Hi There , i seem to having problems with my KLR 650 , when i get out on the open road and after riding for about half an hour or so the bike starts to miss fire and surges , feels like a fuel problem but when fuel is checked all is ok , i had this problem once before on a long ride and found my headlight wasn't working so when i replaced the fuse ( i guess the same fuse controls the CDI unit ) all was ok , now yet again this problem has manifest but the fuse is ok , on one long ride i kept stopping then would drain the carb and this seemed to help but i suspect the cooling down was helping when i stopped more than my tinkering , what do you think could be the problem ?

Is your problem related to the weather? I've recently had a similar issue on my 2007 KLR (about 50k miles). In my case, stopping (with or without shutting off the engine, like for a traffic light or two) cures the stumble/misfire temporarily. The longer I stop, the longer the cure, but it starts up again after 2-25 miles. It isn't affected by venting the tank---stopping for just long enough to open the cap doesn't work, but stopping for 5 minutes to cuss and moan without taking any sort of constructive action does.

For better or worse, this was happening in hot weather last week--95 F/35 C with high humidity. Now that it's cooled off, I can't get the problem to happen at all, even under load up steep grades. So I'm taking off into Mexico, fully expecting to be incapacitated next time I hit serious heat. The alternative is to hang around forever, talking to mechanics and posing questions on internet forums.

The main suggestions aside from the obvious checking of jets, spark, petcock and the like, have involved vapor lock or heat-related electronics. I don't have a spare coil, or I'd try it out. I am now carrying some foil insulating tape and will start plastering it all over fuel lines and anything else that looks vulnerable to heat-induced malfunction if and when my problem recurs.

I did also use some sort of mystery miracle stuff in my last tank of gas on the recommendation of a dealership mechanic. He suspected carbon buildup in the top end and said this stuff would deal with it. I suspect over-eagerness to get me out the door and on to the next mechanic....but what do I know? Another guy said all his similar problems vanished when he finally found the tiny holes in his carb diaphragm on the third inspection...but I think I'm done taking my carburator apart for a little while, at least.

Hope that's helpful. Please post here if you do diagnose a lasting solution.

Mark

Misfiring and dying while it is hot weather and when engine warms up after some running time ; NO problem when weather is cold.

Sounds like it may be CDI related . Had a simillar problem once with a Suzuki GS 550 which would suddenly stutter and die after running warm, then after cooling off 10-15minutes would start back up.Sold it. Just recently my GS 1100 came down with it after 250 000 km , -- several times just dropped dead at a stoplight after summer in-city riding where cooling was not optimum. After a half hour it would refire again, not a good thing to have on a tour.
In the BMW case it was found to be the small ignition pickup magnet set which signals the CDI unit.Problem was solved by installation of a new pick-up unit.
The KLR may now be having similar problem- misfire when hot, good when cooled down ,until hot again. Just a suggestion.

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http://advrider.com/index.php?thread....207964/page-5 then scroll down to post #93

do you have an inline fuel filter?
this will cause your symptoms,whether its vapor lock,or lack of a good flow of fuel because of the filter,i dont know.
this problem is well documented elsewhere.the bike already has filters in the tank,no need for aftermarket additional filter.

I can't speak for the OP, but I added an inline filter only after this problem began, now 2000 miles ago. I'm aware of the theory that says you don't need one, but hey, it's easily accomplished and easily discarded if it proves a problem.

The possibillity of a heat-sensitive CDI gives me bad dreams. No way to test it, since the issue arises only under way in brutally hot weather. No apparent way to get it warrantied. In fact, no obvious way to get ahold of one now that I'm headed south.

Part of what I find most puzzling is that the misfire doesn't only go away due to the engine cooling off. It also goes away when I stop to wait for a traffic light, which sends the engine temperature even higher. I find this aspect inexplicable....but that's not unusual.

Thanks (from me) for responses. Hope the OP chimes back in.

Mark

Had an in-line filter , on the first time i had this problem soaked a cloth and wrapped it around the in-line filter , this seemed to work for a while , again maybe it is just the stopping to do this that was helping , decided to remove the in-line filter altogether , the problem still continues , my instinct keeps looking at the cdi unit , is this a common problem on the KLR ?