misbehaving revs

tatman · Derestricted Danger Joined: 20 Jul 2004 Karma :

I have a twin cylinder 2 stroke. I have a problem where if I open up the throttle when it's idleing the engine sputters and dies. If I work the revs up gradually and then close the throttle, the revs take ages to return to idle.

If I adjust the idle screws to make it idle at 3000 instead of 1000, neither of these problems occur but that's only covering up the problem rather than fixing it...

Jrod · Page 3 Girl Joined: 02 Aug 2004 Karma :

Sounds like its being flooded when you open the throttle, Maybe the mixture needs adjusting ?

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

I would be inclined to say that it is running lean, but possibly from an air leak from after the carbs. Check the mounting rubbers for the carbs for signs of cracks. Failing that the main bearing seals are also a major source of air leaks.

All the best

Keith
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stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

I'd agree with kickstart, sounds like a leak in the inlet manifold area.

With the engine at tickover (and before it gets too hot...fire risk), spray some WD40 over the area between the carb and the engine. If the revs increase when you do this, you have an air leak.

What sort of bike? could be a problem with the reed valves if it has them.

What do your plug electrodes look like (colour, signs of pitting/scorching?)
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tatman · Derestricted Danger Joined: 20 Jul 2004 Karma :

It's a Kawasaki KR-1 250cc 2-stroke. The rubbers between the carbs and the engine look old but I couldn't see any cracks right through.

If this is the prob is there anything I can get to fix it or would it mean replacing the rubbers :-S (parts very hard to get for this bike)

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

tatman · Derestricted Danger Joined: 20 Jul 2004 Karma :

would that run the risk of some glue getting sucked into the engine? I'm kinda hoping the rubbers are the problem because they're a comparatively easy fix... The air/fuel pilot screws are adjusted according to the manual so I din't think that's the problem

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :