i have been trying to get a friends Mk3 going for quite a while and the engine is finally out being overhauled
At first engine seemed to run on one cylinder and then the other so first thing was to remove carbies and clean out
The carby washers inside had started to fall apart and i thought this may have been blocking the jets
so ultrasonic cleaned them and refitted and there was a fair amount of rust in them
on viewing the inside of the tank it was rusting so this was removed by owner and cleaned out
engine still was running badly so reset tappet clearance and found one tappet right out of adjustment
Reset the tappets, still running badly so checked magneto points cleaned and reset them
still no good
i removed the whole point assembly and compared it with my Mk1 it was completely different and later was told it was from a bth magneto and was the wrong direction clockwise rotation
So we ordered the correct point and lobe assembly and refitted still no good
i was convinced by this time it was the valve timing and convinced the owner to let me rip off the front cover and check found the valve timing was out by 2 teeth so reset valve timing
started the engine it was much better but still not quite right still missing on lh cylinder
at this point i was ready to give up and told the owner to strip it completely to check for valve burnt etc
He agreed so pull off lh cylinder head and found a bent pushrod and i thought at last we found it but on further removal of pistons i found there were no piston rings just oil scraper ring fitted in multiple in each ring land
The moral of this story is if u want to fix something u really do need to strip and check each part unless u want to spend countless hours theorising on what u think a fault is and if u were paying for labour hours it may end up a very expensive exercise
