Thursday, October 20, 2016

Delays, Frustration, Mysteries and successes… all in a week!

Wow, where to begin? First, the domestic C72 engine overhaul that was moving along nicely hit a roadblock when I discovered that I didn’t have a 250cc head gasket in stock. A quick check of eBay showed a couple of promising possibilities so I ordered one from one seller and a backup from a second seller.
First response was “I am sending two gaskets, as the OEM one has some cracks along the camchain opening area and the second one is good and flat, but is aftermarket and has some rust on the fire rings.” Those came in first and I elected not to use either one of them. The second one should have been in a day later, normally, however the tracking showed that it was sent to San Diego central office and then mis-sent to another part of the city. They finally realized the problem and sent it back to the central depot, which then sent it out to Spring Valley office. It was floating around San Diego for 5 days, including the Columbus Day holiday this year.

When it finally arrived, I hurried to open the package only to discover that the head gasket was an OEM part that fits a 305cc engine! I fired off a note to the seller, who failed to reply the first day, and then asked for more information about the gasket. After a long-winded explanation of the fact that he had listed a 268 code gasket (250cc) and shipped a 275 code (305cc) gasket instead, he came back to say that only MrHonda and a few others would know the difference; then asked why Honda would make two different gaskets for those engines!?!?!? After two more explanations about Engine Building 101 and how the fire rings needed to be close to the edge of the cylinder bore, but not within it, he finally said he would send “another one.” I mentioned that it better be a 55mm bore size and not the 61mm that I had just received and there was no active response, however a correct 268 code gasket did show up a few days later, along with another eBay purchased “backup” gasket from a seller in the Mid-West.

Once the correct gasket was obtained, another hour or two was spent on installing the cylinder head, setting the cam timing, torquing the cylinder head bolts and adding on the rest of the external accessories. Finally it is finished, but a good two weeks beyond what it could have been had the correct parts come in as requested.

Back on the XL200 bike revival, the engine proved hard to start again, even though I had it fired up with a new CDI box and other bits. The spark kept disappearing and reappearing which proved maddening after awhile. A secondary sweep of the wiring connections proved useful as there was a lone black/white tracer wire (ignition) which was found unplugged down near the steering head, all by itself. With that wire reconnected the bike fired back up on a couple of kicks and made a successful lap around the block with no issues. I finished attaching all the rest of the battered bodywork onto the chassis and it awaits a new home now. Even at $600, there seems to be little interest in it so far, but local desert season is about to come upon us, here in SoCal, so hopefully someone will snap it up for a beater bike soon.

The CL/S90 Hybrid bike was stalled out due to lack of a decent exhaust system for the early style cylinder head with the 45 degree angled exhaust port. I finally spotted an inexpensive CT90 head on eBay and bought it up for $35 including freight. It took a couple of hours of cleaning out/off the dirt and baked-on grease and oil deposits, but the valves lapped in okay and all the port configurations were just what I needed. The swap over took less than an hour and finally I had a cylinder head that would take the stock CL90 exhaust pipe that I had obtained from my friend Ron Smith. It still lacks a heat shield, but it otherwise bolted up as designed and offers a nice muted exhaust note. Interestingly enough the carburetor which was mounted on the early-style “twisted” intake manifold was a direct bolt-on to the center-mounted CL90 intake manifold, so that saved some time and effort. The CL90 carb that came with the chassis needs rebuilding, but could be pressed into service if needed. The engine fired up okay and then in the middle of warming up, just quit suddenly. The last time this happened the intake valve had a small metal fragment lodged in the seat, but this time the compression was still good. What was lacking, suddenly, was spark at the plug (a common theme lately). Checking power from the coil to the ignition points plate showed power at the connector but then not at the point wire. Wiggling and jiggling finally did something to power up the wire again and the bike restarted successfully. Unfortunately, the ignition coil and condenser are mounted atop of the engine cases, which are covered by the frame when the engine is installed. Trying to check for connections and/or a bad condenser pretty much requires an engine pull. For the moment, the bike continues to run okay, though.

Another case of spark/no spark is currently bedeviling me with the little C110 Sport Cub. There was no spark initially, so the points and condenser were swapped out. The coil seemed to check out okay with no visible issues. The wiring diagram shows the white with green striped wire that comes off of the ignition coil tying into the condenser along with the other primary coil wires beneath the flywheel.  The wire on this bike was tied to the ground end of the lighting coil instead! This didn’t seem to make sense to me, whatsoever, so I moved the wire off the lighting coil and onto the condenser junction as shown in the wiring diagrams. As with so many other Honda production runs, there were changes at different stages and two different manufacturers were used to supply ignition systems for the little Cub models.

