hey guys i got a 2003 derbi gpr 50 two stroke. everything is pretty much stock except the mikuni 26mm carb. When i try to take off, say rev real high say to 9k rpm from stop the bike boggles and hesitates almost to a stop. Its as if the engine is not getting enough fuel or too much fuel. If i rev to 4 or 5 from stop its fine. I'm pretty much a noob so excuse my noobiness if anything. Do you guys what the problem is or what i'm doing wrong? Also do these two stroke bikes take awhile to cold start? It takes me a good 2 minutes just to start the damn thing. thanks guys.
It sounds like it may be lean. Try upping the jet size and see if it improves. If it doesn't improve from richening, then start to lean it out a little.
That is a very large carb, if the engine is not HIGHLY modified for a 50cc and could also be your problem. The modified Derbi 50 in the Metrakit Mini GP is only 19mm, if my memory serves me right.
Well one problem is that you are using a 26mm carb on a stock bike. The pipe won't let the bike rev up like your suppose to. If you want to get the bike running right either get a performance pipe or get a smaller carb. Also drop your needle in the 26mm that may help.
Sounds to me like the Kinibler Pin in your Flux Capacitor is all out of wack! Try lubing your tire lights and then check your seat injectors and you should be "good to go".
Sounds to me like the Kinibler Pin in your Flux Capacitor is all out of wack! Try lubing your tire lights and then check your seat injectors and you should be "good to go".
That is a solution to a problem. It also can fix a persons sense of Humor. Maybe you should give it a shot??? Is comedy not allowed here? I thought if he laughed a bit the bike problems might not be that bad.
thanks for the replies guys, it was much help. i'll try tuning the carb and then update you guys on the status. An exhaust is definitely the next mod i'm doing to it.
If its not a lean or rich condition i would consider the possibility of reed fluttering at higher revvs. Try running stiffer reeds and see if the problem continues.
