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Discussion Starter #1
I know - unoriginal forum introduction. Bought bike on the cheap from a frustrated dude. He thought gas was pouring out of carb overflow. Really was the crankcase vent. I rebuilt petcock (fuel leaked into intake through vacuum line) and had an awesome low mileage 2005. Flushed oil well and figured bearings, lifters and seals survived the gas bath. Last time I rode, bike stopped running and I killed battery trying to start it. Pushed it home - it sucked. Fuel cap vent clogged and starved carb. Bike sat. Would start, but unhappy. It sat. With a charged battery, I tried to renew efforts. No start and horrible back fires. Bought carb rebuild kit. No start and horrible back fires. Bike on jack, and I see fuel leaking out of the air breather box drain tube! The orientation of front end had fuel going back instead of into cylinder. Bought a cheap petcock (do Kawasaki petcocks routinely fail?). Gas in bowl. Battery fresh off charger. Spins fast. Back fires horribly. My compression tester didn't have the 12mm plug size, but my thumb jumped off the hole. I sprayed some starting juice in the airbox for some type of satisfaction and with throttle open flames came out of the side of the airbox. Good times. I'm thinking it jumped time, but how? I set everything TDC after removing valve cover. All marked lines are good and chain is tight. Valve clearances are on the tight side, but within range. Bike only has 4700 miles. I bought a new plug off eBay. Probably buying an adapter for compression tester today. Option #1 - button it back up and repeat failures. Option #2 - keep peeling it apart and do a leak test on the valve seats. So how are y'all doing?
 

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Sounds like a FOULED spark plug from afar, have you not installed the new plug yet?

Long term storage with deteriorating gasoline causes most all of the fuel tap & carburetor problems. A flooding carburetor fouls spark plugs. Old gasoline fouls spark plugs.
 

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Discussion Starter #3
New plug coming in mail. Old plug clean and happy looking. It makes a spark, though hard to tell how lively without my friend holding on to it. Fresh fuel. Battery isn't new, but hot off the bench charger and turns it over swift enough. Carbs don't frighten me, so I'll probably look into it one more time. I ordered the 12mm adapter for my compression guage. Not feeling the groove yet for pulling camshafts and doing a leak test of the valves (may be overreacting). Did have a dream about mud daubers in the tailpipe, so I may disconnect and blow air through it! New petcock was cheap and I will probably get a kit for the old one. I have a lot of machines here and fuel is always a concern. Thanks for patting me on the head. I'm used to blasting starter fluid into carb throats and having an engine run for a moment, but not spit flame back at me!
 

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No Need to remove cams or even cam cover to perform a Leak-Down Test.
If the 1st TDC mark allows massive leakage, turn the crank one more revolution to TDC Compression stroke. All valves should now be closed.
10% leakage is very common.
 

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Discussion Starter #5
I have the engine clocked at TDC with all the lobes facing away. Exhaust valve clearances are a tight .006 and the intakes are at .004. That tells me they are all closing. I don't think it tells me much about their seat conditions. I also wondered about the engine decompression system when starting and maybe whatever tells the computer to do it's timing! Some sort of camshaft position sensor, but I'm still trying to learn about this thing! Thanks for keeping my thread hot! - Scott
 

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The closer to MAX Spec (but not beyond) all of the valve tappets are, the better. I would rather have a snug .008" on the exhaust tappets than a sloppy fitting .010". Because with a sloppy .010" the owners hear too much valve tick and it makes them worry. But having a sloppy .009" or even better a snug .010" on the RH exhaust valve with the KACR will yield the best compression because the KACR releases the tappet sooner during the compression stroke, trapping more compression.

There Ain't No Stinking computer or camshaft position sensor on a stock KLR. But I do know of one that does, https://www.klrchris.com/
 

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Discussion Starter #7
I've buttoned up the cam cover. No apparent bizarritudes. Recorded valve clearances. Dropped the 10mm top-inside bolt to the cooling fan into the skid plate about four times. I'm waiting for my new plug and compression tester adapter. I'll take carb back off and go through it one more time for kicks. Past threads indicate creepy experiences with the clutch & kickstand safety switches, so I'll consider overriding them (I guess that is well blabbed about somewhere here). And yes, I had the kill switch in the run position... Thanks - Scott
 

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Sounds more like carb issues to me. BTW, in order to flood the cylinder, you have to have a petcock failure (or a manual one left on) AND a bad float valve. It sounds like you repaired/replaced the petcock but I'm not sure you adequately addressed the carb.

I love having 2 KLR's......I would just swap carbs and see.

Good luck,
Dave
 

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Discussion Starter #9
I can't believe there aren't any more accounts of a petcock leaking through the vacuum diaphragm, down the vacuum line and into the intake manifold. Like you, I figured that there would need to be both a petcock and a float valve failure. I'm destined to be a manual valve kinda guy! I even have a "fuel off?" sticker in my fairing! I'll take the carb back off Monday - gotta bug out for weekend - Scott
 

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I also use a manual (Raptor) petcock on mine......I have no problem remembering to turn them off as it's just like the 30 dirt bikes I've owned.

Dave
 

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If one actually looks at the oem petcock diaphragm assembly, there is an external air vent passage in the 'fuel side' of the gray plastic divider. This open air passage allows the 2 diaphragms to flex properly.
This external air passage should also allow any fuel leakage from a Failed inner diaphragm to leak out of the assembly and bring cause for replacement long before allowing degradation of the outer vacuum diaphragm and dribbling/sucking raw fuel down the vacuum hose & into the combustion chamber.
 
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