Doing favors for friends can sometimes have very unfavorable outcomes, at least when it comes to repairing vintage motorcycles, sometimes. My slightly fanatic friend, Lea, made friends with a guy who had purchased a 1968 CB450K1 from someone in LA who had done some attempt at making a “café racer” out of it. After going to a lot of work to cover the entire wiring harness and all the cables and anything external with wire wrap and zip-ties, the seller failed to disclose the fact that the motor had a failing kickstarter mechanism and compression readings that were 50 psi low from specs.
The bike was dropped off with a dead battery and unknown history. Speedo was showing only about 8k miles and the front tire was original, so it could have been correct. I put the battery on the charger for several days and it came up with ZERO volts, so a fresh battery was the next item on the parts list.
The bike had been in a local shop for several months. They determined that the bike had a bad ignition coil and apparently were trying to find a NOS OEM coil for that side, which was a tough thing to find, these days. I went on EBay and found a good looking used coil set for $30 delivered, in advance of the bike coming to me, so hoped that this would be the only issue to deal with, in getting the bike back to a normal function again.
When the bike was dropped off, a whole trash can full of parts, plus a couple more cardboard boxes came with it. First discovery was a spare set of coils! Most of the parts removed from the stock bike were in the boxes of spares, including mufflers, seat, front fender, battery boxes, air filters, etc.
An incorrect starter solenoid was hanging off the side of the frame and wouldn’t bolt back to the battery box due to insufficient starter motor cable length. I rummaged through the spares and found another solenoid and a matching battery box combo that looked like it should work properly. After cutting through numerous zip-ties and peeling off the sheathing, I was able to swap out the battery boxes and install the solenoid, but the cable was still too short. The cable had been incorrectly routed to the starter motor in front of the motor instead of behind it, so I had to pull the left side cover (after removal of the left exhaust pipe and footpeg), to access the cable mount and evaluate the routing situation.
I had to disconnect the cable end at the starter motor and fish it back through the space between the motor and engine cases, then feed the extra length down beneath the motor, around the countershaft sprocket area and then stretch it up to meet the solenoid post, which barely made it to the post.
In the meantime, while the battery was being charged up, I pulled the carbs and checked them for cleanliness and float level adjustment. When I pulled the bowls, the float needles fell out on the bench. They are supposed to stay positioned within the float valve seat, but the little tangs on the outside edge of the float arm were bent away and not staying high enough to retain the float needle in position. I pulled all the jets out, checked them for size and corrosion, reworked the float arms and set the float levels before buttoning them up.
The bike “set-up” was pod filters on the carbs and some kind of foot long muffler extensions with some kind of baffle installed. This kind of modification generally leads to the need for carb re-jetting to compensate for the changes in the intake and exhaust tract lengths. I would worry about that after I got it running, I thought. After the battery was well-charged, I installed it into the battery box and switched on the key to check electrical functions. The primary ones I was concerned about was the electric starter and the ignition coils. The starter button worked fine and the motor began to spin over right away. I checked for spark and saw little glimmers of electron flow jumping across the plug’s gap. It looked promising at the moment. I pulled the dyno and points covers, checked for correct orientation of the valve adjustment shafts and adjusted the point gaps and timing to specifications.
With the electric starter spinning easily, I finally decided to check the compression with my gauges. Checking both sides twice, I could only see 120 psi come up on the instrument face. Standard compression is about 175psi generally, so there were some real issues happening inside. About the same time, I discovered the kickstarter arm flopping back and forth with no spring return. That is usually an internal (as in split the cases) repair job.
There was a little fuel left in the gas tank, so I mounted it back on and connected the fuel lines to see how it would run. Coughing and spitting out blue smoke, the motor roared to life with the two little stub pipes crackling loudly. I let it warm up for a few moments, trying not to completely overwhelm the neighborhood with noise, and then shut it down. I decided that this was enough for now and made a report to the owner, with recommendations to just sell it as-is, barely running. Then, in discussions with my friend Ron, he mentioned having a spare CB450 motor sitting in his garage for the past 20 years; condition unknown.
I updated my report to the owner and told him about the spare engine that MIGHT be a viable replacement for his dying unit. He agreed to give it a try and I picked up the motor after a 40 mile round trip. I had pulled the spark plugs and cam covers off the spare motor and it looked very clean and unworn from what I could see. I loaded up the 130 lb lump and drug it home for a transplant. The spare motor had been stripped of the starter motor and stator/cover, so after draining the oil from the original bike, I removed the whole assembly from the bike and laid it next to the spare, in order to swap parts back and forth. When I pulled the rotor on both engines, the starter clutch springs were obviously worn and shortened, so I went to my part supplies to renew the clutch assembly with fresh springs. I was able to swap the parts over to the new unit and buttoned up the covers.
Somehow, I was able to hoist the replacement motor into the frame and install all the bolts and brackets for the install. After hooking up the ignition and carbs, I slid the tank over the frame again, fed the carbs and hit the starter button with no exhaust system connected to the engine, just to hear it run. I had primed the motor with high-grade oil and put assembly grease on the cam lobes to help keep them safe during the start-up. It lit off fairly quickly and I was drowned with the staccato bark from the exhaust ports. I listened for a few moments, and then shut it down to go have some lunch.
