Gearbox for a Norton 850 Mark2a

[Sniper]

Hey guys

One of my friends old Nortons decided do do the bearing in the gearbox on the way back from a rally up north and after taking it off, found out that it was truely F**cked.

I know these gearboxes are about as hard to find as a virgin in vietnam at the moment, but would any one know anyone who might have one lying around for a good price. My mate is a bit slow and doesnt think its worth his effort to fix the bike, but I love it and I would like to see this classic still cruising the road. So I will fix it if nessesary.

Cheers :ride:

[Blakamin]

My mate is a bit slow and doesnt think its worth his effort to fix the bike,

Cheers :ride:
HOLY SHITE!... I aint never heard that from a norton owner... they normally go out and get shit made!
I'd suggest these guys... http://www.britishspares.com/ in Upper Hutt direction

[Motu]

The Norton or AMC gearbox was the strongest gearbox to come out of Britain,those things have been used in every special built,twin engined supercharged dragsters,behind Vincents,car engines,you name it - they are as tough as you can get.How the hell did he destroy it completely? It should be rebuildable,but you'd have to find someone who knew about them and could get parts - the bearings are standard items,but bushes will need to be made,gears and shafts purchased or made...nothing is irapearable.

[Paul in NZ]

The Norton or AMC gearbox was the strongest gearbox to come out of Britain,those things have been used in every special built,twin engined supercharged dragsters,behind Vincents,car engines,you name it - they are as tough as you can get.How the hell did he destroy it completely? It should be rebuildable,but you'd have to find someone who knew about them and could bet parts - the bearings are standard items,but bushes will need to be made,gears and shafts purchased or made...nothing is irapearable.

Yeah they are tough BUT when used in Commandos they have a nasty habit of cracking the main bearing housing pretty well rooting them.

Buy an issue of Classic Bike and look for an add by Mick Hemmings, Norvil etc etc and I'm pretty sure an upgraded g/box housing can be bought.

If your mate truely does not want it. Let me know because I bloody do!

Paul N

ps If you get stuck give me hoy. In addition to BMS in welliewood, try Best of British in ChCh. Tell Les / Alan I told you to call and they will only double the price!

[TwoSeven]

Yes thos commandos are brilliant machines (well they are one of my favorite bikes). Kick the begger if he doesnt get it running again. Otherwise it looks like another candidate for the triton club.

[Paul in NZ]

Yes thos commandos are brilliant machines (well they are one of my favorite bikes). Kick the begger if he doesnt get it running again. Otherwise it looks like another candidate for the triton club.

Oh please please! Would you stop making an utter prat of yourself. I'm not sure I can take much more laughter....

Tritons were/are traditionally made from Norton Featherbed frames (real or replica). IE Manx's/Dominators, NOT Commandos... They are utterly different!

Or perhaps you would like to show me a stunning Triton (Norton frame, Triumph engine) utilising an isolastic (ie rubber mounted) Command frame? Christ on a crutch, I can't even think why you would do that let alone how?

Have you even really seen a Commando? Or maybe you have been quoted out of context again?

Paul N

[Motu]

As a Triton owner in my younger days I had to bite my toungue on that one Paul.A Commando is a completly different bike than the featherbeds,much more lively in the handling,but nothing beats the on rails feeling of a featherbed on a rough corner.I've had wideline and slimline featherbeds,the Triton was a wideline.A Commando motor can't be used in a featherbed,you need the Atlas crank for that - as for putting another sort of motor in a Commando frame? well I've never heard of anyone doing such a stupid thing.

[Paul in NZ]

As a Triton owner in my younger days I had to bite my toungue on that one Paul.A Commando is a completly different bike than the featherbeds,much more lively in the handling,but nothing beats the on rails feeling of a featherbed on a rough corner.I've had wideline and slimline featherbeds,the Triton was a wideline.A Commando motor can't be used in a featherbed,you need the Atlas crank for that - as for putting another sort of motor in a Commando frame? well I've never heard of anyone doing such a stupid thing.

Well putting on my 'Train Spotter' Anorak Motu...

