CR125 tuning question

Jon Betts · Posted: Sun Jul 22, 2001 6:17 am Post subject: CR125 tuning question

Stock CR125 with 36.5mm keihin carb. with the kart on the stand when the engine is revved up the rpm comes back to some higher idle then after a few seconds the idle drops? I also notice that during the higher idle there is no sign of gas spitting from the carb but as soon as the idle drops to the lower level I can see gas spitting from around the bottom of the slide?

Thanks JB

Matt Kull · Posted: Sun Jul 22, 2001 7:55 am Post subject: CR125 tuning question

Do you have a return line from your carb to your fuel tank? Either that or check the float level.

[ July 22, 2001: Message edited by: Matt Kull ]

Jon Betts · Posted: Sun Jul 22, 2001 3:38 pm Post subject: CR125 tuning question

yes I have a return line, are you thinking that the float level may be to low causing starvation at hi revs then it takes a few seconds to give enough fuel at low revs causing the rpm drop?

John Neilson · Posted: Sun Jul 22, 2001 4:14 pm Post subject: CR125 tuning question

It sounds like the idle stop screw is just holding the slide at the idle/main transition. Try lowering the idle screw about 1/4 turn and see if the return to idle is cleaner.

TJ Garner · Joined: 22 Jul 2001 Posts: 14

try taking the spring out of the carb. and pull it apart I read about this in a dirt bike book, and I had the same problem, and when I did that it seemed to solve it so I hope this will help you