Britbike forum

Classic British Spares Klempf British PartsBaxter Cycle BritBike Sponsor SteadfastCyclesSRM Engineering Lucas Classic Motorcycle Industrial tec supply Hepolite Pistons The Bonneville ShopLowbrow Customs

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Tridentman
Tridentman
New Jersey USA
Posts: 5,732
Joined: February 2008
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
Rohan 86
quinten 75
Top Likes Received (30 Days)
Newest Members
Daytona72, Kurtis Flying Tiger, Edalfa, SDiff, Chopperbabe
11,846 Registered Users
Who's Online Now
6 members (linker48x, Magnetoman, Al Eckstadt, Lew101, L.A.B., Richrd), 34 guests, and 69 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
#810500 05/27/20 5:05 pm
Joined: May 2014
Posts: 47
Q
qbeanie Offline OP
Britbike forum member
OP Offline
Britbike forum member
Q
Joined: May 2014
Posts: 47
I messed up the socket button head screws supplied with the pump by using the wrong hex key. What is the correct thread size and is there a supplier in the US? Thanks

BSA on eBay
Joined: May 2013
Posts: 8,202
Likes: 184
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,202
Likes: 184
What year is the bike? Strangely AMAL only supply one size of hex screw but the studs changed to unified (SAE) coarse into the casting in 69. If you have the original studs and nuts... reuse those.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Oct 2006
Posts: 4,209
Likes: 82
I
Britbike forum member
Offline
Britbike forum member
I
Joined: Oct 2006
Posts: 4,209
Likes: 82
I would like to know how you "used the wrong hex key."

Were you in a big hurry and gambled that whatever you had in your tool kit "MIGHT work?"



I'm not a robot

Joined: May 2014
Posts: 47
Q
qbeanie Offline OP
Britbike forum member
OP Offline
Britbike forum member
Q
Joined: May 2014
Posts: 47
Bike is a 1967. 4mm and 5/32 are very close. 4mm stripped the hex when applying torque. Reusing studs is the way to go!.

Joined: Jan 2004
Posts: 5,123
Likes: 103
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,123
Likes: 103
You can get various socket head screws from McMaster.com. Are you taking the pump apart or replacing the mounting screws? The assembly screws are button, only one mounting screw is button which should be a 3/16" hex. Unknown what screws they used for the body.

Joined: Jan 2004
Posts: 5,123
Likes: 103
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,123
Likes: 103
So you are talking body screws. A 5/32" would be sloppy if they are 4mm.

Last edited by DMadigan; 05/28/20 2:09 am. Reason: unnecessary comment
Joined: May 2014
Posts: 47
Q
qbeanie Offline OP
Britbike forum member
OP Offline
Britbike forum member
Q
Joined: May 2014
Posts: 47
three button hex socket screws were supplied with a new pump. The 4mm hex key fit the screws and all three were evenly snugged up. Switched to the torque wrench with a 4mm hex key socket. Torqued all three to 4 ftlb no problem. Tried to torque one to 8ftlb final spec and the hex key stripped the socket head. Tried the 5/32 on the other two and the fit was better. I never had much luck with button heads and was apprehensive about using them.

Joined: Feb 2014
Posts: 916
Likes: 138
C
Britbike forum member
Offline
Britbike forum member
C
Joined: Feb 2014
Posts: 916
Likes: 138
Hi
As 5/32in. = 3.96875mm I cannot see how a 4mm allen will damage the hex screws unless they were made of cheese?
I have used 4 mm allen tools in 5/32 Fasteners for many years and never had an issue
The button head allen screws supplied with the SRM pumps is a change, the ones I fitted some years ago had conventional allens with 3/16 hex ?
Some weeks ago when I got an A10 bottom end back from them which had one of their pumps already in it they supplied new button head screws, I did not use them just put back the originals with flat washers and threadlock

John

Joined: May 2013
Posts: 8,202
Likes: 184
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,202
Likes: 184
Originally Posted by qbeanie
Bike is a 1967. 4mm and 5/32 are very close. 4mm stripped the hex when applying torque. Reusing studs is the way to go!.


