TOPIC:

Slipping is most likely. I certainly had to replace them on my hill climb Nordwest.

Piston rins broke down I toke the engine of very simple

Most likely this is the need to rectify and bring piston. I am thinking of a 102 mm for the KTM LC4 640

Yes, a Nordwest engine top end strip is really simple once you have the engine out

There is an account of when I did it on my hill climb bike in 'The GeN #7'.

Has Bob Wright not got any standard pistons?

A 102mm piston will take it up to the same big bore 604cc as the Frigerio kit.

Beware that this will leave less mating surface for the head gasket, particularly round the coolant passages at the front. You may have problems with combustion chamber pressure getting in to the cooling system. Use slightly more torque on the head nuts (make sure the studs are in good condition and not stretched). Consider getting a solid copper gasket made up (like the FPM kit).

Good luck with the rebuild.

Where is it?

Bob Wright?
www.bobwrightmotorcycles.co.uk/

The GeN#7?

www.gilera.org.uk/gilera/gens/gen7.PDF

See page 2 of the PDF.

Part 2 of the top end strip down:

www.gilera.org.uk/gilera/gens/gen8.PDF

See page 1 of the PDF.

if you ares till interested in a big bore kit you may get in touch with Gottfried at www.hahne-power.de/english/engl.tuning-teile.htm

@ Pete solid head gasket in copper or aluminium?
What would be the better choice? Any experience?
I am just thinking about getting made a aluminium gasket for my 102mm kit

ciao joachim