QuestionHello,
Last year I purchased my first motorcycle, a 1972 Honda CB500, which had been sitting for the past decade in the sellers garage untouched. Last summer I stripped it down to the motor on frame, and rebuilt it back up, replacing seals, wiring, forks, tires, oil/filter, air filter, lights, throttle/clutch cables, rebuilt carbs, seat, basically anything that will rot. I should mention I had never even changed my cars oil before this, 100% inexperienced. This spring, I began riding it (my first experience on a motorcycle) and soon noticed the clutch would stick and slip soon after I changed into a gear and would increase my rpms. It was also noted that when changing gears, sometimes it would be hard to pass from one gear to another. To specify, squeezing the clutch lever felt normal, and the clutch engagement feels normal as well, but when attempting to change gear, the peddle wouldn't move at all. Usually when this happens I end up shifting into the opposite direction gear, and would hear a clunk when the gear actually changes. Sometimes I would be able to initially change into the next gear when this occurs, but would then get the clunking noise felt in the peddle. Hoping this was related to worn clutch plates, last week I replaced the friction plates with new ones. On a test ride, the clutch engages and releases very smoothly now, but I am still having the issue of the gears getting stuck or hard to progress through. I have checked and cleaned the clutch lifter, lifter sleeve, and lifter rod. They all appear normal, without damage, but were caked in dirt and grease. All were replaced with ample greasing. This did seem to help, but the issue is still there. Any ideas? I have thought of looking at the gear drum, but this may be way out of my league. Thank you so very much for any assistance you may provide. I have read many other blogs on the issue, but have yet to find any compelling evidence as to what is my issue.
AnswerHello Justin,
There was some problems with some of the CB500
transmissions so Honda redesigned it and starting
selling the CB550 with a much improved design.
When having shifting problems the clutch
is always the first suspect and
then you start by examining all the
shift components that lie outside of the main engine cases.
This starts with making sure the shift lever
is not bent, slipping or hitting on anything.
Next is the shift shaft that the lever attaches
to. The shaft can get dirty or bent and
it will prevent it from working smoothly.
The shift return spring in the clutch case has to be able
to rachet the shaft back and forth easily when shifting.
Next is the shift return spring, and the selector mechanism that
pulls the shift drum into position for each gear.
There are a alot of parts for me to describe
so I will just say that all the shifter parts
need to be examined for wear or problems.
There is a plate on the end of the shift drum
with some pins in it. These plates are held
on with one screw and can come loose.
There is a shift drum locator plate that
keeps the drum from moving in and out too much.
They can be shimmed to tighten the drum up.
You can remove all these parts and try turning the
drum by hand to see if it is hanging up
inside the transmission.
You will have to block the back wheel
up and turn it slowly by hand as you try
turning the shift drum through the gears.
If the shift drum slots have worn and the
shifting forks are catching on the drum
slots then you would have to split the bottom
of the engine to repair the transmission.
Always check for parts availability first.
The bottom line is if carefully tuning
the outer shifter assembly doesn't help
then the engine has to be split
to check the transmission drum and forks
and gear teeth.
The CB550 has a better shift unit and that engine will
fit in your frame but that is another story.
Good luck!
Wayne S.
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