Steering head on early frame

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Can anybody give some advice on how the steering-stop lugs work on the earlier Commandos with the triple clamps where the stem is attached to the bottom clamp. I have a collection of parts bought as a basket case the frame (1969 model with centre stand on frame bracket) has 2 steering lugs welded to the steering head at the bottom, but there does not seem to be any corresponding pin or other stop on the bottom clamp. I am quite sure that the bottom clamp is correct for an early Commando as it has the two studs at the front for mounting the S type headlamp ring. Am I missing an additional component? Also with these earlier type clamps do people generally convert to the later type bearing arrangement with a spacer added, or convert to taper roller bearings?
Many thanks

Dave
 

L.A.B.

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dave M said:
I am quite sure that the bottom clamp is correct for an early Commando as it has the two studs at the front for mounting the S type headlamp ring.

Do you mean the two studs that I think also act as fork leg pinch bolts? As that is where various photos show that the 'S' mounting ring lower brackets should fit?

Could these yokes possibly be late Dominator/Atlas/Mercury parts?

Do you have any photos of these parts?
 
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L.A.B., Those studs I am refering to are indeed the lower clamp pinch studs. On the earlier Nortons including Commandos they screw in from the rear and the forks are tightened by a nut (5/16") that goes on them also from the rear. The S type and early Roadster have a stepped stud with a 1/4" dia threaded protrusion that stands proud at the front of the clamp onto which the headlight ring bracket mounts. The clamp itself is still tightened by the 5/16" nuts on the rear. The clamp I have has the S type studs fitted and this is why I assumed it was an S type lower clamp. My confusion is caused by the fact that there seems to be no provision for this lower clamp to but against the frame stops on the steering head on full lock. I do note from a glance at Bacon's book 'Norton Twins Restoration' (page 142) that the earliest frame illustrated here has a plate below the tank/coil mount that would act as a steering stop for the clamp that I have, but the slightly newer frame pictured above has the two lugs welded at the bottom of the steering head equidistant from an imagined centre line. This is the frame that I have and I need to know how the steering stops work with the lower clamp. It may well be that I have an earlier clamp, in which case I may have to either modify this with the fitting of some kind of peg, but I am confused about the studs which are definitely from the later model.
As you well know I am technically inept in the computer department so you might have to pop over with your digital camera and help me out yet again! I may have to wait until my next trip abroad to have a look at a similar model unless some kind soul has a bike of the right age and a digital camera.
Thanks
Dave
 
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Dave, I have a 70 and 'me bud' has a 68/69 fastback.. I will take some closeups this weekend and post them for you.. Cheers Chris

obtw, the 70 R's came with the halo headlight as well as the 'S' model..
I was real excited when i picked Herb up thinken it was an "S" but no..
numbers don't lie.... :cry:
 
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Chris, A photo of the lower clamp would be a real help. I am building an S type replica and have most of the parts to complete the project. I am at the moment repairing a rather badly bodged frame including a shortened rear loop, extra brackets welded in various places and a damaged rear shock mounting and I want to make sure that the steering head is OK before sending the frame away for painting.

Additionally what kind of steering head bearings are you running in your 1970 model?

Thanks very much
Dave
 
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dave M said:
A photo of the lower clamp would be a real help. I am building an S type replica and have most of the parts to complete the project.

Here are some pics from my early '70 Roadster. In the bottom one, you can just see the little tabs on the steering neck that act as stops.

Steering head on early frame



Steering head on early frame
 
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Rightshift, Thank you very much for the clear and detailed photos. L.A.B. and Captain have also been very helpful in this regard kindly sending me photos by e-mail. This is indeed the same as what I have and it looks to me that the body of the bottom clamp simply bangs into these two tabs on full lock, which must play havoc with newly painted clamps.

The second part of my original question was whether owners of these earlier models upgrade to taper roller bearings in the headstock or the later type commando rollers and if so presumeably there is some machining needed on the bearing udjuster nut under the top clamp?

Dave M
 
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Dave, my friendly mapcycle.com catalog only reflects one type of sealed bearing for commandos 37-7041 page 73 of their book.. hope this helps!
 
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Captain,
The early type clamps have an adjuster nut under the top clamp, presumably this is for adjusting ball type races, however if I fit the later type sealed bearings and spacer tube I suspect that I may have to modify the adjuster nut by machining the bottom collar off altogether so that the nut can fit flush against the bearing and thus not affect the distance between the top and bottom clamp.
 
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I have just checked and the adjusting nut collar fits nicely inside the sealed bearing so no machining is necessary although i will have to obtain or machine up another distance tube to go between the two bearings.
 
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Further to my earlier comments regarding bearing spacing, For everyone's future reference, I have found that the head stock inner on the earlier and later frames has a different distance between bearing seats when using sealed bearings and necessitates an additional bearing tube-spacer of approx 6 mm to be added when converting to the later type bearing fitment.
 
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