Idle problems - Alternating between 4000rpm and stalling?

[no_8wire]

Hi.

I just bought a 92 GSX400 from a dealer.
I had previously identified that the bike was idling high (3000-4000rpm) and it was agreed that the bike be repair prior to purchase.

When I picked the bike up today I was assured that problem had been fixed and it started up ok so I bought it and rode it off.

However on the way home the bike would alternate between idling at 4000rpm, or simply dropping until it stalled.

I tried to control it via the choke switch however it had little effect.

The bike would sometimes die as the revs were to low, however when you restarted the bike it would jump to 4000rpm.

I am going to take it back to the dealer as it was supposed to be repaired prior to purchase, however what could cause this problem?

Stuck choke slide?

[paturoa]

Could be a bunch of stuff. Often this sort of thing is carb related, worn, partially blocked pilot or idle bits etc.

[motorbyclist]

basically they didn't do a proper job of fixing it the first time; carby needs a proper and thorough clean out

[ducatilover]

Could be a dirty carbs, but I would be looking for an air leak on the intake side
Good luck mate

[Squiggles]

My monies on an air leak

[motorbyclist]

good thinking

+1 for the air leak, but carbs are still a likely player

[no_8wire]

So if it were an air leak -
Tube to the ear and test all joins after the throttle plate?
TB-Carb, Carb-runners, runner-head?

[Laava]

Yep or a gentle squirt with engine start. If it is sucking anything in, it will immediately rev up. Just don't do too much or at the rear of the carbies.

[no_8wire]

Thanks for all the advice, but hopefully Im not going to have to do anything about it myself as the dealership is been really good and is going have a look at it. Just need to drop it off while I get their loan bike.
:yes:

[no_8wire]

Turns out it was a problem with the carb. The dealer has it fixed and idling smooth. Time to go and enjoy it!

[motorbyclist]

basically they didn't do a proper job of fixing it the first time; carby needs a proper and thorough clean out


My monies on an air leak


good thinking

+1 for the air leak, but carbs are still a likely player


Turns out it was a problem with the carb. The dealer has it fixed and idling smooth. Time to go and enjoy it!

I'll be having that money now, squiggles :p

:wari:

[Squiggles]

good thinking

+1 for the air leak


I'll be having that money now, squiggles :p

Maybe when you earn it ;)

[motorbyclist]

Maybe when you earn it ;)

I'll go to work when I goddamn have time god dammit!

that and there's work for me to do.

now if only the two events would coincide once in a while.....


besides, do you not understand how a bet works? now, all your monies or a pound of flesh!

[MickDastardly]

Hi, did the dealer explain what had caused the problem in the end? i've got the same problem.

cheers

[motorbyclist]

ohhhh that's right! I forgot squiggles owes me all his monies!

[no_8wire]

They ended up fixing it by cleaning the carb and jets. Apparently there was some dirt/ blockage problems (so rev up was caused by the idle screw been turned up so the bike ran when partially blocked and when it unclogged reved up etc...)

Thats what they said anyway...