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  1. #1

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    Default 71 Norton Commando Steering stem size

    Can anyone tell me what diameter the steering stem is on a 71 Commando? And are they straight or have some kind of taper?

    Thanks

  2. #2
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    You looking to swap bearings or what?

    look here:
    Steering Head Bearings
    A discussion on steering head bearings and the use of tapered roller types
    The Commando headstock bearing is a standard sealed ball race type 6205-2RS, which measures
    25 x 52 x 15mm. The taper roller equivalent is the type 30205...
    https://www.nortonownersclub.org/sup...-head-bearings

    looks like she is trying to get a closer look at the stem size:
    Click image for larger version. 

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    Last edited by TriNortchopz; 08-06-2019 at 9:42 PM. Reason: inspector

  3. #3
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    The correct answer is: "It depends" Off the top of my head I generally say approx 1" inch, & TNC is mostly correct in that most 1971 C-Dos have a sealed bearing top and bottom.
    But in all things Norton there is variables, Not enough info here to answer properly. Are you trying to use Norton trees/forks in a Norton or something else? Are you SURE you are working with 71 Commando parts?

    So the stems and trees varied across many Norton models in many ways, Steering stops, lock location, Handle bar mounts, tabs, WIDTH of the trees and resulting axle widths as well, and most importantly rake.

    So the basics is, most commandos did use a straight shaft stem but 750 stems and trees were straight to the forks when viewed from the side. 850s (73 on and Mk1, Mk2 & Mk3) had raked trees.
    ** Many Norton people and tech warns of extreme danger to life and limb if you mix tops and bottoms or frame types 850 vs 750 with the wrong trees as its allegedly dangerous.
    My personal experience is, not really, and several other say so as well, but it might be true. We have a young guy who keeps crashing in our Norton club and some think there is a frame or steering issue. I cant say but in general you should pay close attention to what parts you are using.

    Now, Norton-Matchless hybrids and pre-Commando models (ES2, N15, P11, Atlas, Domminator and others) also had some variables, the stems are smaller and several variations in trees, widths and steering stops and most of these used taper bearing races and the little balls. Some convert to a auto type taper roller, Some convert to C-Do style straight sealed bearings.

    I have more trees and currently sorting Norton parts in old shop inventory, But I found some variables in stem Dia. In Commando type from 0.9865" OD of the stems to 1.1285", Pre Commando I found most at .8195 and 2 dia stems but the mid point is that measurement, races were larger,, but found some others at .8095" and thats just sampling a few.

    Here is a pix for reference: Click image for larger version. 

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  4. #4

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    Here is where I am at... I’ve got a 71 750 frame and rear swing arm. I am toying with the idea of installing a set of GSXR 600 fork tubes on a custom triple tree to accommodate the larger fork tubes. So I am still in 10k ft view territory in AutoCad playing with it before dispatching to the machinist (my brother) to mock up.

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    Well, I have a variety of Nortons and years from my old shop I am working on after being inactive, And keeping in mind digital calipers are useful, I would not rely on them to print for manufacture. But trying 3 different C-Do frames with used sealed bearings in them I found . 9650 to .9800 ID on the Bearings.

    However, See this site for illustrated diagrams from the parts books. https://andover-norton.co.uk/en/shop...strument-cases

    If you look, there was a lot of changes. Atlas up to 68, then 68-69 Commando. 1970, then 71-3, then 73 and up all had differences.At some point the stem got attached to the top tree instead of the bottoms.

    However your idea is valid.(Repurposing modern forks) Ive been involved in Nortons over 30 years and seen many variations of what you are doing. Custom made billet trees, as well as different/modern forks. I know Kenny Dreer well, ( Vintage rebuilders & Norton America) And was involved in all that. He and his shop guys did a lot of innovative stuff. One of the early mods was using modern fork internals inside Commando legs with adjustable preloads. Cosentino engineering is currently offering a version of that for big $$$$$ Then they went all modern Forks and trees on the Commando frames before going to a new clean sheet design and reviving the Norton brand. (Financier pulled the plug and sold Norton back to the Britts. I own what remains of Norton America.)

    So, I have a project sitting aside where I have most of a Kawasaki Ninja and intending to graft a lot of that onto the vintage Norton, But its challenging. It can be done.

    You do of course need to check your math on rake and trail and be aware as mentioned that early Commandos had rather quick steering. The reason for raking the trees was to make it a bit more docile for touring. There might be a change in swing arm and wheel base as well but I dont recall (73-on 850s)

    One thing you HAVE to understand. The Commando frame is as my friend Hobot says.. "A flexy-twisty rubber baby buggy bumper flyer" Which means they are very light and flimsy. Its structure comes from everything being in synch and totally rubber mounted frame/motor/trans/swingarm. If you bump a curb hard chances are you tweaked the frame. Its rare to find a totally straight used frame. So when I started collecting parts for my morphodite several friend said as soon as I plant the brakes the frame will fold in half. They are not half wrong.

    You might also want to download this and read it.. See: https://nortonclub.com/docs/Straight...ando_Frame.pdf
    Bike Exif and other sites feature some pretty custom Nortons, Besides the obvious CNW builds. See:

    http://www.bikeexif.com/norton-comma...28Bike+EXIF%29

    Click image for larger version. 

