T120v Gearbox Parts

FrankC

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Hi all, I am new to this forum so forgive me if I get things wrong - for example I am in the UK and am not sure if anyone can advise over here or if most members are in the USA.

I am trying to source two cogs for my t120v gearbox. They are part number 574380 and part number 574392 - the cogs for first gear.

Does anyone know the best place to look as ebay can offer nothing in the UK and google has not helped much either.

All the best

Francis
 

Rocky

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We have many US members, but also many from the UK, Europe, Canada, Australia, you name it.

With so many spares dealers in the UK, I'm surprised you couldn't come up with something there.
I wish I could point you to a good source and I hope somebody jumps in who can.
 

grandpaul

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I must apologize for not remembering the names of the UK stockists, I used to know them from memory...
 

Rudie

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trying to source two cogs for my t120v gearbox. They are part number 574380 and part number 574392 - the cogs for first gear.
ebay can offer nothing in the UK and google has not helped much
They are parts from the early 5 speed, aka the "grenade" version ... :cool: You are looking because either you do not have the parts (because they broke and were thrown away) or you have the parts but they are broken? "They all do that, sir" ...

The 5 speed went through several iterations before the final version from 73; unfortunately, afaik the later corresponding parts - 57-4653 and 57-4654 - are not backwards compatible. Confirm with, for example, TMS?
 

FrankC

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They are parts from the early 5 speed, aka the "grenade" version ... :cool: You are looking because either you do not have the parts (because they broke and were thrown away) or you have the parts but they are broken? "They all do that, sir" ...

The 5 speed went through several iterations before the final version from 73; unfortunately, afaik the later corresponding parts - 57-4653 and 57-4654 - are not backwards compatible. Confirm with, for example, TMS?
Mine is a 1972, teeth shatterd off. I now realise that they are not backwards compatible - I found that out last night. It seems strange that I can't find anything other than a whole cluster for sale in the UK. Maybe this is a common fault and that is why these cogs are not easy to get hold of.
Thank you for your reply.
All the best
 

Rudie

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Mine is a 1972, teeth shatterd off.
It seems strange that I can't find anything other than a whole cluster for sale in the UK.
The whole clusters for sale are either new versions of the 73 on gearbox that have been made recently or earlier clusters that have been replaced because of their reputation. Afaik, a complete 73 on gearbox is a straight replacement for the earlier one in your bike, you can then use the bike with confidence, would be a positive selling point if/when you sold the bike. Cost about £500?

Or replace with a 4 speed gearbox? You could at least ride the bike, imho 5 speeds on 650's are overrated.

Maybe this is a common fault and that is why these cogs are not easy to get hold of.
No "Maybe" about it ... that is why I posted the possibly apocryphal "They all do that, sir" ... :cool:
 

FrankC

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The whole clusters for sale are either new versions of the 73 on gearbox that have been made recently or earlier clusters that have been replaced because of their reputation. Afaik, a complete 73 on gearbox is a straight replacement for the earlier one in your bike, you can then use the bike with confidence, would be a positive selling point if/when you sold the bike. Cost about £500?

Or replace with a 4 speed gearbox? You could at least ride the bike, imho 5 speeds on 650's are overrated.


No "Maybe" about it ... that is why I posted the possibly apocryphal "They all do that, sir" ... :cool:
fair point. is 'Afaik' and acronym or a manufacturer? excuse my ignorance.

I still need a supplier in the UK. maybe I will try searching for 'cluster' rather than the part number.

F
 

grandpaul

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I seem to recall that 1st and 5th on a 5-speed are the same ratios as on a 4-speed. So, the only benefit is the slightly better ratio span of the middle three gears in a 5-speed over only two in a 4-speed...
 

Rudie

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I seem to recall that 1st and 5th on a 5-speed are the same ratios as on a 4-speed.
Otoh, checking in parts and workshop manuals will reveal they are not ... :cool:

The top gear 1:1 ratio is the same in both gearboxes, as it is in almost every gearbox ... so there are no frictional losses in the gearbox when the vehicle is in top gear.

The parts manuals only give the teeth numbers of the 4 speed box ... but the 5 speed gears part numbers are all different, the T150 or 71/72 650 workshop manuals show all the gearbox ratios except top are different.

4 speed and 5 speed boxes are completely different. The 4 speed can trace its roots to something Edward Turner either designed for his first Speed Twin or inherited from the original Triumph company. BSA bought the 5 speed from Rod Quaife in late 1970, after it had been used in the 70 triple racers but the new 71 AMA Class C regs required at least 200 of any engine part to be raced to have been made available to Joe Public; BSA/Triumph believed it had to make at least 200 5 speed Tridents and 200 5 speed Rocket 3's; at the time, Quaife was a specialist racing gearbox maker, not geared up to make 400+ gearboxes in such a short period and commit to ongoing spares supply.
 

scottholl

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Hi all, I am new to this forum so forgive me if I get things wrong - for example I am in the UK and am not sure if anyone can advise over here or if most members are in the USA.

I am trying to source two cogs for my t120v gearbox. They are part number 574380 and part number 574392 - the cogs for first gear.

Does anyone know the best place to look as ebay can offer nothing in the UK and google has not helped much either.

All the best

Francis
Frank, I may have some of these parts. I recall that I sheared the mainshaft off on an aggressive downshift. My bike was a '72 Tiger (head swapped to make it a bonnie). I had to replace the entire transmission because even 35 years ago just a main shaft was not easy to come by. So if my memory serves me I kept the removed transmission so it is complete except no mainshaft! Now I need to spend a few days (at least) trying to relocate them in my parts spares. If I can locate them, what would you offer me for the whole transmission? Regards Scott
 

FrankC

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Frank, I may have some of these parts. I recall that I sheared the mainshaft off on an aggressive downshift. My bike was a '72 Tiger (head swapped to make it a bonnie). I had to replace the entire transmission because even 35 years ago just a main shaft was not easy to come by. So if my memory serves me I kept the removed transmission so it is complete except no mainshaft! Now I need to spend a few days (at least) trying to relocate them in my parts spares. If I can locate them, what would you offer me for the whole transmission? Regards Scott
That would sound interesting except for the fact you, I presume, are in the USA and I am in the UK. The postage time and cost of the whole cluster would be prohibitive.
If you find you have part no 57-4392 then we could consider getting just that cog in the post.

Check out if you have that cog and roughly how much it would cost to post. I will check how fast it would get here. Then we can see if it worth our while.

Thanks for getting back to me and all the best

f
 
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