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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: Lo on March 08, 2010, 01:51:55 PM

Title: rough idle, esp. when starting warm
Post by: Lo on March 08, 2010, 01:51:55 PM
Hi peoples, my FJ1200 1TX is running rough at idle. It is not extreme, but it sputters a little and the revs at idle vary (sometimes it almost dies). When I turn the idle up, it will go up too much.
When the engine is warm and I switch it off to start it again in say 15 minutes, I really have to do my best to keep it running on the throttle. It will die easily.

Any guesses? Could it be valve clearance (it's been a while since this was done)?

Thanks from Amsterdam  :hi:
Lo
Title: Re: rough idle, esp. when starting warm
Post by: andyb on March 08, 2010, 02:53:41 PM
Carb synch, valve clearances, pilot jets dirty, spark plugs dirty.

Pick the easiest one and work from there.
Title: Re: rough idle, esp. when starting warm
Post by: jack02 on March 08, 2010, 03:35:02 PM
And check meticulously for any air leak twixt carbs and engine,resulting in weak mixture.
Title: Re: rough idle, esp. when starting warm
Post by: Travis398 on March 08, 2010, 06:36:53 PM
also make sure not to touch the throttle when starting it, just full choke, no throttle. it may need a minute or two before warming up.

i just say this cause i have seen a guy try and pump the throttle(before starting it)  to give it more fuel  :rofl:
Title: Re: rough idle, esp. when starting warm
Post by: fj1289 on March 08, 2010, 11:10:08 PM
If the problem is worse warm than cold, it is probably too rich.  Make sure your choke is not holding the starter plungers open a little bit.  Then try leaning the idle screw about a quarter turn. 

Also, please keep us updated on what you try and what your results are - success stories are motivational and educational for all!
Title: Re: rough idle, esp. when starting warm
Post by: Lo on March 09, 2010, 04:05:03 PM
Thanks for the suggestions. First I will replace spark plugs, air filter and oil/oil filter since they have done 7000 kms already...
Might be a while though  :blush:
Title: Re: rough idle, esp. when starting warm
Post by: Travis398 on March 09, 2010, 04:30:12 PM
hurry spring is coming :yes: