1980 Puch Magnum II
70cc DMP kit
Proma Circuit pipe
14mm Bing/14mm intake/no air filter
18 x35 gearing
I've done some searching on the forums and using Google and have come up with some useful information, but I thought I'd throw this out there to see what you all think.
The issue is that from a dead-stop, if I open up the throttle slowly my entire bike shakes quite violently as it revs up (a riding buddy has said it's visibly noticeable). Once it shifts to second gear, all is well. However, if I throttle up a bit harder (open up to about 40% throttle quickly) from a dead-stop, the bike doesn't shake at all.
When the bike is actively shaking, I'll let off the throttle completely and open it back up again. About 75% of the time, the bike will shake again while still in 1st gear (it will always shake if I open the clutch slowly at this point). Occasionally, it will rev up without shaking and shift smoothly to 2nd gear. Either way, once the bike shifts into 2nd gear, all is well.
I recently had a pair of new clutches installed (many thanks to Chris Paz and Hot Rod Todd for that) and I'm afraid this behavior is causing the clutches to wear out. The pair I have in there now replaced a previous set which had shredded the clutch lining. It's notable that the previous set of clutches also did this same behavior, so I'd like to assume that this could have been the reason why... or at the least a contributing factor. Also of note, the clutch has been flipped so the 2nd gear engages later.
What do you all think?
Pic of the bike:
Pic of the clutches (pre-install):