Spray silicone lube works as well if you don't have WD40 handy...
Brent, thanks for sharing the details of how you are tightening up your setup.
I am surprised that you had piston to head contact without damage.
I am glad I don't have the money for these high performance motors as these decisions could drive you nuts given a bit of risk is involved when you go too tight and start breaking expensive parts.
If you go too loose you lose performance but, you can spend more money to redo it and tighten the clearance until you pick up that performance. Based on an educated guess that your too loose. But, if you're educated guess is wrong then I am guessing broken parts happen.
That is really why experience is the best teacher and the rare air breathed by those that know how to build a motor that is giving you very high performance while remaining reliable.
Some engine builders share some knowledge but, knowing what the shape looks like for a proper port on a 550 is different than a 650 or 750.
It is great that so many are willing to share what they have done that works. It saves lots of experimentation.
When you are making a living doing head work and motor builds, then it pays not to share how and what all you are doing...
While I probably will never own a track bike or very high performance SOHC4 I do appreciate learning of the engineering involved in building the racing vintage bikes.
