AJS & Matchless Owners Club

I have a Welworthy piston, that is fitted to my +.040" G80CS (long stroke) barrel. The J.P. rings that were provided are too deep for the grooves in the piston and therefore stand proud of the piston by approx .030". A very talented person would cut the grooves a bit deeper, I I would rather find the correct ring set, .111" radial depth. Any advise as to where to search woudlbe greatly appreciated.

Welcome to the club and Forums, Bill.
I don't know of anywhere in the U.S.A. although I think there's still the original importer of the G80CS bikes in the USA but can't think of his name at the moment. No doubt someone will add that info if you don't already know them.
I may be thinking of Walridge Motors in Canada who I believe have spares for British Classic bikes.

https://www.walridge.com/

In the U.K. Thorntons are a 'Go to' supplier for pistons and rings and very helpful. I'd suggest asking them by email with details of your piston.

https://www.fwthornton.co.uk/?gclid=Cjw ... y4QAvD_BwE

You are probably aware that the Club spares dep't stocks complete pistons and some ring sets.

https://www.amoc-parts.com//store/comer ... r2=&user3=

you need imperial rings , if you are stuck send cox and turner a message , they can do a set . obviously postage will be a problem
If not search for a set of original on ebay
All modern pistons will have metric rings

https://www.coxandturner.co.uk/piston-rings/

No joy at the AMOC, Thorton, while Walridge sent the worng set and has no access to the correct ones. Have submitted an enquiry to Cox & Turner to see what they might have.
Best,
Bill

absolutely guarantee cox and turner will sort it out , always come up trumps

All sorted, found a skilled machinist able to cut my Welworthy piston to fit the JP rings. Thanks to all for your input.

CSBill,
Please share details. What's the ordering number of the JP rings (compression and oil scraper rings)?

I noticed JP supplies pistons for 1956-59 CS engines. Piston rings are 2x1/16" and 1x4mm scraper. 1960- on pistons have the same rings, I guess. This is specification shared by the late 650CSR as well as the BSA DBD34.

I wonder if gapless rings can be made to fit. They are particularly interesting for high CR engines.
Cheers,
Knut