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Old 06-09-2010, 10:49 PM
meowy84 meowy84 is offline
Motorized Bicycle Elite Member
Join Date: Jul 2009
Location: Canada
Posts: 238
Default Re: blueprinting not hotrodding

You're right, a little extra compression won't hurt. Good to hear that there's no contact in your engine. I might try removing a gasket myself. But I'll do some testing first. Since thousands of an inch make all the difference here and the machining on these engines not so wonderful there's also the stretching of the rod or the slack/tolerances in the bearings being changed (slack being taken up) at the point when the piston with all its inertia hits TDC. There might be no contact when the engine is just turned over by hand but contact when it's actually running. Best and simple thing to do is use a piece of plasticene/playdoh (heck even bubble gum will work LOL) and see just how much room you have at TDC between the plug and the top of the piston.

Also a lot depends on the plug you use and how far it protrudes into the combustion chamber. Another thing is the orientation of your spark plug's ground electrode when it's tightened in the slanthead. Depends on how the threads were cut at the factory and how tight you tighten your plug sometimes the ground elctrode might be sticking out at the top closer to the roof of the head's combustion chamber (so no contact), sometimes it might be sideways (no contact) and sometimes it might be closer to the piston (contact) and cause interference with the piston on engines where the piston top comes very close to the roof of the combustion chamber.
McGyver could fix that with bubble gum.

Last edited by meowy84; 06-09-2010 at 10:52 PM.
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