• Welcome to the forum website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Online Forum Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this forum website.

    If you have previously registered to use this forum website, you should log in now. CLICK HERE.

    If you have never registered to use this forum website before, please CLICK HERE.

Comet Ignition

cinquecento

Well Known and Active Forum Website User
Non-VOC Member
Having prob's uploading photo's so sorry for sketchy description.

Having received rebuilt mag' I went to take off timing cover for access to put on timing disc. during removal a 1" OD ali' spacer that i had not noticed fell of back of loose ATD that had been left in place in cover.


I can't see mention of a spacer between mag' and ATD in drawings and can't understand why one should be necessaary as the ATD is a taper fit. Not had an opportunity to measure up spacing between componets but wondered if anyone had any thoughts?

Thanks
 

A_HRD

Well Known and Active Forum Website User
VOC Member
Strange! How thick is this 1" OD spacer? Was it being used previously to wedge open the ATD ears to full advance while timing? Or could it have fallen in through the mag orifice while you had the mag off for rebuild? Or is it the alloy ring on the back of the ATD that is supposed to be on there tight…?! (Actually its supposed to be steel one, punched locked in place; alloy is no good because of expansion. I'll try to add a photo…. Image.jpg.

Incidentally, the timing cover doesn't necessarily need to come off solely for fitting a timing disc; just remove the big-end quill.

Peter B
Bristol, UK.
 
Last edited:

chankly bore

Well Known and Active Forum Website User
Non-VOC Member
We have had a case over here in Victoria where the taper had worn and allowed the A.T.D.boss to foul the timing chest. As stated above,there is no reason for an alloy spacer unless someone thought an oil spinner might be a good idea! Any extra weight on the magneto shaft should be avoided as the bearings already have a tough time with the whirring mass of inefficiency that is styled the Lucas A.T.D. If you want to see how it should have been made get a B.T.H. (original) one and compare.
 

cinquecento

Well Known and Active Forum Website User
Non-VOC Member
'scuse quality and inconsistancy of images.

don't have 'spacer' in front of me but i'd say it was approx' 1/4" thick. Peter B's description sounds closest but this alloy spacer was obviously not on tight. I can't see how a spacer fit's in with the taper fit as it would obviously either hinder the fit or just be spinning around serving no purpose on the end of the armature, or sitting on the back of the ATD.

In addition, the alloy spacer is slightly gnarley on the edges and I wouldn't want that butting up against the mag' oil seal.

I'll look at the set up again in consideration of the above comments and report back.

ps the timing chest cover came off as I was not familiar with the crank pinion dim's and how I would make a timing disc attachment fit.



bth_AAACometIgnition002.jpg



th_AAACometIgnition001.jpg
 

cinquecento

Well Known and Active Forum Website User
Non-VOC Member
All I can think is that a PO made up te spacer as possibly some way of retaining or slightly compressing the oil seal on the mag armature to aid sealing ?. Here you can see the spacer is a nice snug fit on the rear of the ATD so if it did bear or slightly compress the oil seal all it can have done was act as a wearing surface, curioser and curioser..
When I have the chance I'll try to measure everything up and see what effect this spacer was having.
th_AAACometIgnition004.jpg
 

A_HRD

Well Known and Active Forum Website User
VOC Member
I wonder if someone put that spacer in there because the nuts (which should be countersunk rivet-heads) were touching the back of the timing chest(?). Either way, IMHO it is a non-std lash-up and you should investigate closely with a view to leaving it out.

Peter B
Bristol, UK.
 

cinquecento

Well Known and Active Forum Website User
Non-VOC Member
I think you've got it there Peter B. Looking at your photo and comparing it to mine th change are mine has ATD and drive wheel assembly held together with nut and bolts (?) and an alloy coller/spacer/ring.

From your (standard?) set up it should be countersunk rivets and a peened on steel coller, therefore I can only guess mine has been dissassembled for some reson in the past, the steel coller was beyond salvage and replaced with an alloy coller and the rivets with nut/bolt setup.

I still dont see what purpose the coller serves but will clean it up and refit with loctite as it seems a good push fit. I don't seew why thermal expansion should be that big a concern. The rivets fitting into a fibre wheel I'm guessing will be alloy, steel obviously would need heating prior to peening over resulting in melted fibre wheel. If the current nut/bolt set up is not causing an issue other than negligable increase in mass and drag maybe I'll leave well alone.

Thanks for bouncing ideas around.

ps Oops! just noticed my set up also has that whole steel backing plate that the rivets are c/s into missing, deffo' goung to have to look into this further.
 
Last edited:
Warning! This thread is more than 9yrs ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.

Top