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Ask Kenny O. Your Own Question
Kenny O.
Kenny O., Motorcycle, ATV, Mules, Side by Side's Product Specialist. All Brands
Category: Motorcycle
Satisfied Customers: 953
Experience:  Worked for Kawasaki Motors as a Product Support Specialist (Factory Support) for 24 years
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I've got a 1988 Kawasaki KX60 2 stoke that we've had since

Customer Question

Hi I've got a 1988 Kawasaki KX60 2 stoke that we've had since it was almost new. About 6 years ago we put a new crank, bearings, seals, and piston in it after the crank siezed. After the rebuild it runs great for about 10 minutes once it drops to idle, it bogs and won't come out of idle with the gas. When it's in this boggy idle state, it's possible to put it in first gear and run with the bike to speed up the engine and then it comes back to life and can be ridden. I've cleaned the carb like 6 times to be sure that that is clean. We've also checked the reeds and those are good. I'm wondering if it's the stator, flywheel, or the coil.
Submitted: 8 months ago.
Category: Motorcycle
Customer: replied 8 months ago.
I'm quite certain that the petcock in the fuel tank is clean as I checked it a little while ago and I also took the fuel supply hose off of the carburetor to ensure that the fuel flows freely enough to always supply enough fuel to the carburetor.
Expert:  Kenny O. replied 8 months ago.
Hi my name is ***** ***** am I speaking to ?I have a few questions, what failed on the crankshaft, was it the big end bearing or mains ?Was this unit pressure checked after the rebuild, and or more recently lately ?Do you have access to a multi-meter ?Thanks
Customer: replied 8 months ago.
Hi Kenny my name is Matt. When the crankshaft failed it was the big end bearing. The unit was pressure checked recently and had great compression around 180PSI. I do have a multimeter.
Expert:  Kenny O. replied 8 months ago.
Thanks Matt, when you say recently please define that and what was the result ?Thanks
Customer: replied 8 months ago.
I just compression tested it today with a rental tester from Oreilly and it was reading 120 psi.
Expert:  Kenny O. replied 8 months ago.
Thanks Matt, that compression is OK, what about a leak down test, I' concerned that you are up against an air leak ? Was a leakdown test performed recently ?Kenny
Customer: replied 8 months ago.
I just did a leak down test with a home made tester from home depot. I took off the exhaust and plugged the exhaust hole, left the spark plug in, removed the carb from the boot and put a pressure tester in the carb hole. I pressurized it to 9 psi and it holds for over a minute. That should mean it's not leaking right?
Customer: replied 8 months ago.
I attached a picture so you can see how I tested it
Expert:  Kenny O. replied 8 months ago.
OK, nice job, rule of thumb is pump it up to 6lbs and it needs to hold that for 6 minutes, then if it starts to drop after that then you are OK, if you lost 9lbs in over a minute then you have a pretty good air leak ?
Customer: replied 8 months ago.
I just pumped it up to like 7.6 psi and it's held for 10 minutes now with no signs of leakage
Expert:  Kenny O. replied 8 months ago.
OK that's good, we can run some tests on the stator, so when this thing gets hot then it seems to act up ?So it acts like its loading up according to you description ? after you clean it out and you say it comes back to life, then does it repeat itself ?Also does it appear that water was under the flywheel cover ?
Customer: replied 8 months ago.
It does not appear that water has been under the stator cover and I've attached a picture so you can see as well. So when the bike is cold you started up and it runs great and then either the carb bowl runs low on fuel or something gets hot and if you let it drop down to idle then if you try to bring it above idle with the throttle it bogs. When it's bogging you can put it in gear and run with the bike to speed up the engine and it will come back to life and can be written and as long as the idle doesn't drop to the boggy idle it's fine. Occasionally if you're just sitting on it while it's bogging it will come back to life like normal but it's rare.
Expert:  Kenny O. replied 8 months ago.
Yeah that looks pretty clean, it sound rich almost like a float level is to high, have you tried shutting off the fuel when its starts to act up, so however long it takes without shutting off the fuel then try shutting off the fuel to see if it will clean its self out quicker ??What about a carbon in the pipe, too much, restricted flow ?
Customer: replied 8 months ago.
I tried adjusting the float level so less fuel gets in the bowl. I also tried shutting off the fuel when it's acting up and it doesn't help. It's really weird, when it's running good and idling it will all of a sudden just drop off to the really slow boggy idle. I actually had some success yesterday after adjusting the float level with having it come in and out of the low idle. But then after 15 or 20 minutes it wouldn't come out of the boggy idle. I don't think it's a restricted pipe. Is there an easy way to check that?
Expert:  Kenny O. replied 8 months ago.
I believe that when this unit is getting hot the engine is seeing a power loss, no that can be many different thinks, it could be a ring issue to an electrical issue, not really convinced that its an ignition issue as it doesn't really exhibit any other symptoms that would point to that, I will include a PDF to check the stator resistance, if you would see a big variance in the readings from hot to cold then I might have you check some dynamic checking. A carboned up pipe or silencer might be a cause or aiding to it, I would for testing purposes remove the silencer and see what happens.Download the PDF file and then get back to me.ThanksKennyhttp://spaces.hightail.com/receive/BNx1M