groove.

K22402 is the needle for the 250 Dream carburetor. 16151-259-004 is the 250 needle part number

K22401 is the needle for the 305 Dream carburetor 16151-266-004 is the 305 needle part number.

The dimensions of the float valve and needle from the Keyster kits often differ from the OEM parts. The needle length and depth of the float valve seat can vary as well, causing problems with properly setting the float level.

Recently, I was trying to assist a Dream forum member who was having problems with fuel-fouling the spark plugs in just minutes. I ran the whole set of specs by him and offered other possible solutions, but the problem didn’t go away with any of his repair attempts. I happened to have what was basically an unused CA77 carburetor that came with a batch of other loose 250-305 parts. I offered it to him for sale and he eagerly made the purchase. A few days later, with both carbs in his hand, he began to compare parts and specifications. His old carb had a #40 idle jet installed, which was obviously a kit part. In comparing his old jets with the ones from the new OEM carb he determined that using some guitar strings to clean out the idle jets, the #40 in his carb would allow a .027” wire to pass through the hole.

The Keihin jets are metric-sized, so a #35 idle jet is .35mm or about .013”. So his #40 stamped idle jet was actually about a #70 size instead. Bingo! In all of his work and worry about why his bike was running so rich and kept fouling plugs, it was an over-sized pilot jet as the main culprit.

As I guided him through the carb inspection and settings process, he asked if the float valve needle was supposed to be compressed when the float level gauge was used to determine the correct height. That was incorrect! As shown in the Honda shop manual drawings and descriptions, the float height is determined by allowing the float tang to just rest on the spring-loaded tip of the float valve needle NOT compressing it. Compressing the needle will give an inaccurate float level setting and cause performance issues.

                                                        Factory Shop manual illustration

He sent photos comparing the OEM and the Keyster kit float needles and they are markedly different in size and shape. I have found that the needle seat depths are different than the OEM parts and in some cases the whole height of the float valve seat is different than the stock parts. These vital part dimensions often lead to having the floats banging up against the roof of the float chamber when the float height is set with these inaccurately sized parts.

Factory Shop manual illustration

The kit needles are often incorrectly made. My friend, Ed Moore, said that the Keyster carb needles for the CB77 kits actually work well on CL77 carb applications. When used on CB77 engines, they tend to run rich,, causing plug fouling or just poor part throttle performance. Unfortunately, there are few remaining companies that provide carb kits for 60 year old Honda motorcycles, however, the ones being produced have had the same problems for the last 20 years. I have had to use a paper punch to notch the float bowl gaskets on the square bowl carburetors because the material was stamped too wide and the gaskets flip up against the two guide posts on the front straight side of the carburetor bodies.

In cases where air filters have been changed to a different type or just left off completely, the fuel metering will be insufficient, so an increase will need to be made on the main jet. The same can be said for a change in the exhaust system where aftermarket mufflers are used in place of the OEM originals. At times, the needle clip position will have to be changed in order to smooth out the transition period from idle to mid-throttle positions. You have to test ride and make determinations about what the engine actually wants, once you have deviated from OEM intake and exhaust systems. Raising the choke slowly when the engine is struggling will be a helpful indicator to determine that the engine is running lean at part throttle.

When you are tuning up any of the 250-305 engines, knowing the stock specs and settings is crucial as a starting point for further adjustments. For Dreams, it is #35/#120 jet combo that is the starting point. Of course, erratic ignition timing and air leaks at the flange and insulators can cause upsets with the stock settings.

07/25

Bill Silver aka MrHonda

www.vintagehonda.com

1975 CB200T-roubles X2

Just when things quieted down, just a bit, a new rescue opportunity presented itself online…

They always look better in the pictures, but this low-mileage Orange CB200T had suffered a catastrophic failure, which I had never seen or heard of before. I found the post, somewhat by accident on OfferUP classifieds, and it was located in Pacific Beach area, about 25 miles from me. The post showed about 8 photos, including the one where the end of the camshaft had broken away from the camshaft body. In person, the bike was suffering from the usual 50-year-old chrome pitting and alloy corrosion, not to mention that it was just pretty dirty from sitting somewhere exposed for a good part of its life.

One can only imagine what would cause such an unusual failure of such a sturdy Honda part. I couldn’t even guess at the cause, unless someone had tried to over-tighten the spark advancer bolt on the end of the camshaft and somehow broke it off in the effort.

