Any tips on adusting the tappets? Never done this before. Iknow the recommended range - Iassume both valves should be adjusted to the same gap thickness, and that the adjustment is done with the valve is closed.

Is there an advantage to a smaller or larger gap? Or should Ijust go right smack in the middle?

Thanks.

I usually set mine in the middle of the range but that's because I happen to a feeler gauge that is in the middle of that range. </p>

Just bring the engine to TDC, you'll feel it kind of click into that position, and there should be no tension on the rockers. Then put your feeler gauge between the rocker and the valve tip and slowly tighten the adjustment screw until you feel a light drag on the feeler gauge as you pull it out., and I mean a LIGHT drag on it.</p>

The other way is to rotate the prop until you see one valve open the whole way and adjust the closed valve.</p>

</p>

What happens if the gap is too big, too small, and/or uneven? Just wondering how this affects performance and what is a sign that adjustment needs to be made.

I found the tappet clearances to be slightly different and tightened the looser one to match the clearance of the tighter one. The range is .04 to .1 mm, and right now they are set at .05mm.

Thanks for the help.

From Troy Newman on http://www.patternflyer.com/troy/?p=92 :

...<span style="font-size: small; font-family: Times New Roman;">Theyshould be set about 0.002”-0.004”. I find the factory doesn’t alwaysget these set the best. I run mine as tight as they will go and stillhave the valve closed. You can wiggle it and feel some gap but it istoo small to measure. If you can tell what you are doing you don’t needa feeler gauge to check it. If you are a sledge hammer mechanic thatcan break and anvil with a rubber hammer, PLEASE use a feeler gauge.Its very important the valve closes. If it doesn’t the piston could hitit and cause major damage to the engine. Really the only thing you willnotice with the tappet clearances too loose is that top end power willbe slightly reduced. Not major but a little. The clearances don’treally affect idle, transition much just the top end power. This justmeans the valve is not staying open as long. So it’s not getting as bigof charge before the valve closes and it makes the Boom. ...

</span>I use a similar method. First the engine must be at top dead center, piston at the top of its stroke and both valves closed. I loosen the lock nut and back the adjustment screw off about one (1) turn. I then place my index finger on one end of the rocker arm and my middle finger on the other end and "rock" the arm while I slowly tighten the screw. When the play just disappears,  I open the adjustment 1/4th turn from where the clearance JUST disappeared.<span style="font-size: small; font-family: Times New Roman;"> </span>Tighten the lock nut and your done.<span style="font-size: small; font-family: Times New Roman;">
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