520 Valve Adjustment

[knobbiethrower]

Well,this ex two stroke guy just attempted to adjust the valves for the first time.Followed instructions from a previous post and got to the point of loosening the tappet nut on the intake valves, tried to get .004" feeler under and couldn't.Backed the screw all the way out, still can't get the feeler under.Repeated process for locating TDC about 10 times with same results. Need help and advise please. I realize I must be over looking some simple thing, just need to be pointed in the right direction.:think

 

[Shaw520]

You, could be at TDC, but on the wrong stroke, watch the valves carefully while slowly turning the engine over, this is best done by rotating the flywheel, cause you can get the engine to turn slowly. The spot you want come RIGHT after the intakes close, look into the 'crank locking bolt hole' and you will see the recess where the tapered bolt fits in.

 

[knobbiethrower]

Shaw520, I took ignition cover off and the pickup on the flywheel is posistioned exactly above the stator as it shows in the engine maintenance manual. I have watched the valves open and close many times.The point where I am now is the intake valves are starting to open.This is where I should be correct?

 

[Shaw520]

Knobbie T, No, the spark is pre-TDC, dont go by that.
You want the point exactly after the intakes close, use a plastic straw in the spark plug hole to watch the piston, right after the intakes close and the piston is at its highest point in the stroke.(TDC):)

Right after that, the auto-de-compression puts pressure on the exhaust valves, wrong spot (NG):(

Send me a PM if you like, and I'll try to be more specific.

 

[Anssi]

Originally posted by knobbiethrower
The point where I am now is the intake valves are starting to open.This is where I should be correct?

Nope. The intakes start to open after the TDC between the exhaust and intake strokes. You want the TDC where both side valves have been closed for quite a while (compression stroke) but way before the exhausts open.

 

[Anssi]

Also, check out this thread on holeshotforum.com. There's a whole bunch of discussion on this topic on there.