dating a mongrel

Hello Forum. hope you are all well.
I have a Fastback that I have owned since 1976. The bike has always been a bit of a mongrel regarding originality. When I got it it had a disc brake fitted. central oil tank and no side covers at all, and 2 into 1 exhaust.. When i got this it had the late type steering head with the disc brake. I rode this for quite a while and had no handling issues, contrary to advice not to mix fork yokes and frames.

The engine has the points behind the engine where the magneto mounts, and tacho drive off the camshaft.

To me the disc were not introduced until 1972. On the ID plate there is a frame number but no month of manufacture stamped on it. The frame appears to be pre 72 as it has the centre stand mounting on a tube welded across the frame under the gearbox cradle. The stand did not mount on the cradle.

Over the years I have slowly been returning it to what I think it should be, re drum brake, oil tank on the right hand side, early Atlas style steering head etc. It will never be an original factory bike again but the bike being 42 years old it does not matter to me what the purists may criticise.

I have searched this forum for info but cant find what I am after. I have been told by various knowledgeable persons that my frame is September 1970 and engine is late 1969 but the advice has varied a fair bit on the dates..

The frame number is 139206, engine number 20M3130517.

Can someone help me here by identifying exactly the dates of engine and frame. This has been bugging me for a while and I hope someone can put me right here and tell me exactly what I have got..

Best wishes to all and thanks in advance for any advice.
Bradley

I used to date a mongrel,
but.........Not only was she Ugly - She was CRAZY too!
I had to dump her before flipped out and tried to kill me.

Brandon:

I hope you put the stiffener kit into that awful Campagnolo 2LS front brake. I wouldn't dare ride in modern traffic without it. I was given the job of discovering why the original brake was so poor. I concluded fairly quickly that being able to pull the brake lever all the way to the twist-grip with no additional braking action ndicated a stiffness issue.

Testing with a spray-on clear paint called "brittle lacquer", which had no elasticity, allowed me to find how the back-plate was distorting under load. By the time it got fixed, the Commando was a production machine and all development effort was done at the Plumstead factory. My group at Wolverhampton weren't involved.

The other caution I have is, please make sure you get the additional tube installed in parallel with the main top tube of the frame. We didn't do enough hard miles of testing before the original frame went into production to discover the weakness. I was amazed when I saw a photo of the failure on this group a couple of years ago.

In the AJS Stormer M-X program, we had a frame design very similar to the Commando, except the top tube was welded to the bottom of the headstock instead of the top, and the wrap-over stiffener was above on the AJS rather than below as on the Commando. The Stormer frame failed repeatedly in our works M-X program, and it looked just like an upside-down repeat of the Commando cracking. Using the same brittle lacquer, I managed to show that the wrap-over stiffener was causing a stress raiser at the aft end, where the crack was appearing.

At one meeting, we offered Dave Bickers a ride on our bike during pratice and he came back full of praise for its handling.

We discovered when we got home that the frame had completely failed through the top tube and the frame was being held together by the fuel tank. N-V fixed it with a design I came up with. I took the main tube and split it horizontally along the centerline. At the headstock, we opened it up to cover about 90% of the headstock depth. At the seat end, we left it in its original circular shape We then welded in a long triangular piece to fill the gap. As far as I know, the KTM version of the bike still has that top tube design. It would look a lot neater on the Commando than that extra tube lash-up the factory came up with.

Bradley,

Sounds like you have bits of early bike parts. My 69 'S' is serial 132031 date stamp APR 69 on the ID plate. Frame, gearbox and engine matching. 139206 frame number would put it between June 70 (135088, the last 'S') and Jan 71 (141717, the last Fastback MK II). I doubt if your frame doesn't have the lower brace tube in it.

Engine 130517 is a very early number, between the first production number of 126125 and the first Fastback (131180, Mar 69) and would have the tach off the R/S cam cover and the points in the top rear of the timing cover, like you mention.

The central oil tank is a question mark, as it really was only used in the 'S', 'R', and 70 Roadster models.

It sounds to me like someone put together a very early bike with very early parts from different years.

The front brake can be made to work acceptably, even without the stiffening plate, for casual riding, the shoes just need to be arced to match the drum. If you need more braking, the stiffening plate will help.

Let me know if I can help with any other information. I have a very long thread on the restoration of my 69, search for '69 Phoenix rises'. You may find some interesting info there on pre 71 bikes, but it's a long read.

Frank Damp,
You may be surprised at how good the front drum can be made to work for casual riding, not racing or track work. I find it completely acceptable now that I know what I'm doing without the stiffening plate, which is rather expensive.

Dave
69S

Frank and Dave

Thanks for that.

I guess I have never rode hard enough to have any trouble with the drum brake. Mainly rural Australia, decidly lack of heavy traffic there. I still have all the disc gear if I ever want to change it back . Dave, I will go and have a squiz at your Phoenix thread, should be interesting.
Thanks again
Bradley

Mongrel women rock. Beenthru 3 of e' m. Herlped a brother re-start up a 74 828 tonight. Steamwhistle beers. India.

Oh yeah, Caswell linered tank ,steel , Boyer Mk 111 ign., single Mikuni,new seat,new Konis,Needs help... We got her going thanks to quick start spray, sitting too long ,4000 dollars cheap.

