Wednesday, May 29, 2019

Honda CB400F... coming in pairs now

With the last Tracy-bodied CB400F acquisition pretty much done (as far as I am going to take it), another low-miles, all stock, red, 1975 CB400F turned up on the local Craigslist posts, although the bike was actually in Temecula, CA. The photos looked promising and seller claimed to have had to buy 3 different exhaust systems before he could cobble together an all-OEM unit. Miles were in the 10k range, so it should be in decent shape overall, at least mechanically.

A friend, Michael, who lives up in OC, had contacted me looking for a nice vintage bike for his buddy to ride. He initially attached a 1969 CB450K2 listing from Craigslist, but it was up in Central CA. The bike looked decent enough but parts for the 450s are getting scarce on the ground and they aren’t my favorite model anyway. After imparting those thoughts, Michael sent back a link to the red 1975 CB400, which had been posted up in OC, after the one in San Diego had expired. Asking price was $4600, including a bunch of spares, including a nice fuel tank. I opined that if the price was closer to $4k, it would be a good deal, all things considered.  Next thing I know the deal was done, apparently at $4k and the bike was brought down to its new home in Mission Viejo. A day or so later, after Michael had taken it out for a test run, he sent back a message stating:

1.  Most important, it has an oil leak, that looks like from the head gasket just under were the pipe connects. Is this simple fix… do we just need to torque the head bolts?
2.       One of the 4 float bowl gas needle valves leaks
3.       The clutch slips a little when pulling high RPMs.

Unfortunately, for many of the inline Fours from the 1970s, the head gaskets tend to leak out around the o-ring seal, where the oil is channeled up from the pump through the cylinders. This is common for 350-400-500-550 and 650 Fours and not unheard of on the SOHC 750s, starting back in 1969. For a mechanic, the good news is that most all of the “small” Fours have enough room around the frame to remove the cylinder head with the engine still in the chassis.

A good webpage overview covering a restoration procedure is

In this case, once the cylinder head is removed, then the “fun” begins…

The valves must be removed and new valve stem seals installed. The head needs to be checked for any high spots or warpage. All the valves and combustion chambers need to be de-carboned and cleaned. Camchain guides and end bumpers should be checked and replaced if needed. All the cylinder head hardware and fasteners must be cleaned and inspected before reuse. Securing the cylinders to the crankcase before any engine rotation has begun can prevent the necessity of pulling the cylinders and scraping off a LOT of factory gasket material from the base of the cylinders and the upper crankcase. Once the cylinders break the gasket bond between the cylinder base and crankcase, you are in for another couple of hours of labor.

After shedding the exhaust system, before mounting the bike on my bike work rack, the rest of the task is just a slow and easy disassembly of the top end components. ONE of the 8mm cylinder head nuts, which are one of two that are exposed to the elements, needed a fork tube slid over the end of my 3/8ths drive ratchet in order to break it loose. When the top cam cover/cylinder head cover was lifted off, I could see remnants of a previous attempt to seal up the cover to the head using some liquid gasket material, instead of just replacing the elongated o-ring packing.

The cam and rocker arms all looked well lubricated, but the tensioner blade on the back was getting some ridges in the face, so was changed.  The valves were taken out one cylinder at a time, de-carboned and the stem seals changed on the inlet side. The gasket kit came with 8 seals, so apparently these early engines only had seals on the inlet side. Checking current parts lists show a different exhaust valve guide part number, which can accept a stem seal, but the cylinder head part number was a 377-000, the original part number to the bike, which takes only 4 seals on the inlet sides.
There was a build-up of soft carbon on the back sides of the intake valves, indicating worn stem seals. Soft carbon deposits covered the combustion chambers and tops of the piston crowns, but the color on the exhaust valves seemed to indicate pretty good burning even with stock jets.

The whole intake system was intact with all the proper clamps and components in place, indicating that the carb rack might never have been off the bike. The carbs came apart without drama and all of the o-rings that seal the main jets and float valves showed definite signs of age. New carb kits were ordered from my friends at, along with a couple of sets of over-sized jets, fork seals, spark plug caps and other repair items needed for the bike. The owner supplied a gasket kit, but it was one of the Athena aftermarket kits, not a more desired OEM Honda kit. Hopefully, the head gasket will withstand the heat and pressure of the engine for the immediate future.

The bike apparently lived much of its life in Wisconsin or somewhere in the Mid-West and there was a general sprinkling of corrosion on the chrome and alloy parts that was consistent with its early days outside of California. Michael wanted the outer engine covers repainted, as they showed signs of corrosion that had worked beneath the original coatings. After the generator side cover was removed, I was surprised to see signs of the rotor rubbing on the inside of the field coil and a bit on the outside too. Given the fixed nature of these components, which never should contact each other, one must assume that the bike was crashed down on the left side and the case deformed enough to allow contact between the rotor and field coil. When the cover was stripped of all the components, it was clear that the cover had been impacted enough to deform the outer edges of the cover casting. This could be a used cover that was installed after the original crash had occurred.

