Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet Iron Barrel => Topic started by: Emmet on January 11, 2008, 12:00:16 pm

Title: Rough Idling
Post by: Emmet on January 11, 2008, 12:00:16 pm
My '06 500 ES has started to idle very rough, frequently missing, lights pulsating, and occasionally stalling with a cough. To keep from stalling, idle's set a bit faster than usual. Adjusting the idle mixture screw (lean or rich) doesn't smooth it out, and the idle speed screw results in very drastic (or sometimes no) changes in idle speed, sometimes very different idle speeds from one stop light to another. It's a bitch to start when cold. Once warmed up, it runs very well at speed, problem's only apparent sitting at idle. The throttle feels smooth and snaps closed with a very audible "clack" (when the bike's not running), changing plugs makes no difference, no apparent air leaks (radiator hose intake manifold with high quality hose clamps), K&N filter mod, choke mechanism seems OK. What am I missing?
Title: Re: Rough Idling
Post by: Leonard on January 11, 2008, 03:34:11 pm
Did this just start all of a sudden or get progressively worse?  Did it start after you made some kind of change like a main jet, timing or adjusted the points?  Do you have a fuel filter?  Just from what you've said I'm thinking some kind of gunk in the idle jet.
Title: Re: Rough Idling
Post by: cyrusb on January 11, 2008, 03:42:19 pm
How many miles? When was the last valve adjustment? Last point adjustment? These things weigh very heavily at idle speeds and starting.
Title: Re: Rough Idling
Post by: Vince on January 11, 2008, 04:44:06 pm
All of the above. It sounds like the carb needs to be cleaned. This means complete disassembly. Taking off the float bowl and hosing it off is not enough. Pull every jet and clean them and the carb body passage ways as well. A tight valve will sometimes cause these symptoms. Also check the intake manifold between the carb and the head. Atear there will cause an air leak with the same symptoms.
Title: Re: Rough Idling
Post by: Spitting Bull on January 11, 2008, 05:15:22 pm
Do you have the PAV system fitted?  If so, check that the vacuum pipe from the right-hand side of the carburetter hasn't come adrift.

Tom
Title: Re: Rough Idling
Post by: Emmet on January 11, 2008, 10:51:54 pm
Quote
Do you have the PAV system fitted?  If so, check that the vacuum pipe from the right-hand side of the carburetter hasn't come adrift.

AHAH!

Read this, and went straight away to check; whoever had done the exhaust conversion had capped the vacuum tube with a little white vinyl cap, which has now gone missing. A fingerful of hi-temp silicone shoved up it's spout, and it's instantly back to one-kick starting and that low-and-slow tick over we all know and love! After dinner I'll cut it off flush and blank it permanently with a stainless self-tapping screw.
Thanks everyone!