Question about 1988 Yamaha XJ 600

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Hi i brought this bike in the summer and its never run right,its fine on tick over but when the revs get up it starts jumping like its lacking fuel, ive cleaned all the jets but it didnt help, it has k and n air filters fitted and ive been trying to find a stanard air box to see if this sorts the problem but i cant find one for sale anywhere, i was wondering if you could please tell me the standard main jet size for this bike, and also what size jet should be in for the k and n fitted, currently it has 107.5 jets fitted but im not sure whether these are the stanard size or have been changed, many thanks scott

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Hi... if you have vacuum cabs... Have you checked to see if the vacuum on the fuel tap is working correctly.. Take the fuel pipe of the carbs, put the fuel tap to on.. If its a vacuum tap there should be no fuel coming out. Put the pipe in your mouth and suck on the pipe, if fuel comes out then stops it seems to be working. Also check the diaphragms in the top of the carbs are not split or have any pin holes in them. You can do this but holding the diaphragm up to the light.. (If they are vacuum carbs).. You can aso check to see if the carb rubbers are leaking between the carbs and the engine.. You can do this by starting the bike up and leave it ticking over. Get some carb cleaner or WD40 and spray it onto the rubbers between the carbs and engine. If the engine pics up speed (revs go higher) then the rubbers need to be changed.. Hope this helps you out...

Good luck.. Tony.

Posted on Nov 18, 2013


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should run then we had a fzr 600r and did work to it so i know from experience..

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SOURCE: aerox

Needle fallen into the needle jet? Blocked exhaust?
Please get back to me if you require further asssistance.

Posted on May 27, 2010

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