I’m stupid and can’t understand my clutch

Doctor IcroWave /

I have a 1977 Puch maxi Newport. I’ve messed with it a lot over the past couple years. Put in a 70cc low comp treats kit, 15mm carb, boss pipe(I understand this isn’t the best pipe), cleaned up bearings, new air filter, set gearing to 16 40 for a more comfortable top end. I set my timing using a light to 16-17 degrees before TDC.

So I’m having trouble with the clutch where it revs up a little too high to start going and it’s pretty slow to accelerate from the stop. Not bad but I think it could be better. It engages fully around 25 mph and goes up to around 40. At one point I had blue springs in and it felt pretty good. It didn’t rev so hard to get going. It was more gradual. But I wanted to keep adjusting so I use ESO springs and have tried many times with super stiffy and turning the screws various amounts. Now it doesn’t feel so good. Just seems like something that I’m not thinking of is impacting performance. Any advice? (edited)

Re: I’m stupid and can’t understand my clutch

What fluid are you using? How does the friction material look?

Re: I’m stupid and can’t understand my clutch

If you’re sure it’s the clutch (like you’ve double checked for air leaks and confirmed your timing and there are no changes to carb/pipe/filter that might affect jetting), then it could be the spring tension is just too high and you’re slipping g too long. Or it could be that the tension on the arms could be so different that they’re engaging at different times — I got sloppy with that once and ended up with very different tensions on the two arms, which affected performance until I corrected it.

You know about using a fish/luggage scale to set the tension, right? I’m at about 30 lbs, which seems to work pretty well.

Re: I’m stupid and can’t understand my clutch

Matt Mahloch -- MBM Customs /

What you’re describing are the symptoms of too much slip for the amount of power you’re making. Dial back the slip and it’s as good as it’s going to get. If you need more low end get a bigger carb and intake or a low end pipe.

Re: I’m stupid and can’t understand my clutch

The clutch arms need to be lightened a little and balanced as well. How are you measuring your spring tension for each arm? A fish scale can help with that if you dont have one.

Re: I’m stupid and can’t understand my clutch

Doctor IcroWave /

This is what my clutch looks like. Right now my springs read at about 30 pounds. I’m debating between using F fluid or 0W-20. Right now I have the synthetic 0w-20 in. What is the difference between lightening the arms and increasing the spring tension? Both increase slip right ?

Also I have 80 jet in with needle 2nd from top with 15mm bing clone. I’ve had some success with this and the power output seems to be pretty good but I just wanted to see what other people think of it. (edited)

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Re: I’m stupid and can’t understand my clutch

roots to wings /

Im finding different bikes run diffferent with the same springs and tension. 30 is too high for blues but good for stiff, but your pipe is junk. Estoril sidebleed, proma circuit, mlm cali, or cranks. 80 might be too high for bing 15. I use 78, but I can see how an 80 could work.

Re: I’m stupid and can’t understand my clutch

Yes lightening and spring tension are what us needed for the proper balance. 30lbs is too much. Should be less than 20lbs. On the wiki it mentions 15lbs spring tension but closer to 20 is pretty much perfecto. I know folks lightening clutches down to about 7.5g. Mine are balanced close to 9.5 but I plan to lighten them a bit more.. Key is that they weigh the same so with the balanced tension they come out evenly allowing slippage but a hard grab once engaged.

Re: I’m stupid and can’t understand my clutch

Dirty30 Dillon /

> Doctor IcroWave Wrote:

> -------------------------------------------------------

> This is what my clutch looks like. Right now my springs read at about 30

> pounds. I’m debating between using F fluid or 0W-20. Right now I have

> the synthetic 0w-20 in. What is the difference between lightening the

> arms and increasing the spring tension? Both increase slip right ?

>

> Also I have 80 jet in with needle 2nd from top with 15mm bing clone.

> I’ve had some success with this and the power output seems to be pretty

> good but I just wanted to see what other people think of it.

Looking at this, you have your clutch springs tightened and they probably cannot swing open enough to catch the clutch bell, due to the spring binding.

Re: I’m stupid and can’t understand my clutch

Also I would like to mention I am running the eso springs and like them a lot.

Re: I’m stupid and can’t understand my clutch

roots to wings /

@jay, what tension on eso if the shoes aren’t lightened?

Re: I’m stupid and can’t understand my clutch

I have the tension at 19lbs. I may keep them around that even after I lighten the arms a bit more. Still dialing things in on the bike, but I have good slip and it grabs hard at about 20mph when the pipe hits. I'm in the process of doing a reed setup so I can even out my rpms a bit better.

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