Coming back to the project just 30 minutes later, I discovered a small pool of oil beneath the engine. The clutch pushrod seal had pushed itself completely out of the cases while running. I fished around the shop and found a spare seal that I had ordered when I did the last CB350 repair job, in December. I got that installed, and then added the header pipes (which were heat wrapped) and the stock OEM mufflers to the chassis. With a more silenced exhaust sound, I was able to listen to the motor more carefully and noticed a heartbreaking rhythmic knocking sound coming from somewhere inside the engine. I really hadn’t heard anything like that before and knew that it wasn’t a connecting rod sound because of the cadence. I stripped off the fuel tank and the right side exhaust and footpeg (which ended up happening way too many times during this repair attempt) and then pulled the clutch cover and oil filter for inspection. It sounded like it might have been coming from that part of the motor, but after complete disassembly I could not see anything amiss in that area, so reassembled it and started it up again. Same noises, but now they seemed to be coming from the top end, perhaps from cam chain guides/rollers. These engines have numerous guide wheels and the tensioner on the back of the cylinder block. Originally, they are black rubber, but with time and heat cycling, plus hot oil exposures, the soft rubber turns into a hard plastic that starts chipping in extreme cases. All I could figure was that something had happened to the roller system inside and I was not about to go in there to see what it was. I have never had an affinity for the 450s, perhaps because I was almost killed on one that I was trying to work the bugs out of, back in 1972.
So two dying motors and no happy ending in sight, baring a major engine rebuild that was way outside the finances of the owner, I made my report and called it quits. The owner agreed and I delivered the bike and all the parts, including the original motor back to his house with suggestions for the future to contact me first before buying anything like this again. I was relieved to be done with this demon machine and didn’t want anything more to do with CB450s, ever again.
Of course, the universe has a funny sense of humor and proceeded to serve up another CB450 experience, again at the hands of my otherwise wonderful friend, Lea. She had sent me photos of her in the saddle of a later model CB450 some months before, all blacked out and looking tough. She coaxed me to taking a 50 mile drive up in my truck to fetch this bike from her friend Richard, who is primarily a Harley guy, but gotten this Honda for free and decided to see if he could paste it back together again and have a “spare bike” to ride, on occasion.
Lea was all excited for me to ride the bike and give her my opinion of this machine which she was going to adopt, at least temporarily, to add to her patio, next to her low-miles CB350, which I had just finished wrenching on for another 3 hours, a few days prior. At first the bike wouldn’t start, even though it had been running an hour earlier. After pulling plugs, checking fuel bowls, I determined that the KILL switch was in the OFF position, which wasn’t apparent because the knob would spin 360 degrees with no real ON-OFF detent function. Once that was determined the bike started up immediately. There were a few noises, but nothing like the previous bike’s experiences.
The bike’s starter button was bypassed and another button installed down below the seat, towards the rear. The tail light was replaced with a small two element custom LED light, as were the turn signals in the front. These didn’t work because the original flasher won’t trigger LEDS due to lack of current load.
I could see a lot of hacked wiring and automotive connectors splicing wires together here and there, so it all looked very unimpressive to me. We decided to take the bikes and go to lunch at the café near the lake. I rode the 450 and Lea went on the back of the H-D with Richard. I didn’t get too far before feeling like the engine was running out of fuel. I flipped the petcock to RESERVE and waited for some response, which came grudgingly. Then the engine seemed to go off on one cylinder, catch on and start to die off altogether. I pulled off to the side of the narrow road, checked the fuel and listened to the engine again, which seemed to catch back on to both cylinders. As I began to move forward I could feel the front wheel digging into the dirt, more than usual. Earlier, I had mentioned that these old bikes tended to have the caliper pistons stick when they sit for a long time and that seemed to be happening now. I nursed the bike down the road another half mile and barely made it to the parking lot of the café.
I wasn’t looking forward to the return trip after lunch, but felt I could probably get it back to Richard’s house without mishaps. My adrenals were on high readiness as I again felt the engine go off-song, stalling as if it as losing all fuel to the carbs. I pulled over again and it caught back to life. I was not using the front brake at all, so the whole journey back was very unnerving and I was glad to have made it back on one piece. These are the kinds of incidents that can put you down and in the hospital due to misbehaving motorcycle systems. I was not amused or happy to have had that experience that day.
Lea, of course, just saw it as an opportunity to learn more about fixing Honda bikes, so we loaded it up in the truck and dropped it off at her house, where she immediately posted photos of it on Facebook. I am going to be more in “remote mechanic” mode on this one, letting her discover what it takes to get things fixed on her own, with email support for now. I know that I will probably get my hands back on it again, for some part of the process, but I am more than happy to confine my activities to the bikes I know best: 250-305cc Honda twins.
The take-away message here is that a. Beware of “modified” vintage bikes, unless you know them well and can evaluate/trust the builder’s skills. b. These bikes are continuing to deteriorate and parts are becoming increasingly scarce and expense.
Bill Silver (on 450 burnout for now).
P.S. I went back to Lea’s house last weekend, where we removed somewhat loose coil set for cleaning of the ground paths and secured them to the frame, found a bad spark plug cap, reset the worn out points so ignition timing was correct and got it going again. Still hesitating some, but ran much better than before. I rebuilt the brake master cylinder and caliper, so it has reliable brakes now and can be driven around safely, as we address remaining issues by replacing the wiring harness, amongh other concerns. More to do, but I have a CB350 engine waiting for parts and reassembly, plus an upcoming 1961 (again!) CB72 250cc Hawk restoration to do.