setting timing on a 4 stroke

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#1
Forgive me for being a newb here...im used to 2 stroke simplicity.

I have the oppurtunity to pick up a 1984 Honda XR250 for $100. Everything is good on it except for one thing....when he went to do some work to the head, he dropped the timing chain.

So....I need to put it back on and set the proper timing. I have never done this before. I figured I would just set the piston to top dead center and make it so the valves are closed when I hook it back up. Will this work? It seems like it should be more complicated than this. How do i do it?
 
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VenomRS4 said:
I figured I would just set the piston to top dead center and make it so the valves are closed when I hook it back up. Will this work? It seems like it should be more complicated than this. How do i do it?

Venom.

It's not too much more complicated than that.

Remove the two inspection caps on the left side dyno cover. Find a socket to fit the bolt in the center hole, I believe it's a 17mm. Use this bolt to turn the engine over.

Find top dead center by carefully placing a long thin screwdriver down the spark plug hole and rocking the engine back and forth. Then look in the small inspection hole and line up the tdc mark on the flywheel with the mark on the case.

With the engine at tdc, place the cam in the head with the cam lobes facing down towards the crankshaft. Install the cam chain and cam chain sprocket. There are two lines on the outside of the sprocket. Those lines line up parallel with the rocker cover gasket surface on the top of the head. If they don't line up, move the cam chain back or forward on the cam sprocket until they do. Lock tight the cam sprocket bolts and install the rocker cover. Adjust your valves to .002 thousands on the intake side and .003" on the exhaust.

Good luck.