Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supply Classic Bike Parts Cheshire

Upgrade Your membership! Premium Membership Gold Membership Vendor Membership

New Sponsor post
New FAQ post
Photos on private message
by Mal Marsden - 06/16/22 7:00 pm
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
Reading UK
Posts: 749
Joined: November 2005
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
reverb 69
kevin 52
Allan G 50
Top Likes Received (30 Days)
Cyborg 29
Newest Members
Ian Scotland UK, cherbini, grahamsmythe, Joe Santelik, Lord Hepcat
12,156 Registered Users
Who's Online Now
4 members (Dibnah, L.A.B., JER.Hill, gunner), 24 guests, and 19 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Most Online151
May 8th, 2022
Thread Like Summary
Total Likes: 2
Original Post (Thread Starter)
#880483 05/13/2022 10:26 PM
by DMadigan
Referring back to this post:
I made the two piece OPRV:
[Linked Image from]
The bearing ball sits against a rubber backed washer, held in by a spiral ring. A hollow set screw sets the pressure on the ball and allows the oil through to the relief hole.
I had to use RTV on the washer because the diameter of the rubber was the same as the bypass slots around the ball. Making the slots slightly less deep will let the rubber seal against the body. In any case there is no leakage with the ball seated.
Being two piece, the body threads can be sealed in the case without potentially blocking the relief hole. A hex is provided on the body for turning it in.
The cap is just a cover.
Liked Replies
#880565 May 14th a 08:38 PM
by Stuart Kirk
Stuart Kirk
The earlier engines can be drilled and tapped for an OP gauge. I've done it several times, even on A10's. I like to use 1/16" NPT for doing it because imho space is limited.

Nice looking valve arrangement but I wonder about the oil pressure pushing against the exposed part of the rubber backed washer. It seems to me it might try to move it some and find a leak path there. Does its retaining clip seat in a groove?

Another concern would be the life expectancy of the rubber seat. Why not use a metal seat like most other relief valves out there? Accurate metal to metal can seal quite well.
1 member likes this
British Cycle SupplyMorries PlaceKlempf British PartsBSA Unit SinglesPodtronicVintage MagazineBritBike SponsorBritish Tools & FastenersBritBike Sponsor

© 1996-2022
Powered by UBB.threads™ PHP Forum Software 7.7.5