I have been raiding the leftover parts of my friend Scott, who restored a couple of CB400Fs back about 10 years ago. Of all the odd parts that he still had was one NOS CB350-400F rotor! I made a quick 22 mile round-trip on my newly-acquired 2002 Honda Reflex scooter and brought back the prize for installation. The engine was spun over to check for any deformity on the end of the crankshaft, but the rotor runs true with no wobble or run-out.  The dented area of the cover was worked a bit with a big brass drift and checked for any uneven heights of the screw standoffs.  The field coil checked in with 4.5 ohms and the stator windings were all connected to each other, but not to ground, so it should all work well, once the components are all reinstalled. I did notice a different flange nut holding the rectifier onto the frame and closer inspection revealed that the bracket had been re-welded at some point in time.

Checking the forks for weeping seals, it appeared that they had been replaced at least once before and they didn’t seem to be wet when the dust boots were pried up for inspection. What did show up were some fine wear lines on the fork tubes, equal on both sides.  A bit of test riding will be needed to confirm any leaks, but it may not be the fault of the seals in this case.

Michael reported an oil leak beneath the engine on the right side, as well. Apparently the galley plug cap was leaking slightly past the o-ring, so that will be addressed when the clutch cover, on the same side is removed for the clutch inspection and necessary repairs. Later a second galley plug, just behind the oil filter housing was also weeping some oil passed the o-ring. Both were replaced with the desired results.

The clutch cover was removed and the clutch disassembled to check for signs of slipping. I have never had a CB400F that slipped its clutch, even during racing conditions, so wasn’t surprised to find no signs of wear or slipping on the plate sets. The bike came with a complete set of plates and springs, so they were installed anyway. The springs were an optional 323 code spring from the CB500 Fours, so the clutch lever has a bit more tension when disengaging the clutch now. The cover was cleaned and painted, along with installation of a new kickstarter shaft seal.

A new set of exhaust flanges were available from so for a reasonable price, the exhaust system got a bit of extra bling. The exhaust collars had been painted over the old rust, so were stripped again for another coat of high-temperature engine silver.

The carbs were setup with #78 main jets, instead of the stock #75 sized jets, in order to compensate for the alcohol-based fuels we have to use in SoCal. The bike pulled strongly through the gears, once the engine was running again, but the plugs came out on the white side, so a bump up in the jetting to #80s might be in order. Speaking of spark plugs… the original plug caps all showed between 9 and 10k ohms, which is out of spec for resistor caps, which are set at 5k ohms of resistance.

The last stop in this journey was to re-seal the spare fuel tank that came with the bike deal. The tank was straight and the paint in decent condition, but a thin coating of surface rust was seen and felt in the roof of the fuel tank. A flush with phosphoric acid, followed by a rinse and dry preceded the installation of the 2-part Caswell epoxy sealer. A new OEM fuel filter kit was installed after the petcock was disassembled and cleaned.

Riding the bike is a bit of a time travel, as it is about as stock a bike as I have ridden for quite awhile. I bought one new in 1975 and have the muscle memory of that bike still ingrained in my psyche. There is still a bit of a lean stumble at part-throttle, consistent with just about every 350-400 Four that I have ridden, but once it clears that little glitch the engine winds out cleanly and with a pleasant roar from the intake and exhaust muffler. The single piston brake requires a strong pull to haul the bike down from speed, with an assist from the rear drum stopper. They are pleasant bikes with classic café styling that has aged well over the past 44 years.

Wrapping up this revival project would seem to end the 2x2 of the same bike combos that keep coming my way. Next up, not one but at least 2 CB72-77 engines for rebuilding…. One is very “stuck.”
Bill “MrHonda” Silver

Monday, May 27, 2019

A most unusual Honda CB400F… Part 2


There is a whole separate story about the poor shipper who bid on the bike’s shipping costs and got waylaid during his trip, but I will cut to the chase and evaluate what showed up at my residence a week or so later.

The bike was dirty, oily and smelled of gasoline when it arrived. The rims had rust, spokes were dull, the rear brake backing plate was devoid of its factory finish, both fork seals started bleeding oil after arrival and the battery was held in with a bit of copper wire, plus lacked the requisite battery vent tube. Lacking the vent tube, battery acids flew backwards, beneath the bodywork, spraying sulfuric acid on the frame tubing and the rectifier, which is bolted to the frame on that side. The drive chain was dirty and rusty and there were unsightly blemishes in the black paint where apparently a tarp was laid across the bodywork for a few generations.  The master cylinder was drooling a bit of brake fluid and the caliper proved to be packed with decades-old muck, requiring replacement of the seal ring, piston and brake pads. The fuel tank was seeping fuel out of a lengthwise crack that had been unsuccessfully repaired with a layer of fiberglass cloth and resin.  The leak drooled gasoline all over the cylinder head and much of the upper end of the bike, which mixed with old dirt, oil and other contaminants.

It appeared that the engine might have been removed before it was painted satin black, as there wasn’t any noticeable overspray to be seen on the frame mounts. Whatever it was, after 40 years, the paint was no longer staying adhered to the engine components. I was tempted to call the bike “Calico” due to the blotchy spots of paint that remained all over the engine.

