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Yamaha wr250f timing


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Hello!

I'am rebuilding top end on my bike and was wondering if timing on cams is right. I almost can't see the dot on exhaust cam but when I look closer it's in perfect level with head. But the and dots arent in level with head, they are higher. 

 

 

Then, is it timed right now or isn't? And the marks on flywheel are good.

Pictures incldued.  :applause:

20141214_160535.jpg

20141214_160602.jpg

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Well, from the top pic, that looks right, but I also need a pic of the crankshaft thru the timing port to see if the timing mark is in proper location with the cams in the same location.  The way I check mine is pull the sparkplug and put a pencil or other long probe into the sparkplug hole to verify TDC.  At TDC, then the cams would be in location in 1st pic on firing stroke.

QU  Did you pull the flywheel and check the teeth on the small sprocket to see if they were sharp and pointed?  Sharp and pointed indicates worn and possibility of jumping time.  Teeth down there should look like the teeth on the cam sprockets.

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Just pull the side cover, use a flywheel puller for the WR and remove the flywheel and inspect visually.  Sharp and pointed teeth indicate wear and crankshaft replacement is needed.  You should replace the cam chain if the test fails.  Drop it on the bench then pick it up by 1 link.  If it kinks and doesn't fall straight, time to replace it.

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  • 2 weeks later...

Ah, well ........

Anything CAN be done I guess, but it would be cheaper to get a whole crank with new rod and bearings.  

I have rebuild Honda XL 250/350 cranks, and Honda XR250 crank.  But I took them to speciality shops for the work.

 

The small sprocket  on the Yamaha is machined out of the flywheel half, so the very least you can do is replace the left flywheel, rod, and rod bearing.  But it still has to be pressed off and on again, and aligned, so unless you do it all yourself, you should buy new.  Hot Rods or others are out there.  Do some research.

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