2008 Jonway 50 stuck doing 20

[phillipmalecot101]

Hi, I bought a 2008 Jonway 50 off of craigslist with only 600 miles from an old guy who couldn't ride it anymore. Scooter had issues from the day I took it home. Previous owner drained the gas and has let it sit for about a year and half before I took it home. I took the carb off cleaned it real well, through some gas in it and drove it home. The issue I discovered on the way home is the same issue i'm still having today and I can't figure it out. It runs fairly strong and normal up until about 20 miles an hour, I have to baby the throttle to get it there and anything past where it feels comfortable it dies on me and I have to back off and start again. The longer I ride it the louder this jangling sound gets and I can't figure where its coming from. I've replaced the carb all together with a larger unit and replaced the cdi with a 150. Any help would be appreciated, I'm fairly good with the mechanical operation of these scooters but not great at diagnosing whats going on. Thanks for your time, I will check this often as I'm trying to get it running well for tomorrow.

[kagetenshi]

First check valve lash. Second check jetting. Third check the belt. Fourth check to make sure the starter Bendix isn't hanging on the running gears. Just my 2 cents.

[kagetenshi]

Jangling in the cvt region usually dictates starter Bendix interference.

[arkie]

Check also your flywheel. I had one that wallowed out the key/keyway on the crankshaft. It made a jangling sound and as the timing was never right at that point it was slow.

[niz76]

+1 on the valve adjustment and also +1 on tuning the carb with the proper main jet. It seems we're reading a lot here lately about folks just buying new carbs and throwing them on with no tuning. Not saying that's what happened here, but it would seem slim chances that a carb happened to come with the exact perfect main jet for your scoot... Gotta tune em!

[phillipmalecot101]

Thanks for the replies, first thing I checked when I got home was lash so I'm set there. Belt seems good as well as Bendix. Carbs probably a bit lean with a 63 but it runs to 40 no problem and then dies out and have to try to keep it up again. After riding tonight I'm almost positive I'm getting slippage in the cylander. Since it has so few miles and I still haven't changed the oil on it I bet that's where the problem lies. What do you guys think?

[niz76]

So it's not stuck doing 20mph and actually does 40? Dies out, keep it up again?? Slippage in the cylinder???

Does the scooter literally stall after driving it WOT? Where's the jangling sound coming from? It sounds like a bad carb tune but really hard to pinpoint exactly what you're describing...

[phillipmalecot101]

Sorry I'm not being clear, when I first start to ride it can run to 35-40 but the longer I ride the harder it is for it to hold speed and it's not capable of reaching those speeds after a couple miles, can't go faster than about 20. By slippage I mean the rings because it's not broken in with the correct oil. Just changed it tonight for the first time. Could be a bad tune but it's running with the main jet that came with it, and the clip one richer than standard on the needle. Could I be having power issues with the cylander with old oil and the engine still breaking in?

[niz76]

With 600+ miles it's probably well broken in. Oil change is def a good idea especially if it's a used scoot with unknown history. What was the valve lash set at? They do tend to tighten up a bit as the engine heats up and expands...