Apparently, the Tracy bodywork installation required removal of the side cover anchor bracket on the left side and removal of both of the welded-on seat brackets. Perhaps the mislabeled bike title “1975 CB450” was a clue as to the actual ownership knowledge of the machine. The fuel tank had some kind of silver coating, which was disintegrating rapidly. The petcock appeared to be an aftermarket copy of a dual outlet CB750 SOHC unit, but only one fitting can be used on the single feed CB400F carb sets. An interesting side note is that the big rectangular tail light lens has Suzuki on the edge and appears to be from an early 1980s GS850 or similar model. I finally got the key (copy) in the mail with the title, but the bike only turned over a few times before the battery went dead. It showed 11.75 volts on the bench before connecting the charger to the terminals.  A day later it was showing 13.25 volts, so there was some hope for it.

In the meantime, the 1-piece bodywork was wrestled off the chassis and rolled over to expose some ugly fiberglass work done on the bottom, probably to address fuel leaks there. The tail light wiring was held together with wire nuts and the two bodywork mounting bolts at the rear frame had no nuts attached.

As mentioned previously, the engine had been painted satin black, perhaps 40 years ago, but the paint was peeling off in many areas. The carburetors were fitted with K&N pod filters, instead of the factory air box. There was old gasoline and oil residue all over the top of the engine as well as underneath.

I decided to just pull the carburetors off and disassemble them for cleaning and to see what jetting sizes had been installed. All four carburetor throttle bodies were coated in a brown, slimy coating on the insides, leading to the intake manifolds and inlet ports on the cylinder head.  The intake manifolds appeared to be originals, so new replacements were ordered, along with new carb kits, brake parts, fork seals, spoke kits, a battery strap, spark plugs, tune-up parts and lots more, which ran up a $300 bill at

A lengthy carb strip, cleaning and installation of new o-rings brought the carbs back up to spec and the bike started up and ran cleanly, initially... I was pleased to see that the jets installed were #40 idle jets and #80 main jets. Stock jetting is #40 and #75, so obviously the bike needed extra fueling to compensate for the 4:1 Kerker exhaust and the lack of a proper air box/filter for the intake side. Additional main jet increases may be required due to the CA alcohol infused fuels, which is the only option these days in California. The carb rack is nearly identical to the one used on the CB350F predecessor, which are calibrated with #35 and #75 jetting.

On subsequent restarts the engine would only run on 3 cylinders, leaving #4 with a cold exhaust pipe. The carb rack was removed again and a tiny piece of fluff was found to have gotten into the #4 cylinder’s pilot jet. With carbs reinstalled, the engine fired up sounding healthy once again. While checking for other #4 cylinder possible problem areas, a test of the plug caps found that all of them had between 9k and 10k ohm resistance readings, so they were all replaced with new NGK 5k ohm caps. 

The engine now sounds good with no unusual tapping, clicking or banging around inside. An oil cooler had been fitted to the bike, but 40 year-old oil lines were dripping at the connections. New hoses, oil and filter helped to clean things up, inside and out.

An additional $250 was spent on new tires, tubes and rim bands. The 4.10x18 (replaces 3.50x18) sized tires were mounted on both wheels, which were over-sized for the rim width up front and were probably 40 years old. The bike got a good bath to degrease and clean the engine and chassis, while a fresh batch of Caswell tank sealer was ordered to help remedy the failing fuel tank cavity.
Removing the points cover revealed OEM Honda points and condensers in place. Once the engine has been evaluated for reliability, perhaps a Dyna ignition will be installed.  Compression readings ran right around 170 psi on all cylinders, which is right at OEM specifications.

The bike did come with some takeoff parts, including a poorly repainted stock fuel tank (with dent), a stock seat, one repainted side cover, the OEM rear outer fender (also painted yellow) and tail light assembly, plus the matching Tracy quarter fairing, which had not been installed on the bike. The fuel tank had an aftermarket keyed gas cap latch, which was missing the key portion. A screwdriver was used to open the latch and mercifully the fuel tank was shiny and clean inside. The OEM petcock was with the tank and a good usable part. The seat was original, but starting to split along the heat stamped seams, so would need a new cover, but can’t be used on this chassis due to lack of brackets.

I have to say that I failed to do my “due diligence” before the purchase in getting more detailed photos, asking more pertinent questions and working out the paperwork details. In hindsight, it wasn’t the best purchase I have ever made, despite being a hard to find CB400F with the one-of-three (reportedly) Tracy bodywork. The photos of the bike didn’t reveal the paint discoloration, leaking forks (which is an automatic with these bikes for some reason) and other details. Still, it had “good bones” but was probably over-priced for the condition that it was in.

