Running in,- should I worry?

[SPRIDDLER]

Oh dear, quite deep by the look of it, and the valve recess on the piston has also been pitted, although that's not especially a problem unless piston scrapings are free to roam. Or could the pitting marks be evidence of pre-ignition as the 'sharp' angled edge between the valve recess and the flat piston top could be a hot spot

Ibs piston.JPG

[Ib-Denmark]

Oh dear, quite deep by the look of it, and the valve recess on the piston has also been pitted, although that's not especially a problem unless piston scrapings are free to roam. Or could the pitting marks be evidence of pre-ignition as the 'sharp' angled edge between the valve recess and the flat piston top could be a hot spot

Ibs piston.JPG

The "pitted area" is not so bad as it look in the picture I removed it with a dry cloth.
But I will of course discuss it wit the workshop.
Ib

[JEAN-NOEL]

"Piston clearance as the vendor (GPM) recommends"

When I bought GPM +40 from AMOC Spares there was no instructions leaflet in the boxes.

Derrick, from T&L Eng. said me that GPM pistons need a bit more clearance than stated in the workshop manual, and the barrels were honed to obtain a clearance of 6 thou.

Obviously your left cylinder has seized, and seem to be too tight.

[Rob Harknett]

Let the experts decide what cause of action to take now Ib. At least you have now found the problem. You'll get it sorted out eventually.

[56G80S]

Ib, my sincere hope that your experts can sort this out.

On the positive side I had a piston worse than that on my 1966 14CSR many years ago and it went on to give good service.

Johnny B

[Ib-Denmark]

Ib, my sincere hope that your experts can sort this out.

On the positive side I had a piston worse than that on my 1966 14CSR many years ago and it went on to give good service.

Johnny B

I am HAPPY
The workshop found absolutely nothing to worry about (except a tigth clearance) and the cylinders are now honed up to a 5 thou clearance.
See you in the road!

[Rob Harknett]

Ib, my sincere hope that your experts can sort this out.

On the positive side I had a piston worse than that on my 1966 14CSR many years ago and it went on to give good service.

Johnny B

I am HAPPY
The workshop found absolutely nothing to worry about (except a tigth clearance) and the cylinders are now honed up to a 5 thou clearance.
See you in the road!

It was a tight engine then Ib, Glad its now all sorted.

[56G80S]

Great, my wish for you came true!

Johnny B