It’s the best way, not as easy to fit the pump/worm gear but I think a better solution the studs are tight into the crank case and the pressure is applied via the nuts (which are 2 aerotight nuts and a nut with tabwasher according to the Manual) 8ft/lb isn’t much torque and I’ve had the Allen screws slacken (only
Once mind... i bought my pump when they shipped them with cap screws so I drilled and lock wired mine into place).


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Oct 2008
Posts: 7,319
Likes: 166
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2008
Posts: 7,319
Likes: 166
Originally Posted by chaterlea25
Hi
As 5/32in. = 3.96875mm I cannot see how a 4mm allen will damage the hex screws unless they were made of cheese?
It's SRM, the same folks who make OPRV pistons out of cheese stainless!


Knowledge speaks. Wisdom listens.

72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
92 BMW K100rs "Gustav"
Joined: Feb 2014
Posts: 916
Likes: 138
C
Britbike forum member
Offline
Britbike forum member
C
Joined: Feb 2014
Posts: 916
Likes: 138
David,
I have fitted quite a number of SRM pressure relief valves and have not had a problem
I would be 100% certain that they do not make their own button head screws

John

Joined: Jan 2014
Posts: 1,634
Likes: 177
N
Britbike forum member
Offline
Britbike forum member
N
Joined: Jan 2014
Posts: 1,634
Likes: 177
DavidP has problems with everything BSA.

Joined: May 2013
Posts: 8,202
Likes: 184
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,202
Likes: 184
Originally Posted by chaterlea25
David,
I have fitted quite a number of SRM pressure relief valves and have not had a problem
I would be 100% certain that they do not make their own button head screws

John


Have you ever stripped one down again John? I didn’t know there was anything wrong with the one I had fitted until I stripped it apart and found it was stuck in place. Out of 3 I have seen taken apart they look like someone has rubbed the sides against some 80 grit.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Aug 2015
Posts: 1,790
Likes: 48
A
Britbike forum member
Offline
Britbike forum member
A
Joined: Aug 2015
Posts: 1,790
Likes: 48
Never ever have stainless bearing on stainless, it will always pick up even with copious lubricant. That's the reason we use copper grease on stainless nuts and bolts.
If I was making a stainless OPRV I would make a stainless body and a cast iron or mild steel piston


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
GM500 sprint bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Joined: Feb 2014
Posts: 916
Likes: 138
C
Britbike forum member
Offline
Britbike forum member
C
Joined: Feb 2014
Posts: 916
Likes: 138
Hi Allan,
When I first read your postings some years on the problem I removed the one from my own A10 SR and found it was fine
Customer engines are so far touch wood still running without complaint
I agree with Andy about different materials being a better option

John

1 member likes this: Allan G
Joined: Nov 2012
Posts: 2,210
Likes: 79
K
Britbike forum member
Online Content
Britbike forum member
K
Joined: Nov 2012
Posts: 2,210
Likes: 79
Merely a thought,
But in a situation completely flooded with pressurised oil (surely must be one of the most oil-flooded parts) the issue of metal to metal aggravation should be minimal?

Joined: May 2013
Posts: 8,202
Likes: 184
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,202
Likes: 184
Originally Posted by koan58
Merely a thought,
But in a situation completely flooded with pressurised oil (surely must be one of the most oil-flooded parts) the issue of metal to metal aggravation should be minimal?

You would think so, but it depends on clearance relative to the viscosity of the oil. If the oil is free to pass down the side of the piston it isn’t going to do much in holding back the pressure, instead it would dribble down the side and start leaking off early, more so as the engine oil gets hot and the viscosity is at its minimum.

Lyford classics (A10 specialist) makes stainless bodied ball type pressure release valves. At the time there was a lot of hoo-ha about ball type being no good (before Dave maddigan did his testing on them) so I found some NOS piston types and fitted one of those. A while later my friend was suffering with the oil light on his OIF, we checked the oprv (SRM) and it was also galled, he fitted a lyford classics item and it solved the issue with the light coming on. The ball and spring are different on lyfords to the original BSA, the spring also looks stronger although I have never done a pressure check to see at what point it blows off.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)


Moderated by  Allan G, Jon W. Whitley 

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