Wrestling a 4.5 foot long hunk of fiberglass became taxing in a hurry. In order to seal the fuel tank, an order of Caswell epoxy sealer was made and received. They recommended using a quick splash of acetone or good old Dawn dishwasher detergent and lots of water to flush. The difficulty with the Dawn rinse was getting the tank dried out again afterwards. Plus there was quite a bit of the old thick sealer bits floating around inside which needed to be extracted mostly by shaking the whole assembly upside down. The whole thing is quite unwieldy to say the least, but after a few rounds of compressed air and a heat gun, it seemed to be ready to seal up with the Caswell product. 

The petcock had been removed and the holes sealed with a couple of 6mm screws and a rubber plug for the center hole. A plastic storage bag was employed to seal up a spare gas cap, when the tank was inverted to seal up the top surfaces. After mixing the sealant cans and pouring them down inside the tank, the cap was installed and the whole unit turned in all possible axis and angles in order to fully coat the rough interior of the tank chamber.  Surprisingly, once the gyrations were completed, virtually no excess sealer drained out of the tank openings. I’m not sure about the actual capacity of the fuel tank chamber, but it appears to be more extended than first realized. The bumpy internal surfaces seemed to have absorbed the fuel tank sealer, due to excessive surface area than would be found inside a steel fuel tank.

The tank cured in the SoCal sun for 2 days, hardening to a fuel-proof (I hope) glaze. Before remounting the Tracy bodywork, more repairs were made, including trying to piece together the original airbox and air filter assemblies, which were gutted because of the installation of the K&N pod filters. There are numerous pieces to replace in the air box assembly, which is mostly a carryover from the parent CB350F model.  A few of the pieces have been reproduced, but building up a system from scratch could run up into the $300 range. I slowly picked up bits and pieces from eBay sellers and my friends at 4:1 in SFO to resurrect the OEM air filter system trying to keep the cost down around $100, but I had to pay $50 just for the air box lid.

As an alternate to the Tracy bodywork option, a roundup of OEM headlight components was initiated to replace the massive H4 unit installed upon rather crudely-welded and modified headlight mount.  Again, an eBay seller came up with a whole front bracket and turn signal light assembly at a fraction of the “new price” or even some of the used parts on the market.
The inner rear fender liner was missing, so another check of eBay found a decent one for sale at a good price. The rear mounting holes are fitted with 6mm sized bolt holes which are a good bit smaller than the big holes drilled for the Tracy bodywork setup. A couple of fender washers will help take up the hole size in the rear frame crossover bracket and should clamp the whole assembly down securely.

The rest of the chassis was treated to new front fork seals and dust boots and the 13.25” Koni shocks replaced with a supplied set of vintage Mulholland branded shocks of the correct 12.5” lengths. Both wheels were stripped apart, cleaned and re-spoked with kits from Marty at the site. The front brake caliper was cleaned out with a new piston and seal ring installed. New pads completed the front brake repairs, but the master cylinder remains to be rebuilt.

The engine was first degreased then a spray-on, citrus based, paint stripper used on the leftover black paint splotches. For the most part, the 1-2 punch cleaned and removed much of the black paint, but there are still little nooks and crannies where the spray didn’t reach effectively.

Small stopper brackets were made to prevent the centerstand from hitting the drive chain in the retracted position. The usual stopper for the stand rests against the OEM muffler, which is no longer present.

New wiring leads were made for the sub-harness coming back from the rear bodywork section which feeds the tail light and turn signals. It isn’t clear as to whether the rear signal units are still available and of a kind which will mount up to the OEM Honda headlight mount and signal stalks.
After paying DMV handsomely for current registration and tags, the bike was ready for a short test run, finally! With a 16t front sprocket, the acceleration was brisk and the engine ran cleanly all the way up to redline in lower gears. The rear shocks/springs, which date back almost as old as the whole bike, seemed to have decent spring rate and damping, but these chassis are still 40+ years old and lack refinement to match even the cheapest of today’s street machines.

Surprisingly, the Kerker exhaust is relatively well muffled, but still gives off a distinctive sound when the revs come up to 5 figures. With a 458cc kit and a hotter camshaft, the whole package would be more in keeping with the futuristic body styling. The handlebars are stock OEM first generation low riser types, so the whole riding setup is café style, but not unbearable for us older folks.

To date, a week after the fuel tank sealing adventure, there is no sign of gasoline leaking from the tank. The petcock location is somewhat unfortunate, in that the petcock fuel fitting location puts the fuel line up next to the carburetor body. The whole bodywork package precludes use of the tool tray, which normally sits atop the air filter housing, so the practicality of this bodywork option is lacking in that regard.

Hopefully, the tainted paint work might rub out with compound and a good wax job. The whole bike is a bit above “rat bike” status, cosmetically, but it seems to be solid mechanically and is fun to ride, so far. It will either be the bike that I take to my grave or perhaps someone will feel the need to take over a restoration project like this and wind up with one very unique CB400F.

Bill “MrHonda” Silver

Thursday, May 23, 2019

A most unusual Honda CB400F… Part 1

My first Honda CB400F was purchased new, in 1975, when they first were made available at dealerships.  Apparently there were a few issues with the cylinder castings, as mine started leaking oil in the middle of the cylinder block, between the fins. So, it went back to the dealer for a new cylinder block and it seemed to be fine after that. I had been doing some roadracing with CB125s, but thought I would try the CB400F out in what was a new racing category, called “Box Stock.” You were only allowed to change the tires and rear shocks in this class and had to have working lights and full charging system components.

