86 xr 600 problems

hey guys im newb here and i need help sorting my carbs on my xr 600 when i'm riding the bike any thing over 1/4 throttle it boggs down and backfires and then loses power until i back off it is a loud backfire not just a pop starting was fine when i got it, 5 kicks max the jets are stock 122,122 and 48 now it is hard to start i also have jets form a xr500 which are 135,108, any help would be great as i dont have a manual and it is making life difficult also i live at 600m above sea level so what should i jet it for as can't wait to get back on the trails

Edited by barnznall

hmmm,,Yep. I wouldn't be so fast to blame the carbs. Those symptons are also those of a faulty ignition coil,,borrow one to suit from preferably another XR and test it in your bike. It could be a number of things causing your issue,,a short, the stator, the carbs,the coil,the cdi,,,and on it goes. The 122's are about right for stock,,600ms is neither here nor there.,,those 500 jets are a bit odd.Think you'll find they are a 105 and a 108,,,to lean for a 600. Check the basics first with the carbs..ie,,is the gas tank cap breathing correctly,,does it have an inline filter??..is it clear and allowing good gas flow to the carbs..

yeah i have replaced the coil no change it has good spark the stator had been replaced before i bought the bike so the only other things the wiring has been chopped No lights etc just the starting circuit basically apart from that it leaves the cdi or the carbies. it only has the tank filter on it so i bought a inline filter to put on it. A friend has lent me a set good condition carbies off a stock 86 xr 600 to try as well so this arvo i will try them with the inline filter and see how it goes and if that doesn't fix it. it has to be the cdi does any one have a manual in pdf that they could email me:worthy: as that would be a great help as im working blind at the moment.:smirk:

okay, I had a very similar problem on my now running 84 xr 500. I tried everything, changed every electrical component, checked exhaust, carbs/jetting, filer, valve adjustment, took the valve caps off inspected the cams, etc.

Finally I took the motor out of the frame to get a good look at the valves, I found the cam chain adjuster had been put in wrong and had worn it down to basically nothing. (the adjuster was riding on the back of the chain not on the slider assembly) I instaled a new on and checked the valve timing and it had jumped two teeth. corrected that and voila... runs great. you may be able to do in in frame I could not.

good luck!

Which parts of the manual do you want. I have one for the single carb models in PDF but it'd be too large to send as one via email..It's in sections of about 3.5mb or smaller,,Can throw it your way if you want. You don't really need a manual to do the carb swap anyway. Remove the sidecovers the seat and the tank. Undo the clamps on the inlet manifold and the Air intakes..Remove the clamps..Pull the airbox tubes back behind the frame downtubes that are about 6 inches back from them..one tube behind each frame downtube..Disconnect the choke ,,Remove the carbs to the right..little bit of manipulation will have them out..Undo the accelerator cables,,attach to the other carbs and put them back on the bike using the same method..

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