Villiers head gasket

[gribley]

Over the last 55 years I have owned and ridden many villiers powered bikes (and a villiers powered car). They all had one thing in common, oil dribbling out of the head gasket.
My "Blue Meanie" sprint bike with a kart barrel, the head gasket just spat itself out so I resorted to a smear of sealant and no gasket. OK for half a meeting and then it would squeek.
I have been working on an aprillia 125, the head gasket is an O ring so decided to try one on the greeves. i put the head in my lathe and cut a groove for the o ring, put the head on and torqued it down. Bingo, no squeeks, no dribble and I can take the head off and not have to replace a gasket

[dave higgins]

Nice point gribley, & good tip, glad to see u`r getting involved...

[Brian Thompson]

That's the spirit!

....what he said.....

Nice one Mr Gribly.

Brian.

[gribley]

it's a mod that will work for any bike and it's invisible to the "rivet counters"

[dave higgins]

Rivet counters..... on here!.........honestly......

[Brian Catt]

Yes it's a good method, and by varying the depth of the ring, you can lower the CR if you want. This is exactly what I did to tame my OSSA 6 Day replica a little, but then I could buy several depths of ring over the counter.

[46T Sprocket]

Sounds good. Is there a particular type of material that the O ring is best made from that you used?

http://www.metrogasket.com/o-rings/material_selection_guide.htm

David.

Over the last 55 years I have owned and ridden many villiers powered bikes (and a villiers powered car). They all had one thing in common, oil dribbling out of the head gasket.
My "Blue Meanie" sprint bike with a kart barrel, the head gasket just spat itself out so I resorted to a smear of sealant and no gasket. OK for half a meeting and then it would squeek.
I have been working on an aprillia 125, the head gasket is an O ring so decided to try one on the greeves. i put the head in my lathe and cut a groove for the o ring, put the head on and torqued it down. Bingo, no squeeks, no dribble and I can take the head off and not have to replace a gasket

[gribley]

I used a 72mm bore 2mm section Viton o ring (about a fiver for 2 from simply bearings)