I discovered that these bikes were over-geared from the factory, so the first thing to do was to find a front drive sprocket that had one less tooth. This geared the bike down so it would pull redline in top gear more easily. I figured that much of the 350-400cc class competition, which consisted mostly of 2 stroke twins and triples would have had non-stock port jobs to boost their horsepower. Fortunately, Yoshimura Racing had been offering a nice bolt-in “road and track” camshaft, that helps build some power at the top end and give another 1,000 rpms to boot. You have to re-jet the carburetors and leave the valve clearances a bit looser, but otherwise the engine was pretty street-able overall. My competitors were somewhat surprised at my top 5 finishes in the first couple of races, but because I didn’t win, no one protested me. At one race, another stock CB400F showed up, but was woefully slow due to stock gearing and engine specs and they wondered why mine was so much faster…
My last race with the bike was at Ontario Motor Speedway, in Los Angeles. During the race, I tucked into the draft of a RD350, which was doing about 100mph on the straightaway. I pulled out of the draft with the engine hitting redline in 5th gear, I pulled out of the draft and then shifted into 6th at 100+mph. Top speed seemed to be about 105mph with that setup, so I pulled away from him and finished again in the top five results. I definitely got “stink eye“ when I returned to the pits though. As I coasted back to my spot, the Yamaha rider mumbled something like, “I’m not so sure that thing is stock.” The next week, I pulled the cam back out and sold the bike to my brother, who kept it for about 10 years, putting 40k miles on it without issue.

Since then, I have owned more than a dozen of these little jewels, including a 458cc-kitted bike that I crashed on, back at OMS in 1980 ending my racing hobby for good. I bought bikes from here and there, around San Diego and sold more than a few of them to exporters, who were shipping them back to Japan, where there was a great demand for the US models. The last two bikes I had came from Phoenix, AZ and one had been nicely restored. I sold it to a young guy who answered my Craigslist posting and said he was going to fly in and ride it back home…. to New York City! He made it back with no problems, giving the fresh motor a good hard break-in period.
These bikes do have their quirks and can’t really compete performance-wise with the likes of a KH400, RD400 twin or a Suzuki 380 triple. The engine was based upon the lackluster CB350F, which was slower than the CB350 twins of the days. To build the CB400F, Honda bored the 350 engine out to 408cc and then added a 6th gear to the transmission. Both engines shared the same carburetor rack and camshafts. The finishing touch for the CB400F was the iconic 4 into 1 exhaust system, which gave the bike such a sporting look. The downside of the exhaust system was that the header pipes were all of a different length, so the horsepower peaks were softened by uneven power pulses being reflected back from various length tubes.  These engines really perk up with a nicely-designed header system with equal length pipes. The Kaz Yoshima pipe added 1,000 rpms and a couple of horsepower when installed in a stock or modified machine.

The camchain tensioner system can be a source for problems. The tensioner shaft and spring push against a rocking arm that wraps around the crankshaft and pushes up on the bottom of a long tensioner blade which bows in the middle to take up the camchain slack. When the camchains are not kept regularly tensioned, the chain whips off of the lower sprocket far enough to rub against the pivot point of the camchain tensioner arm, eventually smearing metal across the hinged portion. This effectively disables the tensioner from normal operation.  Fortunately, Honda installed the tensioner rod down a hole in the front of the engine case, sealed by a short, threaded bolt and washer. Removing the cover bolt allows access to the end of the tensioner rod, which can be pushed downwards by use of a longer bolt with the bottom threads removed. You must use caution as it is possible to over-tighten the tensioner rod, causing the tensioner blade to be improperly tensioned against the chain. When this occurs, the camchain will “sing” due to excess friction of the chain and tensioner blade.  If left in this condition, the tensioner blade is prone to break into two pieces.

The other critical maintenance problem is the actual camchain tensioner bolt. Normally, you loosen the bolt, which allows the spring-loaded tensioner rod to push up gently against the tensioner blade, taking up the slack in the camchain. The bolt is only 6mm and has a machined “waist” in the middle to allow for installation of an o-ring to seal the bolt against the engine case threads. It doesn’t take very much force to snap the bolt off at the o-ring slot and then you have BIG PROBLEMS! I have tried to remove the broken bolt off with an EZ out, but they often break off inside the broken bolt piece, making the problem MUCH WORSE. I have also drilled out the broken bolts and drilled/tapped the hole for an 8mm bolt and a matching alloy crush washer to seal up the threads. The worst one I encountered wound up with me splitting the bottom engine cases and having a machine shop use an EDM machine to burn out the old bolt, allowing installation of a new stock bolt once again. Honda seems to have changed the design to a 286 (CB250-305 twin) part which doesn’t have the o-ring groove now, which should lessen the broken bolt issues of the past.