It's actually pretty popular in the UK right now to stick Commando power units into Featherbed frames and Unity etc all offer conversion kits.

I agree totally about the handling diff between the featherbeds and the commando (still a nice bike) but it was not a patch on a good featherbed in the twisties. On the motorway I'll take a decent commando...

The original Tritons date earlier than the classic 60's rocker days. (remember in the early 50's Nortons featherbeds frames were made by the McCandless bros - the designers- and they were seriously in short supply)

In the 50's the 500cc Formula Junior (or FIII) was a very popular way to get into motor racing cheaply. John Cooper's little cars were one of the best and gave him the start he needed to give us the Mini Cooper we wanted. Anyway. The Manx Norton was the motor to have but Norton Motors being the cunning beggars they were would not sell just the motors, you had to by a whole bike and thus there were a lot of very good chassis about with no motor. Triumph on the other hand had made the T110 and the T100 (C kitted or with the Delta head) which was one of the best engines of the era but the pre unit chassis was not! (it can be but needs a lot of up keep to stay that way)

The non factory supported racer lads bought these cheap chassis and slotted in Triumph Twin engines and started winning races culminating in Dave Degens classic win in the Barcelona 24 hour race (not bad for a home made bike).

The average performance rider of the time being a fashion victim even then, wanted the same 'look' on the street and soon poor old 350cc Norton singles were being plundered for their frames to the extent they are really rare now.

Dave Degens was asked to make so many he gave up racing and Dresda Motors is still making them today!

So really. The classic Triton has a pukka Manx frame (brazed reynold 531 tubing and rather more special than the ones we mere mortals got) with all the fruit from the Manx.. (easy way to spot a manx frame is wide radius of the top rear bend on the frame, no gusset at the steering head and oval tube swing arm.

(I never found any diff handling wise between the wide/slim version of the street frame but the slime line was a lot easier to ride on the street.)

Unfortunately. NVT experimented with a lot of different motors in the Commando frame. (250 and 500cc unit BSA singles being the most absurd) just as Triumph used the Norton isolastics in the T140 AV (anti vibration) to try for a tilt at the police bike market. Made 14 or something.

Paul N

[Motu]

Norton frames minus engines? - One day I was walking around with Len Perry in the canyons of his outside storage area...even the mechanics worked outside under leantoos,didn't worry rough necks like Dave Tompkins,but some of the young guys moaned,didn't move Len none.Anyway we were wandering along with Len pointing out things of interest....''here's what you want young fulla,a brand new featherbed,never been used that one'' there was a featherbed sitting on the ground,grey frame,no forks.'It's got no forks,I'd haveta find some roadholders and some sort of rear wheel' ...''well you won't find any brand new wide line featherbeds now,you can have that one for $75''....'What else ya got?'

Mate of mine has a Triton,real old,grey frame with bolt on rear section (Manx) it has the old pre AMC gearbox and an Alky burning T'Bird in it,it used to have a speedway sidecar,so has some weird fork geometry.We used to get tanked up on port (see my wine thread) and get his old race bikes going and blast them around the streets - geezuz wept mate,if it's not the fastest bike I've ridden,at least it's the scariest!

[TwoSeven]

Anyhow - the point of my post is that commandos are nice bikes and it would be a shame to see one go to waste or get butchered by turning it into something else.

[Sniper]

Thats true, they are great bikes, but Im still finding it hard to find a gearbox for the norton. Any ideas guys?

Cheers

[Paul in NZ]

Anyhow - the point of my post is that commandos are nice bikes and it would be a shame to see one go to waste or get butchered by turning it into something else.

Thats odd since you're the only one suggesting it

[Paul in NZ]

Thats true, they are great bikes, but Im still finding it hard to find a gearbox for the norton. Any ideas guys?

Cheers

Have you tried what i suggested and buy a copy of Classic Bike?

I can look through an old one if you like? Give you the web addy of some pommy places as there is a good chance you don't need a whole box.

