2013 KX250f-Only starts top dead centre

mingham97
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mingham97
Edited Date/Time 11/16/2015 1:21am
I just have a few questions that you could help me address..
1.) It only starts from top dead centre
2.) It doesn't idle properly

It's got a pro circuit system on it but I doubt that's contributing to anything...
Any suggestions would be good!
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colintrax
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colintrax 11/12/2015 4:19pm
11/12/2015 4:19pm Edited Date/Time 11/12/2015 4:20pm
Double post
colintrax
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colintrax 11/12/2015 4:19pm
11/12/2015 4:19pm Edited Date/Time 11/12/2015 4:19pm
I had a pro circuit system on my old KX250F. Idled like crap, and wasn't the easiest to start. Went back to stock and the idle was great. Certainly lost some top end with the stock exhaust. But IMO the pro circuit pipe was too large for anything but a full blown race bike with the idle screw turned up
Go back to the stock pipe and see if that fixes your problem
731chopper
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731chopper 11/12/2015 5:42pm
11/12/2015 5:42pm
I have a full pc exhaust on my '14 kx250f and it both starts and idles perfectly. The motor is stock so I don't think that is your problem unless there is something in there restricting the flow. Did you buy the exhaust new or used? It's a long shot but maybe check to see if something is stuck down in there.

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Paw Paw 271
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Paw Paw 271 11/13/2015 6:34pm
11/13/2015 6:34pm
Have you checked your cam chain and valve timing? It does not take much cam chain wear to cause this issue.

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mingham97
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mingham97 11/13/2015 9:09pm
11/13/2015 9:09pm Edited Date/Time 11/13/2015 9:11pm
I brought it and the valves were replaced (had the old ones given to me too). I'm going to play with the couplers when she's back together. Would the Cam chain and valve timing contribute to idling problem, starting problem or both?

I've hassled the guy I brought it off about everything he's done because it hasn't been quite right since the day I got it. When doing quick shifts (throttle wide and use the clutch to change), I'll drop the clutch and it just revs out for a split second when it's supposed to be engaged
Paw Paw 271
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Paw Paw 271 11/14/2015 10:56am
11/14/2015 10:56am Edited Date/Time 11/14/2015 10:57am
Yes a worn cam chain will change the valve timing and have a big effect on starting and running. Ask the old owner if he replaced the cam chain. The service manual gives good details on how to check it. For me, I would just replace it to be sure.
The use of an incorrect oil will cause this issue with the clutch as will worn fibers.
Also if the valve seats were not cut when the new valves were installed it will cause running and starting issues.
Have you checked the valve clearances and the cam timing?

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braaap401
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braaap401 11/16/2015 1:21am
11/16/2015 1:21am
just because the valves were removed & replaced does not exclude them from regular valve adjustments every 10-15hrs of riding. this is why your bike will not start from the compression stroke. just an FYI, you should ONLY kick a bike from top dead center to begin with, otherwise you can cause valve train damage. as for the choppy idle, the bike needs a tune to compensate for the Pro Circuit. and for the mis-shifts and false nuetrals, thats the clucth plates/fibers and possibly the clutch basket depending on how many hours the bike has on it. as of right now i can 100% tell you need a valve adjustment, new mapping, and clutch plates & fibers. minimum. unless you enjoy false nuetrals at 50+mph. just went through the same with my 07 kx250f & 01 rm125 doing the same thing with spanked clutch

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