KE250 running away - Kawasaki Motorcycle Forums
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post #1 of 6 (permalink) Old 10-30-2016, 06:31 PM Thread Starter
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KE250 running away

Hey all,
My brother just got an old KE250, sort of a barn find, cleaned out the carb and he has gotten it running but it runs away every time he starts it, goes up to like 9k rpm and stays unless you pull the spark plug wire.

Anybody got any idea what could be causing this to happen and how to fix it? We think it's got something to do with the carb but....
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post #2 of 6 (permalink) Old 10-31-2016, 03:05 PM Thread Starter
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Just to give a little more background it used to be in Montana and he brought it over the the Oregon coast, so it underwent a big elevation change, thus my thinking for it maybe needing to be rejetted? I've never heard of a 2 stroke running away just from lean jetting though...
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post #3 of 6 (permalink) Old 11-01-2016, 03:43 PM
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It is from a lean condition. Now the reason for the lean jetting could be a few things. Its an old bike so the crank seals are probably hard or not sealing properly. Also someone could have messed with the jetting as well, the carb may not be set correctly or as clean as you think you go it. The elevation change will have an effect as well.

The fix is to start from scratch and make sure everything is in order before diagnosing further. This means putting the carburetor settings back to what ever the manual calls for and then checking for vacuum leaks (the common ones are the crank seals).

I have videos and things on my website that can help.
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post #4 of 6 (permalink) Old 11-07-2016, 11:34 AM Thread Starter
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Originally Posted by thejunkman View Post
It is from a lean condition. Now the reason for the lean jetting could be a few things. Its an old bike so the crank seals are probably hard or not sealing properly. Also someone could have messed with the jetting as well, the carb may not be set correctly or as clean as you think you go it. The elevation change will have an effect as well.

The fix is to start from scratch and make sure everything is in order before diagnosing further. This means putting the carburetor settings back to what ever the manual calls for and then checking for vacuum leaks (the common ones are the crank seals).

I have videos and things on my website that can help.
Thanks for the help, we have ordered all new gaskets and crank seals for it, so I guess that's our next step. Any idea where I can find a downloadable manual for this bike? I've tried looking but can seem to find anything.
Also, the carb was pretty nasty and some of it was corroded from age, now it's clean but has pitting and such in some paces from the corrosion. Do you think it will need a new carb?
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post #5 of 6 (permalink) Old 11-07-2016, 12:11 PM
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Thanks for the help, we have ordered all new gaskets and crank seals for it, so I guess that's our next step.

Any idea where I can find a downloadable manual for this bike? I've tried looking but can seem to find anything.

Just buy a paper one from ebay, like this one Kawasaki Ke250 Service Manual They are cheap and you will use it for more than just this issue.

Also, the carb was pretty nasty and some of it was corroded from age, now it's clean but

has pitting and such in some paces from the corrosion. Do you think it will need a new carb?

Maybe, if the pitting is bad enough (in the carb body) in the small passages it is possible fuel and air will not flow properly or at the correct rate for proper jetting. Also that corrosion could be partially blocking a passage or two, and thus the lean condition you have.
My responses are TO THE BOLD TYPE FACE QUESTIONS.

You won't like the price of a "good" used carburetor but you will have to pay for that if you want it to tune and run correctly. I also strongly discourage trying to find a same sized carburetor off another bike OR one of the new knock off carburetors, while these can be options, they are not good options for novice tuners and sometimes drivability compromises have to be made as replacement (different) carburetors may not flow and meter fuel correctly for the KE250 engine. Basically most people tear their hair out trying to make different carburetors work with their engines, especially if they are not experienced with jetting and tuning.

I do see there is one complete carburetor and a carburetor body (no guts) on ebay right now. They may be in better condition than yours.

Last edited by thejunkman; 11-07-2016 at 12:18 PM.
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post #6 of 6 (permalink) Old 03-03-2017, 06:55 PM
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I would strongly recommend checking the carb intake boot between the carb and the jug . the tiniest crack in that boot will give you the symptoms that you describe. a good test for that is to spray some carb cleaner or wd 40 around that boot and listen for rpm changes or the engine coughing from burning whatever solvent you've chosen. if you use an oil based spray such as wd 40 the rpms will drop. which will probably be better for ur case being the bike is revving so high. no need for it to rev higher. a good safe one to use is fogging oil . it's safe for a running engine to ingest it as that is what it is designed for. any rpm change means make sure the clamps are tight and I'd they are replace that boot
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