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2009 yz250f HELP!

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Tore bike down to check valve clearances, bike runs great. When I check with a feelers gauge I can't fit the .10mm gauge in, the biggest I can get is the .04mm and I can't seem to get my timing marks "I" and the marks on the cam sprocket to line up correctly am I doing something wrong pls help. Timing mark on flywheel "I" set at TDC and piston is all the way up. Any help would be appreciated.

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If the Piston is at TDC with the timing marks in the flywheel then the cam sprockets should look something like this. If not you may need to adjust them accordingly and make sure to re shim. You can get the actual clearances and timing marks from your yz service manual as they may be different. These images are from a wr450fs. I am by no means a professional but I Hope this helps.

IMG_20170517_172855744.jpg

Screenshot_20170519-115121.png

IMG_20170517_172845634.jpg

Edited by FatCowKiller

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My issue is that the bike runs great, trying to check valve lash and I'm setting it at TDC off the flywheel timing marks and the marks on my cam sprockets don't line up with the head like they should...but it runs great so I think I must be doing something wrong gonna give it hell again when I get outta work tonight but thanks for the info I appreciate it

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two things-

 

first this needs to be moved to the YZ forum, not the XR250/400 forum. 

 

Secondly, what timing mark on the flywheel are you referencing? there are TWO marks. make sure you are in fact at the correct timing mark, then verify cam marks. there are 4 dots, two of which are on the OUTER side of the cam gear, and two that are at 1130/1230 like shown in the pic on the prev posts. 

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I'm new to the forum so my apologies but I did start a thread in the wr/yz forum and got some good info. There is an "i" line on the flywheel which indicates TDC and when that is lined up my cam sprockets are at about 10 and 4 o'clock

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Just because it's running great doesn't mean it's healthy for the bike, if your clearance gets too low the valves can begin to melt. Mine ran great for like an hour of use before I started to have major problems due to the valves not having enough clearance. Better to shim it properly now for a few bucks than spending hundreds on a rebuild because your engine melted.

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