ORIGINAL: Edge3644
The cylinder surface looks perfect. Valves seal I checked first by leaving inverted cylinder full of fuel for a night.
None of the fuel escaped through the valves. Then I assembled the engine and keeping it upright I poured some
synthetic oil to submerse the valves. When rotating the crankshaft I looked for air bubbles escaping thorough oil. None.
After short attempts to start the engine, it did not regain compression, but I noticed black resude in crankcase.
Lower side (on one side only) of piston is rubbing against cylider and it is kind of shiny polished/grinded. Although it
shouldn't probably affect compression I suspect that new conrod is bend slightly. Otherwise what would explain piston wear
on one side?.
Wow!...sounds like you've covered most bases...I rather doubt that a new con/rod would be bent ...When you say "No Compression", do you actually mean "None" or "Weak"...Before you can have "Compression" the engine has to ingest air from the intake side...Is everything ok on that side?, rotary/valve timed & rotating properly?....Cam timed correctly?...Throttle open?....Just as a test, might be interesting to try with the entire carb & maybe even the air chamber removed, eliminating everything on the intake side...[sm=confused.gif] on second thought, just lift the cyl.; remove A/C, reinstall cyl. & try...We'll keep thinking...Someone else may join/in...