Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsSRM EngineeringGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supply



BLACK FRIDAY MEMBERSHIP OFFER 2021



50 % DISCOUNT ON ALL OPTIONS!!!


Upgrade your membership: Premium Membership Gold Membership Life Membership

50 % DISCOUNT ON ALL OPTIONS!!!



New Sponsor post
The BLACK FRIDAY SALE is here!
by The Bonneville Shop - 11/23/21 5:29 pm
New FAQ post
How to find my own threads?
by reverb - 11/20/21 3:55 pm
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
umjwh
umjwh
Lowell, Ind
Posts: 53
Joined: February 2006
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
Rohan 74
NickL 73
Top Likes Received (30 Days)
Newest Members
Gus_Carrero, mogmike, Julian1966, BSACliff, Bezza Frank
11,920 Registered Users
Who's Online Now
3 members (Magnetoman, Tridentman, Doug P), 23 guests, and 20 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Joined: May 2014
Posts: 48
Q
qbeanie Offline OP
Britbike forum member
OP Offline
Britbike forum member
Q
Joined: May 2014
Posts: 48
After a long delay I’m starting back to replace the old carbs with new. After removing to old carbs, I found an oring, thin paper gasket, and a slightly thicker (~1/8”) fiber gasket. I assume the fiber gasket is an insulator. Is the paper gasket required as the new carbs were only supplied with an oring?

Also a split washer is missing on the studs. Is there a specific washer to be used or can a washer sourced from oval hardware be used.

Thanks in advance

BSA on eBay
Joined: Nov 2018
Posts: 101
Likes: 24
50+ years experience
Offline
50+ years experience
Joined: Nov 2018
Posts: 101
Likes: 24
Generally the paper gasket is placed against the cylinder head, then the insulating block, then the o-ring in the cut groove on the carburetor mounting flange. The parts book shows a 42-4476 5/16-26 Nyloc nut as original fitment. 42-4476 supercedes to 37-1691. A split washer would not be called for in this application, however it would be recommended to use a thin flat washer under the Nyloc nut.
-Dave


[Linked Image from thebonnevilleshop.com]
2 members like this: joe czech, Allan G
Joined: Aug 2001
Posts: 5,694
Likes: 80
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Aug 2001
Posts: 5,694
Likes: 80
With Dave all the way, except that the original nuts were not Nylok in 1967. Nevertheless, Nyloks are definitely the way to go, as these nuts should be tightened only a tad past finger tight, maybe 5-6 ft. lbs., so as not to distort the flange on the carb.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Joined: May 2004
Posts: 5,020
Likes: 116
B
Britbike forum member
Offline
Britbike forum member
B
Joined: May 2004
Posts: 5,020
Likes: 116
FWIW .
I use a soft ish thich compound gasket between the Tuffnol & the body so dispense with the O ring
I think Enfieds had no O ring .
The softi gasket dforms into the o ring hole to make sure the carb is saled and the fact the flange is supported under the studs aids in preventing flange warping ( as goes thin nuts & a gentle touch )


Bike Beesa
Trevor
Joined: Mar 2019
Posts: 34
Likes: 6
J
Britbike forum member
Offline
Britbike forum member
J
Joined: Mar 2019
Posts: 34
Likes: 6
FWIW, i upgraded my 66 spitfire with new AMAL premiere's and used a 1/8 insulator sandwiched between two paper gaskets, plus original locknuts (w/ no washers pre factory). whether paper or O-ring, most likely it doesn't matter - just don't use an O-ring with a gasket on the same sealing surface. i used a paper gasket because i feel it seals better than O-ring against the phenolic insulator. fairly sure O-rings are designed for sealing against a metal surface. (just my personal preference and my 2-cents).

Joined: Dec 2004
Posts: 11,445
Likes: 193
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,445
Likes: 193
I use a spring split washer under the nyloc, as I tighten I stop as soon as the spring split washer is flat I stop turning the nut. Never had a flange bend or a carb coming loose since starting this scheme. I use carb with O ring, double thickness 1/4" heat insulator, paper gasket, head.


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