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cam chain quenstion

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2010 kx250f stock cams

how man pins in the cam chain from the top punch mark on the exhaust cam gear to the top punch mark on the intake cam gear when at TDC?

thanks all trying to get this bad boy running

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Not the best pic but if you count pin 1 at the exhaust cam dot where it is right at the cylinder head upper surface, then the upper dot is pin 9 and the upper intake dot is 20; the intake dot at the head surface is 28. This is with your marks aligned at the stator/rotor cover holes, and the piston of course at TDC (all the way at the top, compression stroke, just before firing the spark).

camchainKX250F-1.jpg

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Here is a better pic, I always just count the 12 pins between the two inner punch marks.

kxfcamtiming.jpg

Edited by D-K

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thanks so i put my top end in and before i did all this took measurements and all valves were in spec now the intake valves are out of spec can figure out why but goin to try to see what i can do today

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Here is a better pic, I always just count the 12 pins between the two inner punch marks.

kxfcamtiming.jpg

i cant seem to get the punch mars even with the top of the head if i jump one tooth it to bigh of a change should i get it as close as possible?

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i cant seem to get the punch mars even with the top of the head if i jump one tooth it to bigh of a change should i get it as close as possible?

Yes, as the timing chain stretches the dot´s will be slightly off. But if moving it a whole tooth would make it even worse, go back.

Start with the front (exhaust) cam and keep the chain taught, then put in the rear cam, counting 12 pins, then put in tensioner body, then spring, rod and cap.

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when you checked your valves, was it before you put new cams in (I thought you had done that recently unless I am thinking of someone else)? Your valves could be slightly off if you put new cams in even if they were good before. If the old cams are worn and new cams are +/- a couple of thousandths from stock specs that could put you off a bit. Always check with the new cams even if the valves were within spec with your previous cams. Otherwise, you may have some carbon buildup on the valve seating surfaces that is causing some fluctuating measurements, but in that case you are probably due for cutting your valve seats and new valves. Just check carefully and try to use a set of gauges that taper at the end and are long enough to bend into a gentle curve and not have lots of friction just because of the crazy angle. I know it is a tight fit into 3 of the 4 valve buckets.

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DK - thanks for the info she is running now and all in spec

DRZADAM- thanks but the cam were the OE cam just re installed after a new piston!! and yes i have a set of some sweet feller gages fater works for a precision gage company...alot of work with Harley and Timkin most bearings in OE bottom ends!!

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