Villiers 6e/8e Pistons

[stickinthemud]

I have a 6E 197cc Villiers engine and I'm looking to increase usable power.

One way is to use a 1H piston and bore the barrel out to 225cc.

I managed to get hold of a standard 1H piston, not an easy item to find.

My dilema is the piston weight and increased imbalance of the crank.

The old standard 197cc Villiers piston weighs 250g.

I rebored it to +20th for a Hepolite dykes ring piston when I got the bike and this piston weighs 275g.

The 1H Villiers piston I have weighs 300g!

The thought of an extra 2oz/50g flying round at 4000rpm is a bit worrying.

Even with the Hepolite piston, which I now assume to be a racing piston for Karting, there is quite a bit of vibration.

What will it be like with the 1H piston in it?

Anyone any experience of engine balance or Villiers 6E/8E bobweight flywheels under this level of stress?

Any thoughts?

Edited September 12, 2010 by Stickinthemud

[hammertight]

Hello there! I would say don't worry about piston weights. In about 1992 I got a 1H piston from Mick Wilkinson, and an engineer in Harrogate by the name of Jepson bored the 6E barrel for me. The piston was I think 20 thou oversize, and Mr Jepson was a bit dubious about the barrel taking the bore! However, he carried on and now, eighteen years later, that piston is still going strong in that same barrel. I do replace the rings when necessary, with original old stock from Steve Gollings of Villiers Services. I might add that at that time I too was a member of the great Yorkshire Classic Club, and the 1953 Earles forked Dot with the 1H piston won the 2 stroke Championship three times in a row from 1993. ( no such thing as a vintage 2 stroke class then) So no pressure on you! As regards the bobweights,they provide grip! Ask Mick Wilkinson! I hope you get great fun with the "big engine" Best Wishes.

Edited September 26, 2010 by Hammertight

[stickinthemud]

Thanks for the reassuring words Hammertight.

I feel better for that.