So, these are some critical issues that needs to be checked when you are looking to purchase a 350-400F Honda four.  Because of today’s diluted gasoline, I have found that vintage Hondas often require some bigger main jets to help offset the alcohol in the gasoline. The cross-country CB400F had #80 main jets in place of the stock #75 mains, even with a stock air box and muffler system. That bike ran smoothly and with good power at sustained speeds of 80+ mph for hours on end. Changing the intake or exhaust system nearly always requires carburetor calibrations different than stock settings.

The latest find….
Despite having my right ankle bound up in a cast/boot for 4 months after ankle fusion surgery, I continue to keep my eyes open for something interesting, like a CB400F. The prices of pure-stock CB400Fs have jumped in recent years, as supplies run low and parts become extinct. My non-related friend David Silver has had numerous CB400F parts remanufactured to fulfill all of his restoration bikes, which have become a staple in his business model.

A daily email, from the “Bike-urious” website, lead with a “1975 Honda CB450” with a “one of three” Tracy body kits and custom paint job. The bike listed only had 6,000 miles showing on the correct 1975-only 130 mph odometer. The bodywork was sleek and gave the bike a whole new character. The stock exhaust had been ditched for a Kerker system and the tiny stock headlight had been swapped out for an 8” searchlight beam. The engine was painted black to match the bodywork, perhaps, but nothing was known about whether the engine had been modified or not. The seller had gotten it from an ex-Tracy employee, who had stored it since the 1980s. The current owner, named Brian, resides in a quaint town in No. Cal., with a population of about 500. He is a 30-something guy who claimed to love restoring vintage cars and bikes from time to time. I was able to reach him and have a long talk about the bike and my history with the CB400F models, so we struck a deal and I made arrangements to have it hauled to Spring Valley from 750 miles away.

The bike was missing the center console indicator light panel cover and the centerstand. Fortunately, the warning light panels have been reproduced, as they fit 400-500-550 and 750 models. “Z-1 parts,” up in Oceanside, CA set me up with a killer deal on one, but they can be found at and several other sites and cost about $60. A quick check on eBay turned up a decent centerstand and pivot bolt for $35. The spring and spring hook wound up coming from the UK, where the hooks were custom cut from stainless steel.

Brian had sent a video of the bike running up and down the road, so I knew it ran and didn’t seem to smoke or have running issues. The bike has K&N pod filters in addition to the period original Kerker 4into1 exhaust pipe, so one hoped that the carburetors had some adjustments made when the bike was built.

Thursday, May 9, 2019

How to find stuff…. Vintage Honda parts and others

Like many of my peers (Baby Boomer-era motorcyclists) who happen to have the vintage Honda acquisition affliction, the key to completing projects is finding sources of vintage parts. I am subscribed to numerous forums on Facebook and with the VJMC group, which are full of banter back and forth on where to find parts, how to make repairs and whether to restore or go “resto-mod” with their latest barn finds.

Thirty years ago, the communications options were few: US mail and a few clubs like the VJMC newsletters, plus magazine and weekly publications. Hopefully, an ad for a wanted part would include a phone number which was probably going to tap into your “long distance” portion of your phone bill. With no phone number offered, you would have to write a letter to the seller and hope it arrived quickly, before other suitors barged in and snapped your wanted item up, leaving you with the “It just sold” PTSD syndrome.

In recent years, with the advent of the Internet and so MANY sales options for bikes and parts, speed is still a key factor, but finding the part in the first place can be the most daunting part of the process. For a simple look around, any of the internet search engines like Google, Yahoo, Firefox, Internet  Explorer, etc. will often bring a few parts sources into focus. It is VERY helpful to use several search words in your quest for the right part. Just putting in “Honda CB77” will garner you about 1 or 2 million page results. Using “Honda CB77 ignition switch” narrows it down drastically.  If you want really specific results, then use the OEM part number in the search window. In the case where CMSNL.COM site comes up with SWITCH,COMB, product number: 35100-268-030  supersession: 35100-273-000, it appears that two options are available. However if you are aware that the 273 switch snout is an extra inch longer than the correct 268 code part, you might want to think twice about the purchase. 

Modern internet sites which host OEM microfiche-type illustrations and drawings of the parts, along with part numbers often only show the last generation part numbers and don’t include a full history of how the part got from 268-000 to 268-030 through the years. Look for other websites which highlight US Honda models, which often use American Honda Motor Corporation microfiche feeds from the manufacturer.  In some cases, you might have to access a Japanese website, which might have a more concise parts book listing containing the older part numbers. An important part of the whole hobby is the excitement of the “search and find” cycles, which are a small part of the whole restoration process.

To ascertain the most correct part number for your machine, it is best to have a period copy of the OEM parts books that does show the part number succession history.  I have a copy of Honda’s 1980 parts history book, which is often a handy resource to find part numbers which have slipped into oblivion through the passage of time. Many years ago I was able to obtain a rough photocopy of a 400 page NPS conversion booklet, which listed just about all of Honda’s old part numbers (pre-NPS in 1965) and includes many of the superseded part numbers and/or ones which were utilized, but perhaps never assigned to production machines. The list started with the 001 code C100 and ran up into the 1965 CB450K0 era, including some of the Police bike part numbers.

