Bike won't idle - dies on throttle

[sil3nt]

6 months ago got the gpx 250 serviced by a shop. Cost me $700 because it needed new float valves and air intake ducts (expensive). They cleaned/balanced and reset idle and mixtures.

Bike wouldn't idle at shop. No big deal i thought (being cold n all) and rode away thinking it would come right. Bike never really got used after that. A few rides here and there with not too much drama just awkward idle. Would be slow to return to idle and would be slightly erratic.

Now 6 months down the track the thing is worse than ever. Won't idle at all. Will start with choke but dies completely with choke off. Also dies with throttle. Haven't yet tried a ride down the road to clear its throat but may do soon.

What could this be?

I feel the work they did wasn't quite up to scratch but having left it since christmas I can hardly take it back and complain.

Quick search tells me dirty carbs? Don't see how carbs can get dirty after 400kms of use since they were last cleaned.

Any ideas/advice?

[The Singing Chef]

6 months ago got the gpx 250 serviced by a shop. Cost me $700 because it needed new float valves and air intake ducts (expensive). They cleaned/balanced and reset idle and mixtures.

Bike wouldn't idle at shop. No big deal i thought (being cold n all) and rode away thinking it would come right. Bike never really got used after that. A few rides here and there with not too much drama just awkward idle. Would be slow to return to idle and would be slightly erratic.

Now 6 months down the track the thing is worse than ever. Won't idle at all. Will start with choke but dies completely with choke off. Also dies with throttle. Haven't yet tried a ride down the road to clear its throat but may do soon.

What could this be?

I feel the work they did wasn't quite up to scratch but having left it since christmas I can hardly take it back and complain.

Quick search tells me dirty carbs? Don't see how carbs can get dirty after 400kms of use since they were last cleaned.

Any ideas/advice?

Had the same issue with my ZZR 250 91' Piece of shit, when I ripped the thing apart seemed there was a crack in the carbs and the butterfly valve on one side was bent slightly. And if you don't think they did a good job on it, then perhaps they left the carbs dirty and is what has caused your problem?

[slofox]

I replaced a carb on a Hillman Minx years ago, with a "reconditioned" carb. Turned out to have lots of little metal bits floating around inside it from where some bits had been drilled out. Took months of pulling to bits, flushing out and reassembling to fix it. It used to bahave in a similar manner when the swarf got stuck in the holes.

I'd take carbs apart and check insides are clean - specially jets etc.

[sil3nt]

Fuck what a shit day. It's called the fucking reserve switch. :bash: :Oops:

That solved the bike dying on throttle part. Apparently bikes need gas when you open the throttle.

Bike is still slow to return to idle. Reving to 5000 it falls to 2000 as normal then it hangs around there for awhile before returning to idle which is 1200-1500 depending on the idle screw. This is from warm.

From cold it takes longer to return to idle.

Took it around the block a few times and it ran fine. Just that slow return to idle is annoying me a bit.

Bike was running mint until I decided it better have a service!

[FJRider]

Clean and re-lube the inside of the throttle cables, and lube all throttle controls (handlebar, and carb linkages)

[sil3nt]

Clean and re-lube the inside of the throttle cables, and lube all throttle controls (handlebar, and carb linkages)Thanks will do.

[FJRider]

Thanks will do.

The carb linkages on older bike often get wear points, that can stick, or restrict throttle return. You can often feel them if you move the linkages with your finger. A nail file can smooth these out.

Weak/stretched return springs often cause lack of full (quick) return.

[sil3nt]

The carb linkages on older bike often get wear points, that can stick, or restrict throttle return. You can often feel them if you move the linkages with your finger. A nail file can smooth these out.

Weak/stretched return springs often cause lack of full (quick) return.The choke has never actually stayed on since I have owned the bike. Have always had to hold it in place otherwise it returns to its starting position. Forgot to ask the shop to sort it. Probably need new springs on both sides of the carbs.

[sil3nt]

Ok just went and looked at where the throttle thingy ma jig on the carb. It snaps back instantly when you let go of the throttle so must be an internal thing. And there is no way in hell i am pulling the carbs off again :laugh:

[FJRider]

The choke has never actually stayed on since I have owned the bike. Have always had to hold it in place otherwise it returns to its starting position. Forgot to ask the shop to sort it. Probably need new springs on both sides of the carbs.

Thats not always a BAD thing. But check the action of the choke to see if it fully closes and opens. Again ... some older bikes don't fully open (or close) ... and remain partially open. thus running partially rich, and using more fuel than it should. AND ... not letting it idle properly.

A lot of fuel issues can be traced back to the choke action.

[Zerker]

Good luck with it Sil3nt, I'm still keen to come have a look at it today, so let me know if thats all good.

[Phreak]

If the revs are running up and down (even if only slightly) at idle, ie 'hunting', it's a mixture issue. I'd say the workshop that serviced it haven't quite got the setting right. My bike was doing the same after a service a year ago or so, I adjusted the mixture settings till I found a nice flat idle (with the engine at operating temp). Can't remember if 'hunting' means slightly rich or lean though... Good luck!

[actungbaby]

[QUOTE=sil3nt;1130316793]Fuck what a shit day. It's called the fucking reserve switch. :bash: :Oops:
i had gsx 450 with the slow to return to idle damm thing whould go into corner like it made me faster though

I was told at the time it chould be air leak between airbox and the carbs

as this was what was worked on b4 it started doing this thats why work backwards on a problem you chould try checking how its sealed around the airbox if you can

u can ride them well i just never worked it out and rode it down south and alot like it
Somedays was better than others i found letting clutch out bit knocked it back well mine whould rev high at lights so is bit diffrent to your problem.

also chould try just turning tap of on tank and undoing drain screws on the carbs bowls should be near bottom of the carbs dont get wrong thing and ajust the mixtrue though