I need to set the valve on a OHV Honda GX340 engine, book says .006 In/.008 ex, cool, no problem. Says to take the engine to TDC on compression and set the valves.

I do that.

But when I rotate the engine off TDC to the base circle of the cam, my valve clearance gets really big, probably .025 or so...

Anyway, I'm wondering whether the clearance should be set on the base of the cam, as opposed to the overlap of the cam?

The only solid lifters I set now are on my 235, but I do it with the engine running and feel the drag on the feeler gauges, so I'm not sure if this is normal.

Seems to me that the large clearance when not on the overlap of the cam is to excessive, anyone care to share some knowledge?

Could it be that the cam is worn?

 

Valve lash is always set with the lifter off the lobe. When #1 is at TDC both valves should be closed. You could have had the engine 180 degrees out.

Easiest way to make sure the #1 TDC is on the compression stroke is with the spark plug out and a finger is over the plug hole. When you rotate the engine, you will feel the compression push past your finger. Line up the timing mark since it could go a little past at start setting the valves. Each cylinder you adjust the valves on must be on TDC of the compression stroke.

 

he's right, you got it backwards. both valves should be fully closed when you set the lash.

 

Thanks guys. The GoKart will live as soon as I can find a centrifugal clutch that will handle 11HP and not cost a fortune