Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleIndustrial tec supplyHepolite PistonsThe Bonneville Shop

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
Ian C
Ian C
South Yorkshire, UK
Posts: 574
Joined: June 2008
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
#288647 12/12/09 11:21 pm
Joined: Aug 2007
Posts: 290
S
SteveM Offline OP
Britbike forum member
OP Offline
Britbike forum member
S
Joined: Aug 2007
Posts: 290
In a previous thread there was mention of a technical article online that described how to convert the lay-shaft bushings to needle bearings. If anyone has a link to that tech article, I'd appreciate it. I've done a few searches and have found nothing.

I'm also interested in anyone's comments who has experience in incorporating modern lip seals to the outer cover; or whether or not it's reasonably feasible.

Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Joined: Oct 2003
Posts: 11,281
Likes: 26
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Oct 2003
Posts: 11,281
Likes: 26
Anything from a 1970 4-speed gearbox will fit right into a pre-unit gearbox. The only trouble is driving the speedo, so you use a 1965 layshaft.


Don't hide 'em, Ride 'em !!

RF Whatley
NE Georgia, USA
Joined: Aug 2001
Posts: 8,653
Likes: 77
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Aug 2001
Posts: 8,653
Likes: 77
All the bearings, including the needle races, open and closed end, are available from bearing factors, although you may wish to support your local bike part dealer. Full details of bearing sizes are in Unit Triumph manuals. You have to buy bronze thrust washers from a Triumph dealer anyway.

Oil seals on the kickstart and gear pedal sounds like a lot of work, unless you just glue the seals to the casing, where the original spongey "seals" went on some models.

The shafts are above the oil level and hardly any oil leaks from there on mine, with no seals.


Amateur Loctite enthusiast.
Joined: Oct 2003
Posts: 11,281
Likes: 26
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Oct 2003
Posts: 11,281
Likes: 26
The more modern gearbox versions simply placed an o-ring on the k/s and g/s shafts. As TT said, those shafts are above the oil level and the seal is for "splash" only.

You probably don't want to turn a grove into the k/s shaft to implement a seal or the shaft will simply break there. It would be an easy thing to fit the inside of the k/s cover with a groove for an o-ring which sat directly on the shaft.

Take a look at the standard seal setup from the early 70's and get some ideas.


Don't hide 'em, Ride 'em !!

RF Whatley
NE Georgia, USA
Joined: Aug 2007
Posts: 290
S
SteveM Offline OP
Britbike forum member
OP Offline
Britbike forum member
S
Joined: Aug 2007
Posts: 290
Thanks for the input. Really appreciate it.

Joined: Oct 2009
Posts: 684
B
Britbike forum member
Offline
Britbike forum member
B
Joined: Oct 2009
Posts: 684
Dave in NV who posts in the Gold Star page has the setup to cut the groove in the cases and install o-rings, in BSA p/unit gearboxes, you could try him. Don't tell him I volunteered him :>

Joined: Nov 2005
Posts: 1,346
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Nov 2005
Posts: 1,346
Steve, I have used a BSA b-50 kick start seal on the shift shaft on the triumph. It worked on my 500 with the 5 speed box turned so the shaft was under the oil level.Some covers just need to machine a groove for the seal and some need a small amount of weld.


Tim Joyce
sponsors
[email protected] cycles
Works shocks
Glass from the past
Joined: Sep 2005
Posts: 1,566
Likes: 14
G
Britbike forum member
Offline
Britbike forum member
G
Joined: Sep 2005
Posts: 1,566
Likes: 14
Seems like lots of work here for no real gains ? The original boxes are pretty damn tough to start with, and I can't say I've ever had any issues with leaking bushes (providing those bushes are themselves in reasonable nick.)

As for the bearings ? Why fix what ain't broke ? I've done hundreds of thousands of miles with these, and I've had to rebuild ONE, after it had clocked upwards of 80k under MY @rse - and I have NO IDEA how long before my ownership it had been fettled other than the fact that the bike (Daisy) had been refurbished some 9 years or so before I got her ?

Jus' sayin' is all smile


https://www.amazon.com/gp/product/B074C7CZYL?ref_=dbs_r_series&storeType=ebooks

Good judgment comes from experience, but the most memorable experiences tend to come from bad judgment!



Joined: Jan 2005
Posts: 1,644
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2005
Posts: 1,644
I'm with you on this Graham,I think that many owners of these old bikes,want to set up their bikes to racing spec's and then ride them 40-50 mph ,less than a thousand miles a year. A lot of these "so called" upgrades are talking points only for this kind of use. Then, some of us get along just fine with the bike in standard trim. I'm not putting any blame on anyone,as we all have different reasons for messing with these things. Just sayin' Dick

Joined: Oct 2003
Posts: 11,281
Likes: 26
R
Britbike forum member
Offline
Britbike forum member
R
Joined: Oct 2003
Posts: 11,281
Likes: 26
I'm also with Graham.

The big downfall of the Triumph outer gearbox cover is that there is ZERO oil splashing around out there. If there were, then there would be a lot less green goo sitting there, and a lot fewer rusted shifter springs. laughing

So in order to have a leak with any kind of bothersome regularity, you really have to have a loose k/s shaft bush or you have to lean the bike way on over.

beerchug


Don't hide 'em, Ride 'em !!

RF Whatley
NE Georgia, USA
Joined: Jul 2007
Posts: 913
Likes: 1
T
Britbike forum member
Offline
Britbike forum member
T
Joined: Jul 2007
Posts: 913
Likes: 1
If you have the correct tolerance between the kickstart shaft and its bush then you will have minimal oil leakage. As its a steel shaft running on a steel bush they BOTH wear.
I have recently put a new kickstart bush in my box but noticed that the shaft is also worn. It's only a couple of thou but enough to let the oil out.
Of course you could always use the leak as some sort of indicator - when the leak stops it's time to top up the gearbox. grin


"Live the life you love, find a god you trust and don't take it all too seriously"

Pre-units rule!

Mid fifties Triumph T100
Joined: Aug 2007
Posts: 290
S
SteveM Offline OP
Britbike forum member
OP Offline
Britbike forum member
S
Joined: Aug 2007
Posts: 290
First thanks to all for the info. I should have mentioned that this is not an old bike. I'm building a Triton and may race it with AHRMA if it works out well. I'd like to beef up the old box to some extent where it makes sense and reduce as much lubricant leakage as possible.



Moderated by  John Healy 

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