Clutch Curiosity

[go_hercules]

I was just wondering if any other builders besides Hodaka ever mounted the clutch to the crankshaft. I searched on this quite a bit but couldn't find even one other. Just curious to know.

[Hydraulic Jack]

Maybe Fuji or one of the predecessors of Hodaka. Or a scooter of some sort. Otherwise, I have seen them on mini-bikes and early go-karts as external centrifugal clutches on the crank. Not the best location if rotational mass is an issue.

I think Lee Fabry managed to remove the Hodaka clutch and mount a KX-80 clutch on the main shaft of his 97, but it was all custom stuff. It puts the rotational mass on the mainshaft, and slows the rotation speed of the clutch by 3 or 4 to 1.

[dirty_rat]

Some of the real early Suzuki's had a crankshaft mounted cutch. Not many built or sold so probably almost no examples around any longer. The one I remember was the mid 1960's TM 250.

[Bill2001]

I'm wanting to say that the mid-60's Honda pushrod singles-- sport 50, 65 and 90-- had crankshaft mounted clutches. Some had a centrifugal oil cleaner in the center of the clutch. I don't recall the arrangement in the early twins. I don't recall what the other makers-- Bridgestone, Yamaha, Suzuki, Kawasaki, or the several European makers did. Though on the small displacement singles I'd suspect that a crankshaft-mounted clutch worked as flywheel mass to make the engine smoother.

My 2c.

[dirty_rat]

I almost forgot. The mid 1960's CZ's had a crankshaft mounted clutch. In fact, the early Suzuki TM 250 was an attempt to copy the CZ.

[go_hercules]

OP here: I never realized the Honda 90's had a crank mounted clutch. Rode them, but guess I never took one apart. And the CZ I didn't know either. Will look that one up for pictures.

[thrownchain]

The Honda Z 50 has a crank mounted clutch, as I suppose all the motors with a centrifugal clutch, auto shift set up, be the only way to get the clutch to spin fast enough to work correctly.

[Bert44]

Yes, Honda c90 and all derivatives have a crank mounted clutch. I'm restoring one at the moment. My MZ 250/2 ES has as well. Very similar engine to the CZ and Jawa. It makes for a slow gearchange as you wait for the motor to spin down on the up change.