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    I am toying with the idea of installing a set of GSXR 600 fork tubes on a custom triple tree to accommodate the larger fork tubes.
    Since you are doing that, the original Norton neck post is not much of a factor - just need one to fit the bearings you will be using (with 52mm OD race to fit frame neck), your machinist bro can whip up one of them too.

    These guys custom build trees and neck posts to provide a complete kit for fork swaps, with four options for offset; one kit is for GSX-R forks on a Norton ($800 US.):

    https://cognitomoto.com/products/cus...rk-to-any-bike


    Here is a link to a Workshop Series; this one is installing a Cognito kit GSX-R forks on an old Honda, but process is the same:
    Click image for larger version. 

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    https://www.returnofthecaferacers.co...rk-conversion/

    Some discussion here for the swap:
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    "...ZX6 & ZX9 required very little modification to the yoke stem...used standard Norton steering bearings"
    2015 Thread: USD forks:
    https://www.accessnorton.com/NortonC...d-forks.19077/
    Last edited by TriNortchopz; 08-07-2019 at 11:51 PM. Reason: access site

  7. #7
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    Quote Originally Posted by TriNortchopz View Post
    Since you are doing that, the original Norton neck post is not much of a factor - just need one to fit the bearings you will be using (with 52mm OD race to fit frame neck), your machinist bro can whip up one of them too.


    Some discussion here for the swap:

    "...ZX6 & ZX9 required very little modification to the yoke stem...used standard Norton steering bearings"
    2015 Thread: USD forks:
    https://www.accessnorton.com/NortonC...d-forks.19077/
    ---------------------------------------------------------------------------
    Yes, that is a useful thread and discussion, Those guys have a lot of experience. The long distance tourer with the luggage is Jim Comstock in Colorado, And he covers vast territory and attends most every INOA Norton rally that I am aware of. (As in cross country rides) He also used to race.
    The other wanker is Grand Paul, as with all Norton owners, somewhat weird but very enthusiastic.

    So Paul was infatuated with building a one off of what Dreer was building prior to the new Norton America bikes. This was the Vintage Rebuilder VR880 series bikes of which I have all the build files on each bike. *** IF someone with a VR bike want info on theirs, Contact me, or if you want to verify one before purchase.

    So the VRs were optimized Nortons, most of the bugs worked out and modernized and mostly new parts as vintage Nortons had quality control issues. Kenny was moving to all new frames, engine castings, trans castings, electric start, modern electronics, ignition, fuel system etc. Basically a night and day difference between a stock Norton and his. A sore subject is modern day Colorado Norton Works-CNW Bespoke builds as basically Matt is replicating the VR Nortons.

    However, Props to Matt @ CNW and he does a nice job and quality builds if you (ahem....cough cough) can afford his price tags.

    So, I also did a series of tech and interviews with Kenny and filled in the blanks, there was a lot of interim stuff as well as early versions of the Norton America bikes,,,Click image for larger version. 

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    Now the frames were all new, and beefier (Built and designed by C&J racing frames) and the business plan was to offer a variety of wheels, forks and suspension. USD and regular forks, Spoke and mag wheels including a carbon fiber version. OHLINS wanted in to be sole supplier for shocks and forks and the forks you see above? There is only 4 pairs of them in the US, They were designed for a race series in Asia that never took off, but there was a deal in place to offer them on the new bikes. I own this bike now, and yes,, people drool over them. (Had many offers to sell)
    However there was some USD forks too. Some of the prototypes used the same mag wheels as the Buell XBs but there was some Italian wheels on the table. (I have a prototype of one of those as well)

    There was a prototype built using a Monoshock, It did not test well with the public, So the idea was dropped but a version debuted at Laguna Seca at the product launch. (I posted some of this on the Buell forum as well) Heres the kinda chicks you can get if you ride a cool Norton. Click image for larger version. 

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    ** Trivia tip, Among the merch on sale was ladies thongs in plaid with a Norton logo, these sold out the fastest and I can confirm these ladies are wearing them. (Ponder that)

    So here is a set of the custom Triples to run marzocchi forks and later some Ohlins, I have a few of these left, (No not for sale) But gives an idea of the ideal layout you should shoot for. As mentioned in the In-Accessible Norton link, The layout of the trees can be a problem if not done right,, Modern Sport bikes have little offset, these vintage designs need more and again PAY ATTENTION to rake & Trail. Jims comment is 100% correct as well, Raising the ass end of the bike will change your handling and dropping the front and raising the tail goes way back in setting up race bikes.

    (* I have a Bud Ekins article on setting up off road and road race frames with modified BSA triple trees and dropping the front and longer rear shocks done around 1962-3)

    ** So the pix of Pauls Monoshock bike is NOT a true VR880 although he built it using parts purchased from Vintage Rebuilders/Dreer. Its a cool bike and well done, But its a replica/tribute, not the real deal. I have the makings of 2 more VR bikes myself since I bought out Kennys shop, But mine are not real VRs either. although I have the company docs to make it look like that including a stack of MSOs

    Click image for larger version. 

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    Now, what Stuart Garner and the current UK Norton company is building, Is pretty cool and I have a relationship with them and it mandates I promote them in a positive way, But I had my doubts at first but I am a big supporter and they are doing fantastic things, So check out their website, and some of the cool bikes they are building. IMHO the baddest bike out there is their Domminator built using a modern Featherbed type frame, check out the forks and trees on that bad boy!

    Click image for larger version. 

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