the inner o ring groove on the barrel of my 1997 gasser has a problem.The out side edge of the groove has been broken of in 3 places.each of the gaps is a bout 10mm wide. Can you lot out there give me some ideas? is it a new barrel or will the o ring still seal?

cheers, steve

Edited March 5, 200620 yr by gasgasssser

chemical metal maybe?

i would have though the head would still seal as the o ring is still getting clamped down?

James

I would try and drop an email to John Shirt

(gasgas uk)

he will most probably try to help.

I have always found him helpful.

I am assuming this is on top of the cylinder and is the inner seal, closest to the combustion? if so, sounds like trouble.

I design hydraulic systems, which use lots of o-ring joints.

O-ring won't seal without the outside surface to push against. The o-ring itself can't take much pressure. It seals by clamping in some applications like drain plugs, side case covers, etc, but only minor pressure loads

For pressure applications, it doesn't seal by clamping action. That only squeezes it tightly enough to seal the first part of the pressure rise. Then the pressure pushes the oring outward into the walls and back of the groove, effectively creating its own seal by pushing against those surfaces.

Lip seals work with 'pressure energizing' also.

tire plugs work in somewhat the same way, except not in a groove.

Without the back wall of the groove, I doubt it will hold much.

Could it be welded up and remachined? probable exceed the cost of new?

The liquid metal sounds feasible is you know somewhere to have it machined. The groove needs to be smooth, with radiused corners where the bottom and outside meet.

k

Thanks for all the replies.I sort of know i`ve got a problem here.

I`m just trying to work out why the inner o ring is needed.if the head is sealed properly on the barrel and the outer o ring is ok,where can the coolant actually go??

into the barrel

hmmmm How?

all of what you say makes a lot of sense,the o ring is there for a reason,but if,as you say the inner seal is dodgy,isnt the next "barrier" the seal between the head and barrel which is 2 precision machined faces clamped together to form a gas tight seal??

I`l get round the problem somehow,thanks again fellow trials riders,have a good 2006.

i way quoted by the guys at GASGAS UK,

360 sheckels is a lot of money.

Sounds like welding/machining would be cheaper.

The welding process typically warps the barrel and reboring or replating may be neccessary after a weld repair that close to the bore.

I know a TIG welder who can butt weld 14 ga stainless without a blue shadow next to the weld.

A good welder with some heat sink putty (or similar) can keep the heat very low and very localized.

aptech in glouster will fix it for cheaper

GasGasser told me that he has now fixed the problem

apparently gasgas told him to use an expanding/flexible (something gasket) gasket sealer, as aparrantly the head holds just about all of the compression in the chamber

and he says he hasnt noticed a much of a difference,

nice cheap and easy fix,

which ill remember !

Its fixed .The head and barrel fit together to make the seal.(Primary seal)The oring is a secondary seal to stop any stray gasses escaping.(got that inf from gasgas)I lapped the head and barrel faces,then dumped the inner oring and replace with flexible gasket sealer Acording to gasgas the pressur of water is 12 psi or less,so it will do the job,in fact it is doing the job,been out on it for about15 hours(not all at once).Running like a new`un

total cost