Modern Vespa

I have always been a little disappointed with single spring clutch on my SF bikes. The clutch works, but always seemed to drag a little. Knew of the PK XL clutch swap-out that pretty much solves everything, but I was trying not to spend $115+ for all the bits and pieces. Not to mention a whole clutch unit that has very little in common with the one it is replacing. Even the friction plates and steel disks are a different thickness.

Enter Stoffi and their new clutch conversion. Basically replace the single unit with the Stoffi unit which has 12 small springs arranged in a circle. Kind of duplicating the PK XL unit but without having to buy anything else except the spring. Supposedly good for up to 18hp. Can remove alternating springs for lighter action. I just put it in with all 12 and it feels like the 'reinforced' - strength single spring. Don't need vice-grip hands to pull the clutch.

Boy, what a difference! Clean separation, no dragging at idle, easier shifting between gears (I am guessing because of cleaner separation). It feels like it engages smoother, more progressively and the action feels smoother also. The even pressure all around makes it soooo nice. I have been using it for a few months now. Price when it was first available was just about $66. It has gone up since, ($73 last I checked), not sure if its because of demand, or exchange rate.

Crimaz is following suit and I just purchased one. Much cheaper at $40. Will report when I get it.

If anyone else has tried the Crimaz unit, let us know how it is. I guess Pinasco makes one also, but for how much they want ($147 as of this writing.... cough, cough,.gag...) you could go the full PKXL route with a little left over.

Gave you a thumbs up for this one. Man I needed to hear about this 6 months ago when I had the build from hell burning clutch plates.

Are you using the stock cover still?

Thanks MJRally.
Yep, still using the stock cover, lever, and pushrod. Another reason I was trying to avoid the whole PKXL clutch swap. I have heard some people have clearance and other issues swapping out the clutch. Having to add cover spacers, grinding clutch covers for clearance, and what-not. Too much dain-bramage for me...

I should also add that well before the Stoffi spring change, I switched to a 4-plate clutch. I had issues with the 3-plate clutch slipping under power, even with a reinforced single spring. The 4-plate clutch did not slip but it dragged at idle like crazy! And shifts were harsh because of the drag.
Put this spring in, with the 4-plate and ..... aaaaahhhhhhhhhhh......

New wave type spring from Polini for small frame single spring clutches.
Only about $13!! When it becomes available, I think I will have to try it.

They have full clutch kits with this new spring also.

Good info ... the clutch on my smallie is about due for a re-cork. I'll definitely give the spring upgrade a go.

Good stuff right there! Good timing too, as I'm about to order all new clutch rebuild parts for my smallie w/ Polini 130; so was going to do some searching on what way to go (without pkxl route)

how fortuitous... i was just getting ready to jump back into the PK here in a bit. i look forward to the updates!

-g

Thanks for your post.
I just place an order that Polini spring!

That looks like a winner, not sure how I missed this post earlier.

I got one of those Stoffi clutch springs for my Sears rust badge and its a huge improvement over what I had going on before. Also went from 3 plates to 4 plates in the clutch too so not sure if that was a factor for a easier clutch pull in. The sprigs really even out the force inside the clutch vs the one big spring. To me it now feels more like a large frame cosa clutch but not as smooth as a pk clutch arm. Maybe I need to adjust more to get there but its fine now.