XT 600 - 43F struggling when warm
 

My 1987 XT 600 (43F) has been great for a year then suddenly after about an hour`s cruising the power went and sounds as though the timing is out. Give it a rest for an hour and then it (always) starts 1st time, runs smoothly until your out for 5 to 10 mins and then it happens again. Replaced the CDI on the recommendation of my local bike shop but they`ve also run out of ideas. Frustrated.

Could your petrol cap be blocked causing a vacum in the tank, the petrol could not then flow to the carb?
A cheap and easy repair ( I'm no mechanic but it may be worth considering)
Good Luck

It did occurr to me when it first happened - tried it, good thinking though, thanks.

Did you try a new spark plug? Petcock working ok? Carburetors clean? Is the fuel fresh?

hi there may be the coil is getting hot and freaking out or the genarater is getting hot and doing the same. your local bike shop should have a coil load tester , also they maybe able to test the genarator, you may also have a bit off old dodgy wireing that is geting hot and not passing current also check all the block connecters/ bullet connectors are clean. is the bike misfireing or is the power just fading away. zigzag

See if you can test the coil both cold and warm. I've also heard stories of them failen when getting hot (driving)

Perhaps it coud be carb related, a loose jet or something = too rich. But i really don't know:(

It`s gotta be something like this - so difficult to check things like CDI`s when hot though given that it`s goes like a rocket when left for 20 minutes. I`ve tried petcock (open float chamber drain plug and check flow) I have visually checked the membrane in the 2nd carb - it looks OK but who knows? I`ll just replace it I think just in case. The coil is the next obvious candidate. I must have been through 1800 posts on HUBB and not found one other incident where this happens. Strange. Will keep you all posted - and thanks everybody, it`s really appreciated !