8 replies to this topic

[BenC1980]

Hi

just wondered if someone can point me in the right direction, i have an 09 290 sherco, and the revs started falling really slowly and holding a high idle, throttle cable is fine and bike rides and start's perfectly.

obviously its the carb but what could be the cause? Throttle slide appears to snap shut ok. I dont have much time between now and weekend to get it fixed!

Really appreciate any help.

thanks
Ben

[copemech]

BenC1980, on 27 April 2011 - 10:05 PM, said:

Hi

just wondered if someone can point me in the right direction, i have an 09 290 sherco, and the revs started falling really slowly and holding a high idle, throttle cable is fine and bike rides and start's perfectly.

obviously its the carb but what could be the cause? Throttle slide appears to snap shut ok. I dont have much time between now and weekend to get it fixed!

Really appreciate any help.

thanks
Ben

If you are indeed sure slide and cable are ok, then I believe the first thing would be to clean the carb well, specifically the pilot jet and circuit, as this will cause slow return and floaty idle.

If you break the carb over a clear glass or olastic container, you might be surprised what comes out the bowl.

Let us know how you get on before worrying about other potential problems.

[TooFastTim]

copemech, on 28 April 2011 - 12:39 AM, said:

Let us know how you get on before worrying about other potential problems.

Alternatively you have an airleak. If the carb doesn't show up anything check the rubber hose between the carb and the reed valve.

[copemech]

TooFastTim, on 28 April 2011 - 01:19 AM, said:

Alternatively you have an airleak. If the carb doesn't show up anything check the rubber hose between the carb and the reed valve.

Yes, but at the same time of doing the carby, defects here should be fairly obvious, even though the manifolds seem fairly rugged and durable.

Problem with all this is, based upon a number of reports, I am giving 2-3 years life expectancy on the standard crank seals when running the alcohol induced fuels. Being a '09 bike, I would not rule it out, yet would not go there quite yet! Hopefully he can get a "proper" cleaning done. There are other recent refs to this procedure. We need to get Neo to produce a training video using his spare carbs! Not like I don't have two sitting in front of me! Ha!

[BenC1980]

yeah im fearing the mains, i always do fear the worst but the bike has done very very little work, and the idle is abit "floaty" When the idle is high the slightest touch to the air screw and it drops to a classic 2 stroke slow idle (just how i like it) ill pull it apart and report back thanks for all the info so far!

Its the only time ive not cleaned the bike between rides so im hopeing its just muck in there!

[BenC1980]

can anyone tell me the base settings for the idle mixture and air screws please, cant find them anywhere.

[BenC1980]

fixed!

found a blocked jet, not sure what one seems ok now.... just cant find the base settings for screws.

[copemech]

BenC1980, on 29 April 2011 - 11:47 AM, said:

fixed!

found a blocked jet, not sure what one seems ok now.... just cant find the base settings for screws.

Varies with the pilot jet, but about 3 turns out on the fuel screw is normal, idle speed set to suit.

[BenC1980]

copemech, on 29 April 2011 - 02:45 PM, said:

Varies with the pilot jet, but about 3 turns out on the fuel screw is normal, idle speed set to suit.

thank you )