The owner, Corey, had purchased the bike for basically market prices for a running, titled and registered 1975 Honda street bike. When I went to have a look and purchase it, he said that he was riding it back from a fresh purchase and somewhere along the return ride, it just went Bang! And that was the end of that. He admitted that he wasn’t much of a mechanic, but tried to figure out some possibilities on his own, including replacing the ignition coil, which was valid as the plug wire was broken at the coil case and attempted a few more things, until he checked the points and found the end of the cam was broken off.

We loaded it up into the Tacoma and off I went on a new, puzzling adventure with a little CB200T, which was the final successor to the line of 160-175 from the mid-1960s to the early 1970s. Honda had reworked the engine with larger wrist pin sizes for the pistons and rods, plus created some rubber intake manifolds to reduce some of the shaking and quaking of a 200cc engine with a 360-degree firing crankshaft design.

I offloaded the bike in the driveway and started peeling parts off of the chassis. I was quite surprised to find that not only did the footpegs have thick rubbers, but the whole footpeg and sidestand assembly was rubber-cushioned where it bolted to the frame. The engine’s OEM carbs were disassembled in a box and a pair of shiny new Chinese copy carbs tucked into their places. The Chinese versions of replacement carbs only goes so far, as they chose to put two right-side carburetors together as a set, instead of replacing the normal left and right oriented carburetor configurations. Using two right side carbs puts the left side carb adjustment screws inboard between the pair, as well as causing the left side fuel hose to exit on the left and then snake around to meet up with the petcock on the right side of the fuel tank.

I proceeded to remove the side covers, air box covers, air filters, which are fitted with the rubber connector tubes to the carburetors, all in one piece. One of the pluses of the bike was that it still had intact OEM mufflers that hadn’t rotted out on the bottom. Soon, it was time to yank the hefty motor out of the frame and put up on my Work-Mate bench to drain the oil and remove the top end for further inspection.

I have a handy 18v power ratchet which helps buzzing off a lot of long bolts and makes the tasks much quicker. The top cover came off easily, as long as you remember the little 10mm bolt in the front edge. Then, I had to puzzle out how to get the camshaft out of the head. One of the apparent changes from the 175 to the 200 engine was that the 200 now had an endless camchain and a bolt-on cam sprocket, instead of the earlier bikes with a master-link type camchain and pressed-on sprocket. The camshaft is bolted to a removable sprocket with 2 bolts, then you have to pull the rocker arms and shafts, giving clearance around the camshaft area. I dismounted the chain from the cam sprocket after removing the two bolts. Then, it was a matter of snaking the camshaft out of the head and camchain. I tried moving the chain to one side of the camshaft mounting ears and then the other, but it seemed like the cam was a bit too long to just tip it out of the head. The end of the camshaft that is part of the tach drive has a thin, hollow knock pin that connects the tach drive end with the camshaft. Removing the knock pin allowed the camshaft to finally be worked loose from the head.

Next, the cylinder head was lifted off and taken to the workbench. Looking at the colors of the carbon on the valve heads looked like it didn’t have a lot of miles on them, backing up the 5300 miles showing on the speedometer’s odometer. Another change to the 200 engine is the use of long-reach D8EA spark plugs vs the older D8HA plugs with about a 1/2” reach. I used a special tool to clean up the spark plug hole threads, as one side looked a little bit like it had been cross-threaded at some point.

The piston crowns were carboned up, and the ring identifying marks were worn off. When I turned the engine over to allow the pistons to go to the bottom of the stroke, I could see recent honing marks on the cylinder walls that were not factory-made. Lifting the cylinders off revealed the green gasket material used on aftermarket D&K gasket kits from Thailand, so obviously someone had been poking around inside the engine in recent times. The repair history was unknown to Corey, but there was a sticker on the tail light lens that had the name of a shop in SD County. One might infer that whoever had the top end apart and back together again might have failed to tighen up the spark advancer bolt sufficiently and with a few miles driven, the whole thing went sideways in a big way.

Some previous owners had replaced the stock CB77-sized tires (2.75x18 front and 3.00x18 rear) with a 3.00 x 18 front and a 3.50 x18 rear set of IRC tires. Not only that, but the rear shocks were all shiny new and apparently just about a 1/2” longer than the OEM shock lengths. This caused the swing arm to be pushed downwards towards the mufflers, basically preventing chain maintenance or wheel removal without dropping the exhaust pipes down. In one of those odd MrHonda synchronous events in my life, someone had dropped a bunch of misc used parts with me a few years ago. The only part that I thought would never be used was a pair of OEM CB200T rear shocks! I found them, disassembled them for cleaning and reassembled them to use as a replacement for the too-long aftermarket shocks on the bike now.

