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trying to get my motor running better

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trying to get my motor to run better.

working on the TOP END


Kawasaki klx250 valve specs

exhaust: 0.15-0.24 mm

intake: 0.10-0.20 mm



First Time:

   took it apart to check the valves. (without removing tensioner)

   put it back together changed the oil


  it was making a tapping sound (prob the chain ) shifting bad




Second Time:

  took it apart again, reset the timing, reset the tensioner and sub tensioner

  checked the valve clearance

  -exhaust: 0.14 and 0.15 mm

  -intake: 0.13 and 0.10 mm


   after the second time runs a lot better , shifts smooth as hell and no more chain noise

  **but slight tapping noise and a lot more backfire , this  is what I'm worried about**

   I want to get the exhaust to around 0.21mm (I think the tapping is the valves)

   slight hesitation , I think its the carb or exhaust









Edited by horrorfan

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5 hours ago, brewster said:

We need more info.  Any mods to the air box or exhaust?  Carb jetting.....is its stock?

Ride on



its all stock. carb is stock , the air screw is plugged so its the stock setting.

air box is stock... no leaks or oil in the air box

motor is all stock ..mileage ~24,440 

no motor leaks , no carb leaks

lightly dropped a few times

no electrical issues, the guy installed a USB port thing and a really annoying headlight and taillight mod ...tail like flashes three times when pedals are pressed , head light has a constant blinking mod which I have to deactivate upon turning on the bike everytime

swapped the motor oil twice recently , swapped it once last week  ...rode it for a while then swapped again.. oil is all clear.

inspected the cam lobes and cams ..looked fine. 


a lot of backfire after I put the motor back together ....but honestly feels like it drives a lot smoother , shifts smoother.

Im 100% sure I set the cam timing correctly It basically perfectly matched the picture manual .. 

I reset the tension fine ... released tension , installed the cam , put the chain on bolted the cam down then put the tensioner and sub tensioner back in...

for the tensioner I compressed the arm all the way down that bolted the spring in...




another thing weird is tiny bit of oil coming from one of the tank fuel hoses ( I think its one of the overflow drain hoses....whatever its called)

this is REALLY strange because I unplugged the hose and there was NO oil at the top of the hose but a bunch from the bottom .... ?!?!?!!!!! 


Edited by horrorfan

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Gearbox oil condition does affect this bike, as oil quality fades so does shifting action. Keep the oil and filter clean for best results. 

The one intake is tight and one exhaust is to tight and needs to be taken care of before you burn a exhaust valve. 

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