I’ve had it rebored and gone up to the first oversize piston.
Whilst it’s apart I’ve decided to renew main bearing and flywheel side seals and gaskets, and fit a sluk head cowling and vortex fan for supposedly better cooling ( I’m a sucker for new bling )
So what caused the seize? The plug and piston crown do not indicate a lean issue or air leak judging by the colour. I pressure tested it prior to strip down and it holds pressure with no leaks.
There was a dark black oil stain on the main bearing retention plate. (Sucking air and oil in from crankcase?)
The carb was jetted professionally on a dyno.
Fuel tap is fast flow and measured rate is OK
A club member has suggested looking at the float valve size - I’ve ordered a 3.5mm fast flow valve from MB. Feasibly at that speed the engine may have been using more fuel thank the float bowl could supply and it drained..?
Also I gather that compression ratio will increase too with the rebore - should I add a headgasket to compensate for this - the gt240 kit doesn’t usually need one …
Once rebuilt I’ll get it redyno'd and dialed in
Any thoughts on the cause, or rebuild hints and tips appreciated
