Auto Clutch Question

I have restored my first CT70 K0 and overall I would give myself a "B" grade on it, I haven't driven one of these since I was a boy. I did rebuild the engine and it starts up on the first kick every time, but the problem is the simi-auto clutch is not slipping when the bike is stopped so the motor dies when I come to a stop every time. I used a Shell Rotella SAE-30 conventional oil. the clutch is supposed to slip when the bike comes to a stop correct? or are you suppose to upshift to neutral when coming to a stop. if its supposed to slip when coming to a stop then maybe I made an error with the clutch pack when I rebuilt it? when I tested when I rebuilt the engine it the clutch pack would spin one direction but not the other way. Any advice would be greatly appreciated, thank you

Did you go thru the clutch adjustment process??
That may be your problem.

Thank you Kirrbby, yes, I have tried this, the only thing that I have noticed when adjusting the clutch seems to be the easiness or hardness of the shifter going into or out of another gear.

Some of the aftermarket clutch discs have some burrs on the teeth...around the inside diameter of the discs. The burrs cause the discs to...NOT be able to slide, side to side, or, in and out. I usually file all of those teeth, or clean them up with a small grinding wheel.

Did you use discs from tbparts maybe? Or did you use Honda parts?

Did you make sure to mesh the clutch gear into the small primary gear when you installed the clutch?

In addition probably not your problem yet but you need to use an oil for wet clutches and has the shear strength for gears not an automotive oil,something like a Honda GN4 or Valvoline motorcycle oil. That type of automotive oil will cause the plates to stick together. The clutch does not slip when coming to a stop but does disengage,hard for me to explain but its a combination centrifugal/manual clutch. The centrifugal part lets you stop in gear,the "manual" part lets you shift between gears by activation with the gear shift pedal. Nice job on the restoration

I'd give your restoration work a higher mark than you did. You just need to sort the clutch...and ditch the shower cap the seat is wearing.

Every bike takes at least a little time & tweaking after assembly. Sounds to me like the clutch may be incorrectly assembled, or incorrectly installed on the crank. There's an easy bench test for a semi-auto clutch...you should be able to spin the clutch pack by (with resistance) in one direction only. If you can't, time to figure out what went pear-shaped during assembly. The most common issue is a misaligned bottom plate. Next most common mistake is misalignment of the primary drive gear with the clutch center drive element.

Since this is assembled and running nicely, and you say that preload adjustment(s) change shift quality, I'd start be testing the manual phase of clutch operation. If preload is anywhere near correct, then pressing & holding the shifter, in either direction, should allow the engine to freewheel, regardless of gear. If there's no clutch slip, at all, I'd suspect primary drive gear misalignment, that's very easy to do. If you get some release action, then it's probably a clutch assembly mistake...easy to do and easy to correct.

Slider303 said:

I have restored my first CT70 K0 and overall I would give myself a "B" grade on it, I haven't driven one of these since I was a boy. I did rebuild the engine and it starts up on the first kick every time, but the problem is the simi-auto clutch is not slipping when the bike is stopped so the motor dies when I come to a stop every time. I used a Shell Rotella SAE-30 conventional oil. the clutch is supposed to slip when the bike comes to a stop correct? or are you suppose to upshift to neutral when coming to a stop. if its supposed to slip when coming to a stop then maybe I made an error with the clutch pack when I rebuilt it? when I tested when I rebuilt the engine it the clutch pack would spin one direction but not the other way. Any advice would be greatly appreciated, thank you

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Slider303...That is a beautiful bike! Nice job.

You guys are awesome thank you for all for the feedback, Kirrbby, I did buy aftermarket clutch disks from CHP I would have purchased Honda ones but they were out of stock so I purchased the other brand. I thought after some riding around maybe it would break in but I have about 15 miles on it now and its made no difference when I come to a stop it will kill the engine. I read somewhere on the forums that using conventional Shell Rotella oil was ok to use, I will order some Honda GN4 oil.

I think I'm leaning to what racerx is saying, and I screwed something up putting together the clutch pack together, it was my first clutch pack rebuild so making a mistake putting it back together is highly likely. Maybe I will order a clutch pack thats already assembled to take out any error that I might cause. I will keep you all posted when I get the new pack of the results.

Again thank you all for the complaints on the bike, and your suggestions to help, Thank you

Slider303 said:

Again thank you all for the complaints on the bike, and your suggestions to help, Thank you

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The only complaints I have is that my bike doesn’t look like yours.

airblazer said:

The only complaint I have is that my bike doesn’t look like yours.

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Geez, sorry guys I meant to say thanks for all the compliments on the bike! sorry and thank you!

Problem fixed! you were right RacerX! It looks like I F'ed up the clutch when I "tried" to rebuild it. I replaced the clutch pack with a new one that was already pre-built...... and Wow so that's what it's like to have a working clutch! everything now seems works better, all the shifting between the gears, able to come to a complete stop now, this is great! Thank you ALL for your advice and help!