Topic: Considering a CT90. How does the clutch work?

[fmctm1sw]

Got offered an old CT90 for $75.  If I recall it had clutch issues and maybe compression issues too.  One thing I am curious about is how the automatic clutch works in those.  I saw a photo of somone with one of them apart and I expected to see a lot of trickery and complicatedness in there.  All I really saw was clutch plates though.  It can't be that easy, does anyone have a good link to a explanation of how that works?

[Old Scrambler]

Go to the VJMC site or any HONDA dealer.  It is a centrifugal clutch. When the motor is at idle, no pressure on the clutch so it slips. At higher RPMs the throw-weight puts pressure on the plates to lock them up.  When you shift gears it is best to relax the throttle for an instant while you work the shifter. All up....then all down to neutral.  Low compression is common on small singles that have been sitting or are worn.  New rings and a valve grind will get you going. If you have a very badly worn cylinder, you can purchase the 110 kit that was a stock production in later years.   

[bucky katt]

ah, so like a go-kart then?

[MCRider]

ah, so like a go-kart then?

Not exactly. On a go kart (at least the one I had) the throw weights double as the friction. On the CT90 (whch I had one with a Powroll 110cc kit) the clutch friction part looks like a conventional clutch. IIRC  The throw weights don;t double as part of the friction drive mechanism.

Also, on the CT90 part of the throw of the shifter does duty as a "clutch lifter" like pulling in the lever/ cable. Again, IIRC.

The CT90 is not so much an automatic as it is a clutch lever-less transmission. YOu still have to push a shift pedal and things are still happening like a conventional system, with a minimum of exceptions.

An example, if you depressed the shift pedal all the way, you could rev it to the redline. Then allow the shift pedal to return to its relaxed position. THis would engage the clutch a pop a wheelie.