You would think that the C100 and C110 Cub models would use the same components in their magnetos, but that doesn’t seem to be the case and the Nippon-Denso vs. Hitachi component options further clouded the picture. At one stage, I was able to get a strong spark at the end of the coil wire, but it vanished when a spark plug cap was attached.  After that, the spark disappeared completely, once again. More components are on order to see if I can finally track down the source of the voltage leaks or lack of generation of said high voltages.

A few days ago, another friend brought by a 1995 CBR900RR Sport bike which had only 2,000 miles showing on the odometer. The bike was bought at an auction in as-is condition with some rust in the fuel tank, old gasoline in the carbs and general neglect throughout. At first the carbs were brought over for cleaning, which turned out to be less of a nightmare than imagined. My friend took over the fuel tank clean up, which went horribly wrong as he proceeded with the task. After an initial acid wash, he decided to rinse the tank with water which was not fully removed afterwards. The petcock is held on a large bottom tube with a large threaded nut holding it in place. Apparently the nut was over-tightened and broke away from the petcock body.
He thought that the fuel pump was not working and bought an aftermarket replacement, which pumped like crazy and picked up the remaining water and some spare gasoline and flooded the carburetors in the process. Gasoline was coming up the carburetor vent hoses and spilling into the intake ports in large quantities. Finally, he called and asked to bring the whole bike over for me to inspect and repair.

The fuel tank was drained and left to dry in the hot sun, as-is. A new petcock, fuel lines and fuel filters were ordered, which took a bad turn when two of the three lines were reported as NLA/discontinued by Honda. One hose was tracked down on eBay and shipped in, while one of the remaining hoses was repurposed to complete the necessary connections. When the fuel tank was hooked up a jumper wire was used to prod the fuel pump into life. It responded well and proceeded to do a repeat of the carb overflow syndrome. At the same time, the new battery suddenly went from 12 volts down to 3 volts cranking, so it came back off for an over-night charging session.

The carbs came back off, fuel was siphoned from the intake ports and the emission vacuum lines/hoses were all double-checked for correct routing after the carb bowls were inspected for any signs of float valve failures. Everything seemed normal and after some rechecks on the hoses, the system was reconnected once again. This time the engine fired up with no excess fuel leaks and the engine sounded good as it ran off the jumpered fuel pump connection. Supposedly, these bikes will run the fuel pump for a few seconds, then shut down until the engine is up and running. This isn’t sufficient time to refill empty fuel bowls, even when the system works as it should. In this case, the pump wouldn’t run without the jumper wire on the fuel-cut relay connector, however once the bike was fueled and running I pulled the jumper wire and substituted the fuel-cut relay and heard the pump take off and run again. I had forgotten to turn the petcock back to RESERVE from OFF, so the pump was working hard at delivering nothing, until the petcock was switched back to Reserve. The pump refilled the carburetors then settled down to a slow and even click every few seconds, apparently as designed. So the $75 fuel cut relay purchase, which had been contemplated, proved to be unnecessary in the end.

So that’s been my week…   I hope yours was less eventful and more productive overall.


