oookay........ Problem was the oil feed in the cylinderhead was closed. RockerArm ceased because of the lack of oil and kept pusing the velves down and the piston came up and hit it . Head cracked on the 3rd chamber, piston got beaten up badly.

Took the head in for some welding, skimmed the piston and fitted new velves. Started up fine... BUT the bottom back breather , breathes smoke and alot. Took it for a spin and no smoke come's out of the exuase. but when I rev it up to 7000 + it smokes up the whole cabin .

Now I went and talked to a few people and they said I should close up the breather and that it is normal for the motor ? Any comments? i'm so disgusted with this project.

Thanks

In that case it must have been a velve that was "faulty" bought the head second hand and i gues you never really know what you get. i was revving about 7500 when the velve said cheerz .

Ive got standard a14 with webers and extractors,reco'ed head recently and valve bounce is just under 7500. seams to make power all the way up to there but never dyno'ed it so im not sure.

i went to 7500rpm one night and bew the dipstick clean out. i got a standard A14 well im pretty sure its standard(didnt make too much power when it was on the dyno 61.4rwhp) so that is the most i have ever gone. gone pretty close some nights though

Well all is Standard on the gx head with it's double springs, so 8000 won't do any harm ?

I am running a standard valve train apart from linished valves and competiton springs and I rev mine to 8000rpm, not all the time though!!, what springs and retainers did you use?

Guys just wondered...

A finally got a A12GX head, flowed, ported and shimmed
Weber dcoe 40's with matched ports from to intakes to head. Lightend flywheel and 300 deg cam shaft.

All was put on with huge success, but this morning a dropped a velve and wondered what was the maximum you could rev with standard sub assembly?