Mark said:

I used to date a mongrel,
but.........Not only was she Ugly - She was CRAZY too!
I had to dump her before flipped out and tried to kill me.

Click to expand...

Except for the "ugly" part, you have just described the quintessential Norton.

B.Rad,

my frame no 139362 - within 156 of yours - is date stamped June 1970, so it is possible (I am tempted to say probable, but I understand that there was some leeway in these things; there are people on this site with greater and possibly even first hand knowledge of these things) that your frame was made in May or June 1970.

Frank Damp has referred to the need to strengthen the frame on some bikes; and I understand that the factory did replace some of the early frames which were susceptable to failure. I wonder if this bike was one of those? Again, some people on this site will have that information close to hand. That is an easy explanation for the non matching engine and frame (another being a big crash and new frame and forks some time before you bought it).

G'day Bradley.
As Dave said, you've got a real bitsa of an early bike there. I think Norvil's website also has listings on numbers vs dates and configurations.
And also as Dave said, I believe the drum brake in standard form can be fine for casual riding. All I did when I restored my bike was fit new shoes and it seemed ok.
At the time I was blissfully unaware of distortion in these brakes - I only learned of it recently by perusing Norvil's parts lists - or even the need to to arc the shoes.
In comparison with my previous bike, a 72 disc-braked Fastback, the drum brake seemed surprisingly good.
However, when the PO, a friend of mine, had my current bike, we swapped bikes for a day and I noticed then that the front brake worked very poorly. Actually it didn't work at all,and yet he still rode it. My bike at the time was a Honda CB175.
Shortly afterwards he fitted a disc brake front end to it, and a bit later he collided with a car. That was the end of the disc brake setup, and the bike's mobile days until I bought it.
Bent frame, broken crankcases and barrel, but mostly all there. August 1983.



The bike was originally a Roadster, but I wasn't struck on the capacity or even the looks of the Roadster tank, and so some mongrelisation ensued.
Fastback tank, home-made seat and side covers. The colour is Deep Aqua, as seen on Ford Falcons in the 70s. June 2006.



I don't mind it being a mongrel. It nearly died once, and so did Gary.

Cheers
Martin

B.Rad said:

I have searched this forum for info but cant find what I am after. I have been told by various knowledgeable persons that my frame is September 1970 and engine is late 1969 but the advice has varied a fair bit on the dates..

The frame number is 139206, engine number 20M3130517.
Can someone help me here by identifying exactly the dates of engine and frame. This has been bugging me for a while and I hope someone can put me right here and tell me exactly what I have got..

Click to expand...

The only people who can tell you that with any accuracy will be the records section of the VMCC or UK NOC as they both have access to the surviving Norton factory records for that period.

http://www.vmcc.net/library.htm
http://www.nortonownersclub.org/records-dating

Hello again all.

I would like to thank all who provided advice about my numbers. It is really humbling to have people from all over the world give freely their advice without hesitation.

It just re-inforces the spirit of co-operation that seems so missing in this modern world. This is really a unique forum.

Thank you again and best wishes
Bradley

was just reading this and noticed Dave said "first Fastback (131180, Mar 69)" My bike is # 128287 matching frame and engine. The book i looked at shows production b/w march and sept '68. Fast back as previously talked about. So.....is it possible this bike didnt come as a fastback originally?

usefulidiot said:

was just reading this and noticed Dave said "first Fastback (131180, Mar 69)" My bike is # 128287 matching frame and engine. The book i looked at shows production b/w march and sept '68. Fast back as previously talked about. So.....is it possible this bike didnt come as a fastback originally?

Click to expand...

Originally, the "Fastback" model was simply known as: "Commando".

The name Fastback was only officially adopted when other Commando models (S & R types) were added to the range.

Whoops. That's my mistake. I should have said 131180 Fastback (not first, maybe name only). I'm pretty sure the first production machine (Feb 68) was a FB, they just didn't call it that until maybe Mar of 69 when they decided to come out with the S, R and Roadsters and started using camshaft points. So I think you're OK as a FB there, it just probably wasn't called that when it was sold, just 'Commando'.

Just to re-iterate what Les says.

Dave
69S

cool, thanks for the clarification

Ditto. The original and the best looking Commando, IMHO. Although I prefer the upswept pipes of the later models.
Martin.

Hello Forum. Hope u r all well.
Regarding my enquiry regarding dating and engine numbers. My thanks for all replys, very much appreciated. the help and advice here is unbelieveable.

I have had contact from a bloke that has a 1970 Roadster that is within 30 numbers of mine. This bike has full history since it was purchased by the owner new..

The amazing thing is here are 2 Nortons within 30 numbers being sold in the same town in Queensland in 1970. His bike is stamped June 1970, a Roadster with the halo round the headlight and upswept peashooters..

So I reckon June 1970 will be close enough for me.

As to my bike being a Fastback originally, I dont know and wont worry too much about it. It is a fastback now.
I really like the photo from "uesfulidiot", too me it is the prettiest Commando ever , I like the 2 tone color.

Thanks again to everyone
Best wishes
Bradley