I popped the wrist pin clips out of the pistons so I could clean off the carbon build-up and remove the rings to check for excessive end gaps in the cylinder bores. For some reason, Honda uses two, seemingly identical piston rings for the top two positions. On most all of Honda’s piston rings, the numbers are marked on the top with a T or oversized mark, but the “scraper” ring only has a 2 mark, as I recall, for placement of the ring in the second piston ring land slot. Unlike most other scraper rings, which have a very decided scraper lip on the bottom edge of the ring, the rings for 175-200s have these mystery rings instead.

So, I ordered a bunch of replacement parts for the little bike, including all new cables, a new battery, new spoke kit, a new front rim (rusted badly), engine gasket kit, while still fishing for a good used camshaft to get this bike back on the road again. Honda made the 200T bikes for 4 years, so you would think that parts might be floating around. There is some use of 200T engines parts for the AHRMA racer group, so I might hit them up. Ironically, right after this bike was posted on OfferUp, another horrible ratty parts bike showed up for $250 asking, which might solve the camshaft problem, but then you wind up with a pile of ratty used parts that no one wants.

Thankfully, a member of one of the two CB200T Facebook groups replied to my pleas and actually turned up a nice, used camshaft with the advancer and sprocket still attached for $60 plus shipping.

More problems arose when I dismantled the front mechanical brake caliper to allow for a cable change. There is a little cone-shaped spring that puts pressure on the plastic disc that helps the brake to be self-adjusting. Of course, the spring was not to be found so the only one listed for sale on eBay was in Thailand.

Someone had listed a front brake cable on eBay, but it looked like a conventional adjustable brake cable seen on most drum-braked vintage Hondas. It was listed as fitting a CB125 and CB200T, plus the CL200 models. Obviously, the two different brakes require different cables and the one arrived as the CL200 version. It was only about $12, anyway, but the seller refunded the money and I kept the cable. Finding the correct cable is kind of difficult and I found a seller in Norway who had one for $40 with free shipping! According to the eBay listing, the seller had sold 155 of them already.

There was a big ugly spot of rust on the front rim, so I found a NOS rim at CMSNL and some spoke kits from Thailand. The next search was to find a 2.75x18 front tire so I could change out the whole rim, spokes and tire at the same time, the use that tire to install on the back wheel to get the tire sizes correct once again.

I had the top end components, including the cylinders, cylinder head, end covers, tappet covers and top cover vapor-blasted by my local friend Jon, who has the whole setup in his busy garage. I’ll scrub up the bottom end as much as possible and the rest will go back together with a shiny top end and patina on the bottom.

The rear fender chrome was pitted in the section beneath the seat, so it was removed and cleaned up. The front fork seals were on the list of repairs, so those were purchased. The intricate boots are NLA, apparently but are not torn at the moment. It is easier to rework the front end when no engine is installed.

Fork seals were replaced and the engine started up successfully. I drove it around the block and down a half mile away from the house. It seemed to be running well, but the petcock, an aftermarket version, was leaking internally. I had to drain the tank and disassemble the petcock to find out what was going on. The back side of the fuel lever was somewhat distorted and running a smooth file across the face revealed the high spots and low spots.

It was all going well, until I checked the headlight bulb, which tested fine. That only left the infamous starter button switch, which was a problem for a number of the mid-1970s models. The handlebar switch also carries the brake cable, brake lever and front brake light switch. I bought a switch from Indonesia that was supposed to be the replacement for the OEM switch but the internal switch function was poorly designed and blew the main fuse out when it was tried. Shockenly, the few new OEM handlbar switches were listed at between $250-300 and all were in Asia somewhere.

After consulting the wiring diagram and looking at the Instant ON headlight function, I decided to rewire the starter solenoid so it used the handlebar switch to ground the circuit, instead of toggling the 12v to the starter solenoid. Using a readily available CB175 switch seemed to be the answer. It won’t have the kill switch function, but will have the option of turning the headlights On/Off manually.

