83 xj550 no idle please help !!

I got a 83 xj550 it runs ok but have to use the choke to idle ive cleaned the carbs and did the propane test and got no leaks it revs high if I adjust the idle screw and dies out when choke is off if its about 1/4 choke it runs but sounds like a small block with a big cam kinda lumpyany adadvice on what to look at next would be very appreciated

 

When you say the carbs have been cleaned, how did you do it? Sounds like the slow jets may be clogged. Take the carbs off and disassemble them. Soak them overnight in Pinesol and water (a pretty Pinesol heavy mixture). Clean out the jets and passageways with compressed air and carb cleaner spray. Pay particular attention to the slow jets--use a piece of guitar string (High E) to make sure they are clear.

 

Agreed that the Pilot circuits are plugged, and complete disassembly, soaking, cleaning, and picking are needed, but I'd prefer stronger chemicals blasted in under pressure, compressed air, ultra-sonic tank cleaning, and a side-by-side verification afterwards; where you compare one clean carb to another, while spraying thru the passage in question.

Damn that Gasohol !!

 

Plus it's got a lumpy idle, which will make it sound like it's trying to puke the trans in the process.

IF YOU WANT IT TO RUN RIGHT, you MUST do the following, and in order:

Thoroughly clean and properly service the carbs. The procedure is actually covered quite well in both the factory and Clymer books; here's an exploded Mikuni to help you get started: http://xjbikes.com/Forums/viewtopic/t=31061.html DO NOT submerge the carbs in anything unless you plan to fully break the rack and replace the throttle shaft seals. While it might still prove necessary, there's no sense in forcing the issue.

Accurately and precisely wet-set the float levels. http://www.xj4ever.com/setting%20fuel%20levels.pdf The Mikunis are very sensitive to this adjustment.

Bench sync the carbs.

GET YOUR VALVE CLEARANCES IN SPEC. http://xjbikes.com/Forums/viewtopic/t=14827.html and http://xjbikes.com/Forums/viewtopic/t=29209.html Absolutely critical for success.

Return the carbs to the bike for a running vacuum sync, with the YICS blocked.

Fine tune mixtures as needed.

Try to shortcut or do a less than careful job on any of the above and you will be fighting with it until you do it right. Membership in the "I've cleaned my carbs 5 times" SIG is always open, whether you want to join is up to you.