I just replaced the bearing on a os 61 four stroke. When I took the engine apart I didn't pay attention to the position of the cam in relationship to the pistion. Can anyone give a breif discription of the assembly so I get the timing correct. I notice on the cam gear there is a small dot next to the gear. Does this need to be in a specific position in regards to the piston position?? Any help will be appreciated....

SETTING CAM TIMING ON A REAR CAM OS 60 OR 90

With the piston at Top Dead Center, you position the ring gear that's in the rear housing such that the embossed "dot" is straight up, towards the cylinder head.

Look at the gear carefully. You'll see four things that look like the "dot". Three of them are the ends of the screws that hold the ring gear to the assembly, and between two of the screws is the "dot".

You'll have to remove the small cover from the rear of the rear housing to hold the assembly to keep it from rotating.

FOUR STROKE TIMING FOR FRONT CAM OS TYPE ENGINES

The proper way to set the timing in all O.S. single-cylinder four-stroke engines with the front camshaft is:

1) Rotate engine so that the piston is at Top Dead Center.

2) Locate the timing mark on the side of the cam gear.

3) Insert the cam gear so that the timing mark is in a direct line with the center of the cam followers and the centerline of the pushrods. It is NOT at a 90 degree angle to the crankshaft. The angle will be slightly back.

4) Replace the cam cover and you're ready to go!

enjoy,

jim

Thanks, That did it......Mike