(See the accompanying story about the headlight switch fix)

In the middle of all the repairs and parts ordering, I crashed my 91 NT650 Honda Hawk GT650 and broke my thumb, so doing repair work is challenging to say the least now.

June UPDATE:

The bike engine was repaired, the front rim was replaced with a NOS one and a new tire installed.

The aftermarket petcock kept leaking internally, so a NOS OEM Honda petcock was purchased for about $60. The registration ran out at the end of April, so I titled the bike in my name on PNO status.

I was torn as to whether to keep it around for a local parts chaser bike to sell it as my garage was otherwise full of 305 Super Hawks. I put it up for sale.

In the last few weeks, another CB200T showed up as a customer bike, which had been dead for about 10 years. Pulling the carbs apart for cleaning and inspection revealed that the carb slides had been installed backwards, which caused fuel fouling of the spark plugs and stalling at an idle.

The petcock was incorrect with one fitting instead of two for the carburetors. I replaced it with an aftermarket unit that was correct for the bike. There were LOTS of issues with electrical system components, as all the turn signals and the headlight were converted to LED lights. The handlebars were changed to a lower version and all of the switch wiring had been routed outside of the handlebars instead of through the insides. The fork ears were replaced by aftermarket units which had slid down the fork tubes, which had been painted. The paint cause grounding problems for all of the wires inside the headlight shell. The wiring harness was an aftermarket piece, so sorting out the correct wire colors became an issue.

The mechanical front brake caliper was frozen up inside, so the brake was non-functional. It was disassembled for cleaning and lubrication while a new OEM brake cable was ordered and installed in the same process.

The engine was tuned up with camchain adjustment, valve clearances checked, carbs cleaned and ignition timing reset. The spark advancer was removed and cleaned/lubricated, as well.

With aftermarket handlebars, the cable lengths were a bit off and needed to be routed differently.

The “cafe” look had been accomplished by cutting up an original fuel tank and creating a bump-stop seat! The stock tank had been sealed, but the gas cap was coated with the tank sealer, so a new fuel cap was ordered and replaced. Ultimately, it all came together and was picked up after being in the shop for a couple of weeks. My broken thumb is getting stronger and I can do a lot of mechanical work again, but the hand is still a little weak and sometimes painful.

Anyway, as so often happens to me, not one but TWO unusual bikes showed up during the same month, and they are now back on their wheels and in circulation once again.

Bill Silver aka MrHonda

www.vintagehonda.com

It’s a HOLDUP! What goes up, doesn’t always come down…

After 2 months of healing my broken thumb, due to crashing my lovely Hawk GT650 in March, I was  in the process of winding up the last of the repairs on the bike. The end of the centerstand was folded forwards and when we tried to straighten it out, the metal just folded over. A replacement centerstand was purchased from eBay, but looking at the procedure to replace it, the exhaust muffler needed to be removed to access the pivot bolts.

I have had a Harbor Freight bike lift for at least 6 years and despite its shortcomings, it has usually hoisted bikes up to working height and then let them back down again. This time, it all went wrong as the lift quit pressurizing the horizontal bottle jack used to move the mechanism. The 420 lb bike was sitting on the lift, secured by the safety bar, which can be inserted in 2 locations. The bar can only be released when the lift is pressurized sufficiently to take the weight off of the bar and linkage.

The lift has been acting poorly for awhile, but with enough extra pumps, it has worked to get the bike up to a good working height. It repeated the same pattern, but suddenly, after the repairs were completed to the bike, the lift quit lifting whatsoever. So, the bike was stuck a couple of feet in the air and even trying to use a floor jack on both ends, the bar wouldn’t release. All I could deduce was that the bottle jack needed to be rebuilt, but first it had to be extracted from the bike lift mechanism and bracing. This proved to be a very taxing process, which took more than an hour to maneuver around the bracing and tease out the big mounting bolt using 15/16” wrenches and sockets, then the release mechanism needed to be separated from the framework.

The release linkage is a convoluted set of levers and arms that connect to an articulated shaft, which bolts to the end of the release valve stem. To make it more complicated, they used a double-ended coil spring to keep some tension on the valve. The spring has 90-degree ends turned out from the coil portion, but they are about 180 degrees apart from each end. The ends go into the body of the jack, just outside of the stem and the other end goes into the articulated connector face. This supplies some return pressure on the release stem, so it buffers the release of pressure, preventing sudden drops in the lift mechanism.

