Hi guys, hoping someone can help me with this before my head explodes I have a 1999 piaggio zip 2 stroke standard bike. I bought it as a non runner as it had been stood for winter. I got it going very easily. But now have an issue. I took the bike out for the 1st ride and it wouldnt take full throttle,would just bog out at 1/2 throttle almost feeling like the engine was being starved of air/fuel.and also after a bit of riding it felt like the throttle was sticking, and running really roughly. I decided the best way forward was the obvious things, replaced the spark plug cleaned the carb ( it has a 60 jet in it) checked the air filter which was fine. But still no better. I also checked and reset the mixture screw to all the way in then back out 1 1/2 turns, and also checked the throttle cable which is fine So i decided to go a bit deeper, i checked the autolube which is fine, i stripped the head and exhaust and decoked, and even went as far as putting a new piston and rings in, still no good So my next idea was transmission, so i investigated this to find the variator rollers where completely knackered, broken and square. So i hastely ordered a new set of rollers. However after thinking about it last night i realised i didnt check the weight. The rollers that came are 3.0 grams. I thought id bang them in and give it ago although they felt alot lighter than the ones i was replacing. Its now worse than ever. So my question to you guys is are these rollers too light for a standard bike? And if not any other ideas what could be the problem? Sorry for the essay but i know its easier for you guys if you know all the details. Please help me.
had a similar issue with a zip SP...it was the mixture screw that needed adjusting. Ran fine after that
3 gram is WAY WAY WAY WAY to light on a standard zip. My 05 zip ran 7-8's can't remember which one! The idle skrew will be roughly 3 1/2 turns from fully skrewed in. Check your reeds/manifold while you're at it. Is it completely standard ?
Hi and thanks for the replys, yes its completely standard, the previous owner said he hadnt touched it. I had the manifold off and have checked. Would too light rollers cause this bogging?
Yes they can do. It's not bogging through it's where the bike can't get momentum to get going from where the rollers are far to light, If I'm correct. I'd check for air leaks too. But those rollers deffo aint helping. Is it de-restricted ?
No mate not derestricted as far as i know i must admit im starting to think it could be an airleek from somewhere just trying to work out where from have checked the inlet manifold but it just feels like its starvation etc as it will completely die at full throttle. My head hurts lol.............
if its not derestricted it should have either 53 or 56 jet in to best of my knowlage, does it have brass plate still behind airbox? you cleaned carb? and start it up and spray wd-40 around manifold area and see if the engine revs change if so you have air leek
I to have the same scoot as you but its far from standard, Someone has pissed about with it by the sound of it, standard Zip RST rollers are either 6.8g or 7.5g, 3.0g are the lightest you can buy for this scoot's variator size (I bought some as an experiment, what a waste of time) all that will happen is the engine will rev its balls off and increase ground speed slowly as the belt/clutch have to deal with the over revving. The thing that will be causing bogging is incorrect air fuel mix, resetting your carb to factory will be a little bit of a mission. To me it sounds like an air leak, as I've had similar problems when the scoot was standard. The rubber hose from the carb to the airbox had perished and split allowing to much air in at anything over 1/3-1/2 throttle. So that got replaced and the problem went away. Several weeks later its started again, turned out the rubber manifold between carb and engine had cracked so that got replaced. It was fine for months after until the spanners came out and the standard stuff went in the shed...
