Racing Engine

[Simonbt]

I still cant seem to get my engine to stop racing. Its a Suzuki GS125EZ, with a slide carb on it. The mixture screw is one turn out and the idle screw is all the way out (slow idle speed)

The symptoms are:

1. I cannot start the bike when cold without using some easystart
2. With the choke leaver up (i believe this is 'on') the engine is about 4-5000rpm (i cannot make this any slower. If i rev a little bit the revs climb but take ages to drop again.
3. When i push the choke leaver down the engine races loads, to about 9-10000rpm then drops to idle after a few secs. When i rev now the engine revs but drops slowly again.

I have cleaned the carb, nothing has changed from when it last ran except the float hights, but not much. (apart from being sat for about 5 years under a sheet outside). Also i have recently changed the piston rings (last week) and reseated the valves.

There is no smoke and it rides resonabaly well apart from having a bit of lag when you open the throttle to it actually doing anything.

Sorry bout the long post but this is driving me crazy

[Simonbt]

Almost forgot, If i turn the mixture screw out anymore the bike races even more and if i screw it in the bike just dies (screwing the idle screw in doesnt stop this)

[Guest]

Have you tried using the choke lever 'the other way'? If it's one of those oval-ended levers that just sticks out from the side of the carb I think it's down for on, up for normal running. Could be wrong but won't hurt to try.

Check the slide is in the right way round - the cut-out at the bottom of the slide should face the air filter. Also check the spring and throttle cable aren't snagging and pulling the slide up.

[Simonbt]

I've tried both ways (up and down) when its moving and it doesnt make any difference. Its not the slide either as it will only go all the way in one way round as the idle screw is fatter than the pin on the other side.

[DM]

If you have a leaking manifold than your engine will rev its bollocks off when started.

[alains]

try a test : run engine , and without touching anything else take the air filter off . if your revs change a lot this is a badly clean air filter . i think when you pull out the pilot screw if your revs go up this is because your mixture is too rich or your carb level in the tank is too high
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the worst day fishing is better than the best day working

[Simonbt]

Thanks for all your ideas. I've kinda fixed it now.... I moved the main needle down one slot and its solved the racing and the revs drop better now. It just still wont start from cold. Kinda annoying!

[alains]

leave the choke on after stopping engine
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the worst day fishing is better than the best day working

[Simonbt]

Im not convinced which way is 'on'.. Someone said up was on but it doesnt work like it is...