I do receive more than a few requests for parts or part numbers for any size or pre-1980 (1960s mostly) vintage Honda and sometimes the results are just a few keystrokes away. It’s easy to assume, sometimes, that people are either lazy or perhaps don’t have the resources to access a lot of the vintage parts resources. You never know a person’s ability to use technology or their own thought processes during a parts search, even when a request seems extremely simple to perform. On top of that, you can’t assume that the request comes from someone who is well-versed in the particular model’s history. I have stored up over 50 years of experience working with Honda motorcycle products of all sizes and vintages, so it seems perfectly simple to track down a part or part number, if it is remotely available in an online search. 

In the past 10 years, many of the “old reliable” vintage parts sources have all dried up and owners retired. Currently, the remaining sources for vintage Honda parts are:,,, and . If course can often offer up various parts sources that are regular online businesses or the one-off odd part that someone found at a swap meet or have dug it out of the back of their garage. The most successful parts finders take advantage of all available resources, including extensive networking with owner’s groups, Facebook forums, Yahoo groups and vintage motorcycle clubs like the .

For internet-savvy people, valuable resources are available, through the previously mentioned various forums, which can cover vintage motorcycles in general or a specific model/series like Honda pushrod Cub 50 (vs. the OHC version). Internet forums can join people from across the globe that care about a specific make/model and might have that rare part that is being sought to complete a project.  Often, some very esoteric parts or whole bikes can turn up when you connect with the international community of like-minded enthusiasts.  Novices can sometimes get scolded for not specifying a year/model and part number for the wanted item, but that is part of the learning cycle. No one woke up one morning with the full history of a specific make/model in their brain, much less the ability to repair or restore that machine. 

In writing stories like this, I hope to enlighten and encourage even the most novice owners to jump in, speak up, ask for help and listen thoughtfully to advice from the learned ones who do specialize in that same machine type. In my 50+ years of Honda experience, I have found that you do usually “Meet the nicest people on a Honda” and the vast majority of owners and parts sources are helpful, friendly and ready to do their part to help you finalize that vision of the fully-functional and/or fully restored vintage Honda motorcycle.

And if you really get stuck trying to find a source of parts or just an accurate part number, ask MrHonda! I’m here to help…

Bill “MrHonda” Silver

Age before beauty, when vintage bike shopping…

It’s hard to resist that perfect dream bike, when it suddenly comes up for sale, especially when it is described as one-owner, like-new, all stock and original, etc. When properly stored, you can often bring those sleeping beauties back to life with just a new battery, fresh fuel and spark plugs. Most of the time, however, the actual story is that they were left with old fuel, old oil and uncovered in the back of some garage, shed or storage building by an owner whose life was overtaken by events.

Recently, an unmolested, 600 original-mile 1988 Honda Hawk GT650 popped up on Craigslist, by the first owner who bought it as a Christmas present to himself. He rode it 600 miles and then parked it deep into the back of his garage. The last license tags were from 1994 and apart from a change in the hand grips, the bike was absolutely original and stock.  It was buried so far deep in the garage that apparently light and ozone aging wasn’t a big issue both of which can cause significant deterioration of the cosmetics and any exposed rubber components.  When the bike was pushed back out to the front of the garage for sale it gleamed like it was just a few years old, not thirty years old.

It was one of those bikes that you just can’t let pass by, but there were dark secrets, yet to be discovered, after a successful purchase and delivery back home at Casa de Honda. In this case, the bike sat for years with perhaps less than a half tank of gasoline remaining. The years of heat and cold cycles inside the garage caused the airspace inside the fuel tank to condense moisture out of the air resulting in rust and varnish build-up inside the tank. At some point in time, a misguided attempt to revive the bike occurred and a can of Kreem fuel tank sealer was poured into the fuel tank, right over the rust and varnish. The congealed mess was the first thing noticed when the fuel tank cap was opened up for the first time in 25 years. Eventually the tank was rescued after a combination of degreaser, phosphoric acid, Metal Rescue and MEK were used to dissolve the rust, melt away the varnish and loosen the Kreem coating, which was locked into the many nooks and crannies inside a CA spec fuel tank. Eventually, it was clean enough to use once a $60 kit of Caswell fuel tank sealer was installed into the newly cleaned tank internals.

Of course, the rest of the fuel system required cleansing and a few new parts. It is easy to overlook some crucial components and systems when you are star-struck by the overall appearance of a lightly-used machine that is 30+ years old. There are many small details, easily overlooked or disregarded, that can trip up the maiden voyage of a newly revived classic bike.

How about a Honda Four?
Honda’s four-cylinder street bikes have been on the scene since 1969 and come in an array of shapes and sizes through the ensuing years. Rehabbing these machines takes extra care and effort in order to regain their former glory, especially from a mechanical aspect. Honda built thousands of 350, 400, 500, 550, 650 and 750 OHC powered machines for a ten year run and plenty are left to discover and revive in the 21st century. A recent “internet find” in the form of a 1975 CB400F, which was showing 6100 original miles, is a good case in point.

