Very high idle after cleaning out carbs

[crumbobly]

Hi Guys,

Well firstly my bike is a 1991 Suzuki GSF 250 Bandit,

And i decided to give the carbs a bit of a clean as i had a slight hesitation at around 4-5k rpm.

Pulled them off and dismantled them and found alot of reddish metalic particles in the bowls. (rust from gas tank???)

Any way took all the jets out and soaked in cleaner and cleaned up all the passages. Made everything looking shiny and new taking care not to get cleaner on the rubbery bits.

Reassembled and put back on bike.

Problem now is the bike idles at arround 7000rpm and will not drop.

I was running out of sunlight so had to stop for the night but can anyone give me any suggestion as to why it would be doing this???

Probably gona check for air leaks and the throttle cable tomorrow but is there anything else?

Any help appreciated.

[racefactory]

You must have an air leak.

Inlet rubber not mounted properly is the main one. Maybe the inlet manifold blanking stub not sealed up. Probably just take them off and fit them back carefully again and chances are it'll be gone.

Good luck.

[MSTRS:Me]

Do you have play at the throttle grip? A common cause of high idle after removing carbs is dislocation of the throttle cable (outer), at the carb end.

[Latte]

Do a search for "high idle 8000" - thread from a guy called cbfb (I think) just went through the same scenario, lots of good info in there (as well as the above here).

[cbfb]

Do a search for "high idle 8000" - thread from a guy called cbfb (I think) just went through the same scenario, lots of good info in there (as well as the above here).

Aye that I did. Bit of deja vu there.

Crumbobly this is the post that hiss is on about.

On mine it was most likely the throttle cable getting stuck on something so have another look, but I did have an air leak although it shouldn't make it go that high.

Does yours go straight to 7k and stay there or does it gradually increase as the bike warms up?

[crumbobly]

Thanks guys i had a bit of a play today and MSTRS was bang on the money, All i had to do was give myself a we bit of slack in the throttle cable and she was back to normal.

I can say after a clean of the carbs i feel like i have a fair bit more power especially in the top end, but i still have a bit of a flat spot at around 6-8k rpm.

Not really noticeable when riding so im not that fussed but in neutral if you fang the throttle it wil shoot straight up to around 6-8k rpm and hesitate for a bit then straight up to redline.... 16-17k rpm

Im assuming thats not normal...

However if you are relatively smooth applying throttle there is no flat spot.

Any ideas on that one?

[cbfb]

Maybe an air leak?

[FJRider]

With no load on the engine ... to change fuel flow from idle to red line requirements ... may mean a hesitation even with a fuel pump. Unless it is a high pressure type fuel pump ...

[MSTRS:Me]

Thanks guys i had a bit of a play today and MSTRS was bang on the money, All i had to do was give myself a we bit of slack in the throttle cable and she was back to normal.

FIGJAM....

... i still have a bit of a flat spot at around 6-8k rpm.

Not really noticeable when riding so im not that fussed but in neutral if you fang the throttle it wil shoot straight up to around 6-8k rpm and hesitate for a bit then straight up to redline.... 16-17k rpm

Im assuming thats not normal... No it's not

However if you are relatively smooth applying throttle there is no flat spot.

Any ideas on that one?

I'm thinking that just maybe your floats are set slightly out and the fuel level in the bowls is a tad low.

[notme]

With no load on the engine ... to change fuel flow from idle to red line requirements ... may mean a hesitation even with a fuel pump. Unless it is a high pressure type fuel pump ...

Er...is it not gravity feed?

[FJRider]

Er...is it not gravity feed?

You tell me ... and I DID say "even with a fuel pump"

[cbfb]

You tell me ... and I DID say "even with a fuel pump"

Aye, tis a gravity feed

[crumbobly]

FIGJAM....


I'm thinking that just maybe your floats are set slightly out and the fuel level in the bowls is a tad low.

Thats one of the things is didnt touch as i didnt know the correct height, can anyone point me in the right direction and points to measure from (im guessing from bottom of float till edge of carb body)

And on that note a proper manual for this thing would be good. All ive managed to find is a gsx250f manual and im not sure what is the same and what isnt.

[cbfb]

Thats one of the things is didnt touch as i didnt know the correct height, can anyone point me in the right direction and points to measure from (im guessing from bottom of float till edge of carb body)

And on that note a proper manual for this thing would be good. All ive managed to find is a gsx250f manual and im not sure what is the same and what isnt.

LOL look at the post I started that I sent you, Ducatilover recently posted a link to a site giving instructions on this.

Nah you're out of luck with the manual, that's the best you're gonna find. the GSF400 one is good for anything chassis-related tho.