finding tdc with a Moose flywheel weight

I was adjusting the values on my YZ400. Before I took that cams out to get two shims I marked the chain and cam sprockets. The marks got rubbed out and now I can't find TDC because the previous owner installed a moose flywheel weight. It is blocking the window in the crankcase hole. Do these weights replace the stock flywheel or is the stock flywheel just behind this Moose weight. If it isn't is there any other way I can find TDC again?

Thanks for any help.

Since you're adjusting your valves, you have the tank off. Remove the spark plug and use a Phillips screwdriver or a piece of plastic or wood rod long enough not to disappear down the hole, and carefully locate TDC by feeling the top of the piston. Do so carefully, as the crank will rotate 5-10 degrees as it goes over the top without moving the piston a great deal.

To be completely accurate, you would make a mark on the rod, or better still, use a dial indicator or a solid stop, at a point just before TDC. Mark the position of the flywheel, and then move the piston to the same postion just after TDC, and mark the flywheel there, too. TDC will be exactly half way between the 2 marks on the flywheel. But you don't need to go to all that to set the valves.

Yes, most bolt-on weights have a center that bolts over the outside of the stock flywheel and very often covers up the timing marks. Just another reason I like the weld-ons like the Dr.D and Yamaha's GYT-R flywheels better.


Thats a great idea! Thanks.

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