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yamaha xj 550 won't idle.
Posted: Sun Jun 06, 2010 7:48 am
by manveru
My dads 1981 xj 550 won't idle, and i can't really find anything on the carbs that will adjust all of them at once. Also it is super cold blooded, i'm guessing it needs a valve adjustment, anyone else have any ideas? thanks
Re: yamaha xj 550 won't idle.
Posted: Sun Jun 06, 2010 10:05 am
by haunter
bad idle and cold blooded IS usually the valves being loose
you change the plugs? reseat the wires?
Re: yamaha xj 550 won't idle.
Posted: Sun Jun 06, 2010 10:10 am
by manveru
plugs are new and wires are good. We also seafoamed it, and still no idle. I guess one of these days when i get time i'll pull the cover off.
Re: yamaha xj 550 won't idle.
Posted: Sun Jun 06, 2010 10:24 am
by yamaha_george
haunter wrote:bad idle and cold blooded IS usually the valves being loose
you change the plugs? reseat the wires?
The XJ's i serviced 750/1100/1200 were all cold blooded but I thought that was because of our climate (tropical)
H is right i would check my valves as 81 is along time ago do you have its service history of any sort?
The XJ carbs themselves were sluggish to respond and we blocked 25% of the vacuum intake port over the gas /air main bore to make them a bit "snappier"
Re: yamaha xj 550 won't idle.
Posted: Sun Jun 06, 2010 10:34 am
by manveru
nope i don't have the service history, the guy we bought it from supposedly adjusted the valves and that was back in 2006, i don't think he did a good job if he did because i thought i could hear some ticking from them. They are definitely making noise now, and the motorcycle has always been cold blooded. Last year it would idle, broke it out of storage, changed the oil and plugs and now it won't idle.
Re: yamaha xj 550 won't idle.
Posted: Mon Jul 12, 2010 11:16 am
by Fartblood
The 550 has YICS, and as the carbs age the idle can get uneven and the power delivery lumpy.
Nice machines BTW. A friend of mine owns chassis number 000004, believed to be the oldest surviving XJ550 in the world. Wouldn't mind one myself.
Re: yamaha xj 550 won't idle.
Posted: Sun Aug 14, 2011 6:11 pm
by Traeldor
erased from edit. I need to read responses before responding
Re: yamaha xj 550 won't idle.
Posted: Sun Jun 10, 2012 6:19 pm
by wicky383
Check valve clearances first, if those are good I would suggest taking the carbs apart and cleaning them. Just tore my friends xj carb's apart and cleaned them (dirty as all hell) and now it fires right up, used to be a pain to start. However after you've put them back together you'll need to first check the fuel level in each of the carbs float bowls which requires a special tool, and then sync them which requires a sync gauge.
I'm not a professional bike mechanic but I am a ASE certified auto tech, I work on my own bikes and friends bikes so basically I with a service manual I'm good to go. My advice is if you're not feeling up to it just bite the bullet and take it to a shop and get it done right.