Sunday, October 9, 2016

Two out of three; vintage Honda bikes are runners now…

The S/CL90 project bike had gotten to a running state now, but not without more headaches along the way. Unable to find a decent point plate set quickly, a careful disassembly and cleaning of the old point plate eventually yielded a functioning unit.  The slide throttle parts didn’t seem to agree with the a/m cafĂ© handlebars being used, so the old Wassel-type twist throttle was cleaned up and reused with a shortened throttle cable.
When the first attempts to kickstart the bike were made, the clutch slipped endlessly. Off with the clutch cover, checked the clutch assembly and found nothing wrong, however when the locking washer was installed below the clutch retaining nut, the outer edges of the washer pushed up against the inner edges of the clutch hub and released it every time the nut was tightened down. The immediate cure was to leave the locking washer off and tighten the nut real snugly. Once that was remedied, the engine would kick-over but still not start.
Checking the points with a test light revealed that the point wire was somehow grounding out all the time, so that was repositioned and spark returned to the plug. The next attempt at starting the engine met with limited success as soon as the engine lit off, oil started pouring out of the clutch cover gasket. The early engines have specific gaskets which I had ordered specifically for this installation, however the oil flow slot was a little too large and there was a gap at one corner allowing the oil to come bleeding out relentlessly. At least I knew that the oil pump was working well!
Some RTV in the gasket slot, left for a few hours seemed to mend the problem and the bike restarted, warmed up with no further leaks and then suddenly shut down completely. Repeated kicking did nothing for it and the plug was rechecked for spark which it had and there was fuel in the carb bowl…. So what now!!??
Checking the compression, I discovered that the readings had dropped from around 140 psi to 60psi all of a sudden. That is a good reason for the bike to quit and not restart again… So, off with its head! Somehow a tiny fragment of aluminum had gotten sucked into the intake and lit right on the edge of the intake valve seat, propping it open which caused the compression loss. Removing the tiny piece of material, reseating the valve and reinstalling the head made it all back to normal once again. Bike starts and runs well, shifts gears, stops and just needs a proper exhaust system.
The big problem for this S90/CL90 marriage is that the early S90 engines have a twisted intake manifold and a diagonal bolt pattern in the head for the manifold mounting. Additionally, the exhaust port is on a 45 degree angle vs. the later 90 degree angle for CL90 exhausts and later S90 applications. The S90 came with a short upswept aftermarket pipe and tiny rusted muffler. In order for the CL90 muffler to work on this application either the head has to be changed to the later style unit or the exhaust pipe needs to be cut and re-welded again to achieve the correct exhaust port angle. For the moment, it sits as it is while work continued on both the C72 engine overhaul and the “free” XL200 Enduro Honda which had received a new piston/rebore recently.
The XL200 engine installation went badly, at first; due to misuse of the two top engine mount bolt spacers. Swapping the spacers, which have different lengths, made the engine bolt holes all mis-aligned and it took stepping away from the bike overnight to reconsider the problem, which was pretty obvious once all the facts were considered. Swapping the spacers made the engine bolt installation easy and parts continued to be reinstalled as the afternoon progressed. Once the electrics were all connected, the engine was kicked over to check for spark… and none was noted. These engines have a CDI ignition and the spark can be hard to see in broad daylight. Even so, nothing seemed to be happening so time was taken to consult various forums and U-Tube videos trying to come up with some troubleshooting steps that were appropriate. There was voltage coming up from the stator to the CDI and readings on the coil and pulse generator seemed to be okay. CDI modules were somewhat suspect back in the early days of the technology so perhaps mine was fried. A quick check on eBay found a whole wiring harness with a CDI box attached for $40 delivered, so I took a chance that this might solve the problem. The parts came in just 2 days, but swapping in the CDI box didn’t seem to have a positive effect.
In my research, I discovered that the KILL switch is actually a continuity switch and not one used to ground out the system. The switch knob was stuck in ON position due to years of sitting outside. I was able to remove it, disassemble the contact parts, clean everything and reassemble it successfully. Once the switch was reinstalled into the system, I checked for spark once again. It is difficult to do on these bikes, as they are kickstart only and holding the plug against the head while kicking it over is a difficult chore. I wasn’t sure if there was spark or not, so I put my finger down between the plug and the head and kicked it over again…. ZING! Bingo, we HAVE SPARK now!  The KILL switch was probably all that was wrong in the first place, but that’s how we learn these things, isn’t it?
With the fuel system ready to run, spark at the plug and good compression, it should have started right up, but there seemed to be some problems getting fuel to the plug, so a little gas priming was done from the fuel bowl after the idle jet was rechecked for being clean and clear. In checking, I did discover that the two carburetor nuts were finger-tight so those were snugged up! SOMETHING worked; as the bike finally came to life after numerous more stout kicks and it settled down to a nice idle fairly quickly.  
With a live engine being fully realized, I cut a new drive chain for the bike and adjusted it up with the snail-type adjusters on the rear axle.  Once that was installed, the bike was ready for the “trip around the block” run to see if the clutch was stuck or other maladies would become apparent.  Surprisingly, the transmission dropped into 1st gear and off I went, progressing up through each gear cleanly and smoothly. Even the speedometer was working! The only problem was that at the end of the test drive the bike wouldn’t shut OFF! Turning the ignition switch to OFF and the KILL switch to OFF did nothing to shut the engine down. I quickly removed the headlight bulb assembly and found the KILL switch wiring harness. Plugging the loose GREEN wire into a nearby GREEN wiring double connector finally killed the engine. Problem solved… or not! When I tried to restart the engine, it wouldn’t fire again until I unplugged the green wire. When I tried plugging the green wire into an adjacent double green wire connector, the engine would KILL if the KILL switch was turned to OFF, but only the KILL switch would kill the engine. The ignition switch didn’t affect it whatsoever. I think I better stay with the older bikes, where I can see and measure what is going in and out of the electrical system more easily.

The last bike on the list is the C110 Honda Sports Cub, which has a simple magneto ignition system, low compression pushrod engine and weighs next to nothing compared to the other two machines.