HELP!! rev problems
Discussion
My bike is a 125 4stroke when is idling for about 10 15 mins and warm if I rev it up to 7 thou rpm and let go of the throttle it drops to 3thou rpm stays there for 1 min then slowly drops to idling speed of 1500 rpm.
Has anyone had this problem and hows it fixed?? My bike has a cv carb iv striped and checked it and all seems ok
I cant get the bike throw m.o.t because they keep saying sticky throttle cable but is not iv new one installed to be sure
Has anyone had this problem and hows it fixed?? My bike has a cv carb iv striped and checked it and all seems ok
I cant get the bike throw m.o.t because they keep saying sticky throttle cable but is not iv new one installed to be sure
Get some easy start and when it's idling spray it at the joints in the carb rubbers between the carb exit and manifold. If the revs rise you have an air leak.
Be careful not to get it in the air filter/carb INLET. You won't break it, but you might get a false reading as the easy start gets into the engine the "normal" way.
I hear you can use WD40 if you don't have ready start.
Be careful not to get it in the air filter/carb INLET. You won't break it, but you might get a false reading as the easy start gets into the engine the "normal" way.
I hear you can use WD40 if you don't have ready start.
Sounds like the mixture may be wrong, is the idle mix too week and you or someone has compensated by upping the idle speed? The idle speed sounds quite high. When you stripped the carb, you didn't do the fuel screw up tight did you, thinking it was a jet?
Try turning the idle right down and opening up the fuel screw a full turn. Rough rule of thumb, fuel screw (idle mix screw) would be about 2.5 to 3 turns out on a typical mikuni style carb.
BTW, I just bought a 450 enduro bike cheap as the carb was "knackered" "been rebuilt and it is kaput!"
Symptoms like you describe, and this was the simple fix, took me 5 mins! And three of that was modding a screw driver bit to make the adjustment!
Try turning the idle right down and opening up the fuel screw a full turn. Rough rule of thumb, fuel screw (idle mix screw) would be about 2.5 to 3 turns out on a typical mikuni style carb.
BTW, I just bought a 450 enduro bike cheap as the carb was "knackered" "been rebuilt and it is kaput!"
Symptoms like you describe, and this was the simple fix, took me 5 mins! And three of that was modding a screw driver bit to make the adjustment!
Edited by s3fella on Wednesday 29th June 19:39
roders89 said:
My carb has only one screw on it its mikuni bs26 doesnt matter wat way I screw it does nothing???
As above try turning it all the way in then about 2 full turns out. It certainly does matter, this is your air screw not to be confused with a simple idle adjuster. The more turns in the richer the mixture I.e less air, more turns out it becomes weaker. If it's not that I really would be surprised if you didn't have an air leak somewhere. The leak doesn't necessarily have to be at the carb, could be a base gasket for example.Edited by Yazza54 on Friday 1st July 06:00
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