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Yz426 cam timing question

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Ok I have to shim my valves and I put theengine at tdc per the mark on the flywheel

 

The cams dont line up with the cylinder head could they have jumped timing?

It looks like they are off the same amount tho and in the same direction

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On 6/8/2017 at 6:31 AM, deweym21 said:

Are you sure you had it on the compression stroke?

Without the cams, there is no compression stroke.  One TDC is the same as another.

The engine is very easily moved as much as 5-6 degrees or more in either direction from TDC because the piston barely moves, and causes very little drag on the crank because of that.  You can end up a tooth off just by tugging on the cam chain.  Retime the cams.  It looks like the exhaust cam is retarded one tooth farther than the intake to me.

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Without the cams, there is no compression stroke.  One TDC is the same as another.
The engine is very easily moved as much as 5-6 degrees or more in either direction from TDC because the piston barely moves, and causes very little drag on the crank because of that.  You can end up a tooth off just by tugging on the cam chain.  Retime the cams.  It looks like the exhaust cam is retarded one tooth farther than the intake to me.

Thank you for the correction good sir

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The error you're thinking of applies to timing the ignition when the ignition triggering system is driven off of the camshaft.  There, it's possible to be on the wrong TDC, one full turn of the crank away from where you belong.  Most singles these days trigger the ignition off the crank, though, so it fires on every TDC.  It's the cams that give the compression stroke and the exhaust stroke their two different characters.

 

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Thanks for the input,  I'll try re setting the exhaust when I re assemble

 

Another question I had is the center intake was zero on clearance so I don't know how much smaller to go on the shim, do I need to torque the cam to spec each time I reinstall it to check clearance or can I get away with just snugging it down

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Just snugging is adequate for getting into the right range, but always double check after torquing.

The bad news is that your center intake needs to be replaced.  The spec is .10-.15mm, and a fundamental rule of thumb is that when a valve needs to be shimmed two or more shim sizes (.10mm) smaller than it had when it was last built and correct, which yours obviously does, the valve needs to be replaced.

To select a size for a valve at zero, assume you need either .10-.15 smaller than what you have now.

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Hey guys I know there has been a lot of conversation on the 450 to 426 cam swap. I accidentally bought a yfz450 cam and he doesn't accept returns. Will this cam work?

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depends what year yfz cam, 04-07 yfz cam should be the same as 03-05 yz 450 cam, because I'm in the process of using a set of stage 2 hot cams for a yfz I got given to me .

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