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Outlaw45

New to me '05 YZ450 valves

31 posts in this topic

I picked up a '05 YZ450F last fall and this is my first dirt bike.  Today I tried to check valve clearances for the first time.  Removed head cover and turned flywheel until indicator mark lined up on flywheel.  When it lines up the indicator on the cams do not.  I'm not a mechanic at all and I'm a little afraid on what to do next.  I don't know if the previous owner had it setup this way or not.  The bike seems to run fine.  Should I remove the cams and adjust them so the indicators line up so the intake lobes are pointing to the rear and the exhaust lobes point forward?  Then check valve clearances?

 

Maybe I'm over my head

 

Rob

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The "H" on the flywheel is for ignition timing, the "I" next to the H is the TDC mark. Line up the "I" mark and then take a picture of the cams and upload them on here so i can take a look.

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I checked clearances with the cam lobes flat as possible(intake pointing to rear, exhaust pointing forward).  They wouldn't line up.  Checked again with the flywheel indicator lined up.  Valve clearances measured the same. 

 

With the cams in this position the indicator points on the sprocket don't line up with the case head.

IMAG0552_zps02e00045.jpg
IMAG0560_zps92714d1d.jpg
IMAG0559_zpsa8b9e9ad.jpg

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Thats how you want them when you check them. And if you say it runs good its probably ok. If sprockets were off a tooth or two it wouldn't run well if at all

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ImageUploadedByThumper Talk1396505697.089097.jpg

If you zoom in the dots will line up with the top of the head when properly at TDC. I have an 05 also and just did a top end, and went through all of this. Make sure that the marks are right for TDC. It looks like (H I ) the H is for a timing light and the I is for you. You can also use a straw or long screwdriver down the spark plug hole to double check when the piston is topped out.

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+1 on checking TDC with a probe. On my tuned 04 with trick side cover without an inspection hole it's easier than dropping the cover off.

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Just curious why you have the tensioner retracted. Did you pull the cams and put them back in? Or does it call for that on an 05? The manual for my 06 says nothing of retracting the tensioner to check the valves.

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I checked clearances with the cam lobes flat as possible(intake pointing to rear, exhaust pointing forward). They wouldn't line up. Checked again with the flywheel indicator lined up. Valve clearances measured the same.

With the cams in this position the indicator points on the sprocket don't line up with the case head.

IMAG0552_zps02e00045.jpg

IMAG0560_zps92714d1d.jpg

IMAG0559_zpsa8b9e9ad.jpg

You are going by the wrong mark on your flywheel. It is the line over top of where that dot is on your top picture there. ImageUploadedByThumper Talk1396533986.446098.jpg

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Pull your spark plug and locate Top Dead Center with a probe.  Then look at which mark you're lined up with on the crank.  You're rotated way too far forward.

 

DON'T rotate the engine past any point where a cam lobe starts to bear against its lifter unless the tensioner is in place.  The chain will skip if you do.

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Just curious why you have the tensioner retracted. Did you pull the cams and put them back in? Or does it call for that on an 05? The manual for my 06 says nothing of retracting the tensioner to check the valves.

I took the pic after I checked valve and started to remove the cams.

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I've followed the manual (although maybe wasn't at TDC) to change out the shims and have done that.  Now I'm bolting down the cams and will check clearances again.  

 

When I removed the tensioner the manual said to. 

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DON'T rotate the engine past any point where a cam lobe starts to bear against its lifter unless the tensioner is in place.  The chain will skip if you do.

Are you talking about turning the flywheel while the tensioner removed? If so, no I haven't done that.

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Yes thats what grey is talking about. I saw slack in the cam chain in your other post. Didnt know you had the cams out already. Proceed. :)

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Not if you do it the right way.  Start by making sure the engine is at TDC, then look how the marks appear in the window.  They'll be seen at the top. 

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