gilera rcr 50(derbi senda) problems

[matyboy1]

hi i have a gilera rcr 50 which im having problems with it has a race exhaust and is derestricted it accelerates and pulls well in 1st,2nd and 3rd to like 35mph then bogs down in 4th,5th and 6th and gains very little speed,im thinking that the carb needs adjustment.does any1 no the setup for the carb eg idle set screw,idle screw etc any help would be much appreciated thanks

[dobby]

did you fit the exhaust yourself?

was there a restrictor in the front of it still?
silly question i know but iv worked on a few sendas before where people have fitted it themselves and forgot to remove the restrictor plate...

also is it jetted propperly for the exhaust

has this just occured or has it always been like it?

might all seem sill questions just trying to eliminate some ideas

[matyboy1]

the exhaust was allready fitted when i got its a mk exhaust,i coudnt tell you if its been upjetted to suit at the moment its got a 75 main jet in also its using quite a lot of petrol at the moment

[dobby]

i am presuming that it has been derestricted properly

try down jetting to a 70 main jet and putting a 12 tooth f/s on if it hasnt already got one on...

i worked on a few with race exhausts on leo vince a metrakit exhausts on and they have run ok on a 70 main jet...

try the jet first and let me know how you get on with that

[matyboy1]

its got a 14 tooth front sprocket and a 45 rear dont no if this has anything to do with it beeing so slow.

[dobby]

im not sure what size standard have but last 2 iv worked on had 12t f/s try changing the jet to a 70 see how you get on chap