Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
BikeVice
BikeVice
San Rafael, Ca.
Posts: 580
Joined: May 2009
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Previous Thread
Next Thread
Print Thread
#840203 02/16/21 2:59 pm
Joined: Aug 2012
Posts: 260
W
Woodsie Offline OP
Britbike forum member
OP Offline
Britbike forum member
W
Joined: Aug 2012
Posts: 260
I took the OPRV out of my 75 T160 and it does not have a screen. Is this an issue? or is a new OPRV recommended? thanks,

Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Woodsie #840232 02/16/21 10:07 pm
Joined: Jan 2004
Posts: 4,950
Likes: 70
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 4,950
Likes: 70
I think the screen is more to differentiate it from the twin OPRV. If anything as large as the screen mesh holes went through the pump you would have other problems.
I have not had a screen out but the shell that holds it may also be what keeps the piston in against the spring. You should check that.

Joined: Aug 2012
Posts: 260
W
Woodsie Offline OP
Britbike forum member
OP Offline
Britbike forum member
W
Joined: Aug 2012
Posts: 260
Thanks for that Dave. Upon closer inspection I believe the shell is still in place and the piston does seat against it. I see some marks that may indicate that the mesh has been removed. There is the number 70 stamped into the top of the domed nut. What does that signify?

Joined: Sep 2001
Posts: 1,310
Likes: 19
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Sep 2001
Posts: 1,310
Likes: 19
70 psi rated, triples are 90 from memory....maybe you have a twin OPRV? I think they are 70.

Joined: Mar 2006
Posts: 4,848
Likes: 43
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,848
Likes: 43
Originally Posted by tridentt150v
70 psi rated, triples are 90 from memory....maybe you have a twin OPRV? I think they are 70.

Triple OPRVs have coarse mesh and are stamped '70'.

https://www.classicbritishspares.com/blogs/news/service-bulletin-oil-pressure-relief-valve

Joined: Oct 2008
Posts: 7,042
Likes: 112
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2008
Posts: 7,042
Likes: 112
I just replaced mine. The old one had the coarse screen and 70 on the end cap. The new one from Harris has a fine screen and nothing stamped on the cap.
Cold starting pressure is now over 120psi, so I assume that it's the correct OPRV.


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
Woodsie #840271 02/17/21 10:30 am
Joined: Sep 2001
Posts: 1,310
Likes: 19
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Sep 2001
Posts: 1,310
Likes: 19
Manual states 90 psi....interesting...I'll have to go down to the shed and see what mine has on it.

Joined: Mar 2006
Posts: 4,848
Likes: 43
L
Britbike forum member
Online Content
Britbike forum member
L
Joined: Mar 2006
Posts: 4,848
Likes: 43
Originally Posted by tridentt150v
Manual states 90 psi....interesting...I'll have to go down to the shed and see what mine has on it.

Not the easiest thing to get a photo of, but it is stamped '70'.
[Linked Image from i.postimg.cc]

T160 Manual states
"Oil Pressure Relief Valve
Release pressure 85-75 p.s.i."

BSA A75 manuals state "Blow-off pressure (oil at 80°C) 70-90 lb./sq.in."

L.A.B. #840283 02/17/21 1:58 pm
Joined: Aug 2012
Posts: 260
W
Woodsie Offline OP
Britbike forum member
OP Offline
Britbike forum member
W
Joined: Aug 2012
Posts: 260
Thank you all. I am going to install a new spring and call it good. Thanks


Moderated by  Tridentman 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5