Initially, I had to crawl on my stomach and reach in with my broken right thumb and my left hand to tease out the mounting bolt, then separate the release mechanism from both ends. Visibility is limited and not knowing exactly what was involved made separating the parts even more difficult. After an hour of figuring out what was needed to remove the jack and dragging the 15 lb. piece out of the framework, it was finally removed.

The next day I started to call around to see who could rebuild the jack and discovered that NO ONE does that kind of work anymore, at least in San Diego. Finally, someone suggested that I contact Harbor Freight to get some assistance. I went to the local store and was told to go to www.harborfreight.com/parts to find a replacement part. Sure enough, they had the jacks available for $65 plus tax, but with free shipping. The local warehouse is about 100 miles away, so they were able to deliver the jack in 3 days. Then the fun resumed, re-installing the part back into the lift mechanism.

It occurred to me that getting the bike off of the side stand and onto the newly installed centerstand would allow the removal of the back plate which was designed to facilitate rear wheel removal. With the bike strapped to the lift in 4 places, I was able to get a small floor jack under the engine and lift the bike up high enough to deploy the centerstand and let the bike sit squarely on the lift. This allowed the rear access plate to be removed and give a little bit of extra access to the jack installation process.

It’s not an easy task, to be sure. The jack comes with a special roller end to contact the pedal linkage and there is a big spring involved. At one point the pressure plunger popped out and started leaking hydraulic fluid on the ground. The plunger has no internal stopper so it has to be positioned out just enough to get the spring and retainer on the end and the retainer pin installed.

I had to jam 2×4 wood blocks underneath the jack body to get the angles correct to engage the linkage on both ends. The release valve mechanism needed to be rotated fully in one direction in order to insert the spring end into the face of the articulated joint, then secured with a 5mm bolt. After 1.5 hours of wrestling the jack and all of the linkages into place, the deed was done. The bike lift raised itself off the safety bar, which was withdrawn and then the bike was lowered gently back to the bottom stop.

It was a success in the end, but was extremely difficult for a 70-something, one handed senior citizen to accomplish alone. There are probably thousands of HF lifts out there, and at some point they will need the same repairs. BEWARE.. it ain’t easy!

Bill Silver

aka MrHonda

www.vintagehonda.com

The Dream Carb O-ring Dilemma

 When it comes to the CA72-77 Honda Dream carburetors, Honda has perpetuated an error in the size and part number of the flange in their parts books and online part listings.

I have what appeared to be a nearly new Dream carburetor on hand, but the flange o-ring needed replacing. Normally, this isn’t a big deal, however when you look up the part number for the o-ring, you get a 16173-259-004 (Keihin) part number, listed in the 1968 US parts book as a 31mm part. Looking up the part number online gives a 24x2.4 size instead.

Most of Honda’s o-rings of that type are 2.4mm thickness. When I ordered that part number from an eBay seller, which came with the original parts tag, it was woefully too small at 24x2.4. Nosing around the internet, I found 91307-958-003 31.7x2.4 o-ring that is pretty close to what is needed. That part is listed for an ATC185, but searching the part number comes up empty now. 91306-MA6-005,

91305-KRM-840, 91305-KYY-900 all come up now as 31.7x2.4 o-rings currently, when you search by the o-ring size. Also, in the search by size, 09280-32006 came up as a Suzuki part number.

Measuring the o-ring channel on the carburetor gave a measurement closer to 32mm and perhaps 2.7 width. For $12.76 I found I could order 10 o-rings in a 32x2.4 size from China, but obviously, there is a delay in getting them, rather than buying from eBay sellers or Honda dealers.

UPDATE: The Chinese o-rings were offered as OD instead of the commonly used ID sizes. The first batch came in at about 27mm ID. I reordered them with 37mm OD, and they fit perfectly. 

SO, BE AWARE of how o-rings are listed on eBay and other sites. I’ve never heard of o-rings being measured by OD as the primary size previously. 

So, I have ordered a few versions and we’ll see which ones are the best fit, in the end. DO NOT order by what is listed in the parts books and online parts microfiche!

Bill Silver

aka MrHonda

www.vintagehonda.com

The “Fix” for the Honda CB200T headlight-starter switch

The problem: In 1975, DOT ruled that all street bikes must have Always ON headlights.

The function inside the switch was a hot 6/12volt wire from the ignition switch that toggled between the headlight ON function and the electric starter function.

