i have a problem with my bike. when i start the bike up from cold the bike revs its nuts off but when i apply the throttle the bike slows down to about 7000 rpm. it wont idle. also sometimes when i add the throttle wide open the bike dies but when i let the throttle off it revs very high. ive stripped the carb and cleaned it thoroughly and the problem is consistant. there is no air leak anywere, all the seals are fine. if anyone knows anything please let me know. many thanks.

james, July 2010

m sounds weird are you sure you have the throttle slide in the carb the right way around.the cut out at the bottom of the slide should face the air filter.these ar 125s use a RRis system which means rotary and reed valve intake system so it may be worth checking the reed valves petals are ok as it may well run weird if they are not ok as it has both intake valve systems.

adam bike doctor, July 2010

it does either one or the other. its very tempremental. i have gone off the manual but the problem still here. ive looked in the fault finding part of the book and it says nothing about the symptoms the bike has.

james, July 2010

sounds like a carb problem. Have you put the slide back the right way round?
Sometimes Its worth investing in a new carb. I have had plenty of bikes that the carb and jets just wear out.
You didnt say it was running properly before? When did this actually happen? Suddenly?

bb, July 2010