Paul N

[Paul in NZ]

Norton frames minus engines? - One day I was walking around with Len Perry in the canyons of his outside storage area...even the mechanics worked outside under leantoos,didn't worry rough necks like Dave Tompkins,but some of the young guys moaned,didn't move Len none.Anyway we were wandering along with Len pointing out things of interest....''here's what you want young fulla,a brand new featherbed,never been used that one'' there was a featherbed sitting on the ground,grey frame,no forks.'It's got no forks,I'd haveta find some roadholders and some sort of rear wheel' ...''well you won't find any brand new wide line featherbeds now,you can have that one for $75''....'What else ya got?'

Mate of mine has a Triton,real old,grey frame with bolt on rear section (Manx) it has the old pre AMC gearbox and an Alky burning T'Bird in it,it used to have a speedway sidecar,so has some weird fork geometry.We used to get tanked up on port (see my wine thread) and get his old race bikes going and blast them around the streets - geezuz wept mate,if it's not the fastest bike I've ridden,at least it's the scariest!

What rips me is that I had a spare slimline chassis with forks, wheels, clip ons and fibre glass lowboy manx tank that I bought for $110 'cos it had a good standard tank for my Atlas... I kept it to build a racer for 2 years but when I went to England i had a clear out and... (sigh)

Paul N

[Sniper]

Have you tried what i suggested and buy a copy of Classic Bike?



Yea I have thanks, I havent found his add yet but Im still looking, I have a couple of friends who have the old classic bikes and they are scanning their eyes over them too.

Thanks for the advise tho, its a life saver :2thumbsup

Stu

[Paul in NZ]

Yea I have thanks, I havent found his add yet but Im still looking, I have a couple of friends who have the old classic bikes and they are scanning their eyes over them too.

Thanks for the advise tho, its a life saver :2thumbsup

Stu

Stu

Drop me an email tonight. I'm sure there was a write up about improving commandos a while back and I have it some place. It will be in there!

Link to owners club links page

http://www.ncno.org/links.html

http://www.domiracer.com/

http://www.fairsparesamerica.com/

http://www.norvilmotorcycle.co.uk/

Email them. This is not the first commando to shit it's gearbox! Norvil even do a rebuild kit!

[Sniper]

Hey paul, thanks you are a legend

Hey, one of my mates found a gearbox fopr it in CHCH, not too sure on if its the right type ect but I got it for next to nothing ($250)

So here comes the good part, putting it in.

Wish me luck :)

Sniper

[Paul in NZ]

Hold up there....

They are a good gear box but while it's out, do the poor old thing a favour and give it a fresh set of bearings and gaskets. A few hours work!

It will give you a chance to pull down the old box for a look see as well so you can check it's the same. I think there is a special tool required for the clutch on those things (single spring diapraghm)

They all look visibly similar and I'm a bit hazy on it but I think there are differences between Dominator one and Commando ones. Certainly the gear ratios will be different so resist mix and matching parts until you are sure.

Check the Norvil page and email them and ask if they can help identify it (the box) as being suitable. I'd certainly recommend their advice and their rebuild kit!

You got the box for stuff all and the bikes are worth a $$ or 2 so it pays to get it right!

Cheers

[Motu]

Also check and maybe replace that little shift lever return spring,not much money and it's kinda silly when the lever flops down and won't shift,you might burn out the clutch if it happens in top.

[Sniper]

Yea, that makes perfect sence. I wasnt too keen on just popping in back in the bike, I always like taking things apart. :)

I also might give Norvil a ring Dave, I mean, its worth spending a bit of $$ to get this right so I dont have to watch the old girl struggle with a bung artifical leg (Gearbox) again. I recon its worth it.

Motu, I might also check that out if Norvil doesnt send that part in the rebuild kit.

Thanks guys

[Paul in NZ]

I did some digging...

It's usually the layshaft pinion that strips it's teeth due to the mainshaft flexing under load. (the commando make lots of torque) There is a layshaft roller bearing conversion kit available that strengthens it up. Recommended!

Check you have not got an old dommie box as it won't last unless it is strengthened.

Paul N