This particular bike was offered as a “runner” with original miles.  It had been stored for some 40 years by the original owner, then quickly revived and ridden sparingly in the past year by the current owner. There is a whole blog page about this particular machine, which had been clothed with rare (1 of 3, according to the story) Tracy one-piece bodywork. The bike was purchased without the benefit of an actual live inspection and detailed photos, which might have given a better indication of the actual condition of the bike. All indications are that the miles are probably genuine, however numerous modifications involving the bodywork installation and other “mods” left the little machine suffering in many areas of its various systems functions.

For some reason, virtually every used Honda CB400F that has come my way has needed fork seals, tires, brake caliper/master cylinder overhauls and carburetor overhauls, whether it was running or not. This bike was not an exception to the rule…

First, the battery wasn’t sufficiently charged enough to start the engine, when the bike was delivered from 750 miles away. There was little fuel left in the tank because the bottom of the fiberglass was leaking gasoline right through the original fuel liner and bodywork layers. An overnight charge of the battery brought it back up to function allowing the engine to spin over heartily. The carburetors were removed for cleaning and inspection. Running off of an auxiliary fuel tank, the engine fired up on the freshened up carburetors, which were mounted on new intake manifolds. The bike sounded somewhat rough at idle and seemed a bit erratic in low speed running conditions. New spark plugs were installed and spark plug caps checked for resistance values. Three of the four caps were up at around 9-10k ohms and the last was about 6k. Standard resistor caps are 5k ohms, so there was definitely excess secondary resistance in the coil outputs. The coil wire ends were trimmed back slightly to uncover fresh wire strands when the caps were installed. The spark timing was checked and adjusted to prevent over-advancing spark timing. Aging spark plug caps have become a major issue in reviving these vintage fours in of all sizes offered from the 1970s.

When the carburetors were disassembled and cleaned, new o-rings were installed on the fuel delivery tubes, which are interconnected between the bodies. Disconnecting the carb bodies in order to change the o-rings requires attention to the interconnecting linkages and how they come apart and go back together again. There is a lot of extra effort involved in cleaning and resealing the connection tubes, but it is a vital step in a successful carburetor cleaning phase. It is easy to assume that the tube o-rings are still okay, but when old fuel is left in the carburetors, the leftover fuel residues will easily be flushed into the float valves, causing flooding issues later on. Going to the work in removing and cleaning the carburetors is something that you don’t want to repeat again, especially with certain models.

When the 400F was fired back up, the #4 cylinder pipe was cold, even after a few minutes of run time. Sure enough, a bit of debris had worked its way into the #4 carburetor idle jet and blocked the passage of fuel fed to the idle circuit. Carburetors on the 350-400F are relatively easy to R&R, so it doesn’t take a long time to pull the rack and recheck the jets and float levels, but the carburetors on the CB500-550s are quite challenging to remove with the close-fitting air box in the way. So, take your time and be as clean as you possibly can be with carburetor work. Fortunately, the engine went back on-song again, once the pilot jet was cleaned and the engine really began to sound like the low-miles unit that was indicated on the speedometer.

Long-term storage usually causes issues with the ignition points, as well. Generally, one set of points is usually open on a four cylinder machine and corrosion can form on the open point faces, causing high resistance when trying to trigger the ignition coil primary windings. The problem with points is that the rubbing blocks wear down, causing a decrease in the point gap. This leads to late spark timing and sluggish running problems. Point face corrosion can prevent the transfer of power through the points in extreme cases, so that the coils never fire at all. A small point file or some emery cloth will burnish the contact faces to allow a nice clean metal-to-metal contact which is what the ignition coils really appreciate. The points are basically just an adjustable “on-off” switch for the ignition coils. The point gap needs to be around .012-.016” wide, then move the base plate until they just open at the F mark alignment on the crankshaft flywheel or spark advancer markings.  Another feature to check is the spar advancer unit for full function. The point cam can get gummy or even seize up, preventing spark advance or causing a slow idle-down condition. Most of the 1960-70s machines, which were equipped with points and condensers, can be retrofitted with efficient and trouble-free electronic ignition systems, which require nearly zero maintenance.

It’s a magical moment when you discover that wonderful rare bike find, still in near-new and original condition, but take a moment to consider the amount of time, money and work that will probably required in order to make the inner beauty match the outer beauty. If you have the ability to do the bulk of the work yourself, the end result will be gratifying and you will save a lot of money in repair work. If you are not so mechanically adept, be prepared to pay for technical services to be rendered, often in ways that are not apparent on the surface.  Hopefully, you have done your studies on a particular model and have prepared yourself with tech data and resources for parts and services.

Motorcycles are complex machines with numerous interconnecting systems, all of which must be working at normal specifications in order to have a safe and enjoyable riding experience, well into the future. Don’t let the beauty overwhelm your common sense about what lies ahead in the forms of repairs, restoration and general maintenance of your dream machine. The little CB400F reminded me about this lesson, especially when buying over the internet.

Bill “MrHonda” Silver