Sadly, the first-generation starter switches were made with a plastic switch case, which failed, probably due to the heat created by the full-time voltage passing through the tiny contacts.

Normally, previous starter solenoids were fed voltage from the ignition switch circuit that used the grounding of the primary windings through the starter switch to complete the energizing of the solenoid. With the 1975-on edict, the solenoid had to ground the primary side of the windings first, then applied the voltage back through the starter button switch.

Early:

BAT-IGN SW-Starter solenoid primary windings and grounded at the starter button contact, grounded to the handlebars

Late: BAT-IN SW-Starter solenoid primary winding which was grounded at the solenoid mount and then voltage was sent through the harness to the central starter switch contact which completed the circuit with voltage fed to the starter switch contact.

The starter solenoid has a 4-wire connection. The large terminals connect the starter and the battery together when the magnetic solenoid plunger is activated by the completion of the primary wires to B+ and ground. The primary windings don’t care which ones are connected to power and ground. On the CB200T solenoid, the short green wire is grounded by a bolt near the solenoid mount.

On pre-1975 bikes, the yellow/red wire normally goes to the handlebar switch and the lead is grounded to the handlebars when the starter button is pushed inwards.

                                                                    

                                                                CB175K3 starter switch, modified 

On later models, the handlebar wire is energized through the voltage in the central starter switch contact when the button is pushed inwards. The solenoid primary is grounded through a green extension lead, which has an eyelet on the end. The green wire is then bolted to the chassis.

Currently, the worldwide supply of model-specific CB200T/CL200T starter switches is down to the extent that any that are listed on the internet have asking prices of $250-300+

                                                   OEM CB200T starter switch 35150-389-671

Solution:

I figured that a late CB175K3 handlebar switch would do the same functions, but without the KILL switch function. The CB175 switch needs to be modified by drilling the threads out where the cable adjuster would normally sit with a 5/16” drill bit. You have to be careful not to drill all the threads out, but leave about ¼ of the threads intact to function as a stop for the non-adjustable disk brake cable end.

To access the wiring harnesses I removed the handlebar clamps and rolled the handlebars backwards onto a thick towel placed on top of the fuel tank. This gives access to the wiring harness leads.

I used a thin piece of wire to wrap around the ends of the old switch as it was withdrawn from the handlebar tubing holes. The wire was then attached to the new switch harness and pulled back through the handlebar holes and out towards the hole at the back side of the headlight shell. The throttle cable as attached and the throttle wire connected to the throttle drum. The CB175 switch has the same locating pin inside the housing to index with the locating hole in the handlebar. The two halves are joined with the two screws to lock the switch in place.

The brake cable is installed next into the switch housing and the brake switch and lever installed. The handlebars are rolled back up to where the index punch marks are even with the split in the handlebar mounts and everything is tightened back down again.

With the switch harness ends tucked back into the headlight shell, the wiring connectors must be color matched to the harness leads. The stock left hand switch had the Hi-Lo functions which are no longer needed. The excess wire ends can be cut off or tucked into the wiring bundle. The Yellow/Red wire from the handlebar switch connects to the matching Yellow/Red wire connector from the main harness. Now the wire is going to ground inside the starter switch, instead of going to B+ voltage. The solenoid green primary wire is removed from the ground bolt and attached to the positive side of the battery.

The handlebar switch leads have to connect back to the harness with the yellow and yellow/white wires connected to the harness connectors. The black/white junction has a male pigtail end that connects to the black power junction. The white, blue and green ground leads from the switch connect to the headight bulb connections. The high beam has two blue wire connections to make the high beam function and to illuminate the high beam indicator light located in the top of the headlight shell. Be sure to connect the front brake light switch leads into the matching connectors inside the headlight shell.

It never hurts to keep a few spare fuses handy, in case some incorrect wiring connections are made. I lucked out and when the key was turned on I had a nice bright green neutral light and functioning front brake light switch. Turning the new handlebar light switch ON to Lo and Hi gave me lights in both positions. Tapping the starter button with the bike in neutral gave a quick click and then the starter engaged as normal.

So, the only cost was the OEM CB175 handlebar switch and an hour or two to install it and make all the wire connections match up. I saved at least $200-250 from avoiding the “proper” CB200T starter switch which had a current retail price of $205, although they are NLA from the usual vintage bike parts sources. If you are faced with a defective starter switch, this is one option that can work for you.

Bill Silver aka MrHonda.

www.vintagehonda.com