Hopefully this is in the right place? I'll try get this in words. The bike is my sons zip50 cat 2000 model 2 stroke. On the road now for about 300 miles odo showing 10k. Was derestricted (washer out of variator and restriction out of pipe with cat pipe thing blocked) it ran great. Just over 45mph ish. Decided to fit a tecnigas trek pipe after reading a few reviews, Jetted up to a 70 main and fitted 5.3g rollers ran even better at 55mph plus. Mixture good and acceleration brilliant. Happy days. (Also took the brass plate thing out of carb) Now about 3 weeks ago, he starts coming to me saying it wont pull away from the lights. Just sits and revs, then eventually when it gets to a certain speed it takes off like it should. So i read a few inconclusive posts that point to the rollers..........hmmm only fitted a few weeks ago but check them anyway along with the belt. Belt shows out of spec but rollers fine. Must be belt slipping. Buy and fit a new one. Now, the acceleration is part back, i mean its rideable and seems to fly up to about 35 then crawls and peaks at about 40mph. Definately a good 10-15mph down on what it was! Things tried so far. 1. Removed and cleaned clutch shoes and bell- No change 2. Fitted a white Naraku 1000rpm contra spring- Made it worse, acceleration very poor till later in revs. Put standard contra spring back. 3. New plug- No difference 4. Compression test- showing about 90psi +/- 5psi Tad low but i would have thought poorer slow running and starting, i may be wrong. Any ideas are more than welcome as am sick of taking the bleeding thing apart now!
Have you checked the belt is getting to the top of the front pulley. Put a bit of paint or other marker like felt tip on the variator inner faces and see if the belt rubs it off.could meed a stronger spring to help it up.
I'll give that a try mate over the weekend. Had all the clutch bit apart and it's all well lubed and i might try different clutch springs. But a dab of summat on the variator is a good idea. The belt i fitted is a direct replacement Dayco, same make and size as one i took off only without the Piaggio logo next to theirs.
I think all that stuff in the drive line should be clean and free of any grease oil and other slippy stuff.if its "well lubed" it could be enough to cause a contamination on the belt and slippage. Whats the engine revving like at the top end.if its revving its nuts off and slow on the go then ide say slippage..if the revs ain't there..timming..carb?..everything was ok but now has SLOWLY faded,but nothings broken. Welcome to the "pissed off with removing bits and panels" club.
hi I would reduce the weight of the rollers by a couple of grammes (total weight of the six).If you do this and it's better but still not right, carry on ! The transmission is not letting the scoot get into it's power zone. Also, check the belt slip at the variator. If the belt is so tight in there that there is no slip (the clutch is spinning on tickover) then you need to shim the variator with a washer so it slips more. Top perf make these washers in a pack - a range of thicknesses- and this helps the take off. Belt width varies wildly, and you need a little bit of slip.
Well, got a bit of time this evening to have a play about with this! Followed some of the tips above. Off with the side cover and dabbed a bit of paint on the outer edge of variator. Up the road and re-check. Yup the belts doing it's full travel. So that was all good. Next up fitted some Naraku 1000rpm clutch springs. Back off up the road and it became apparent it was 'shifting up' out of the optimum rev range. Result! Now in the abscense of any lighter rollers it was time to experiment. Found the next size up drill from the roller centre size, dropped out the rollers and drilled 3 of them out. (Didn't want to completely render the scoot useless as it's still in daily use ) Result no2! It flew, stayed in the right rev range and held an indicated 50 odd mph on the speedo Thanks for allthe responses and tips guys. It is getting there!
there's a lotta clever b,stards out there.stock rollers drilled.digital scales time i think when i whip my rollers out next time.go too light..chemimetal repack.
