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Fill in the gaps! 1954 Domi 88 bearings list

Submitted by bruce_kirby on Fri, 01/04/2016
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Heavy Twins

Hi All,

Possibly this has been done before, but I've been unable to find a suitable post here, so apologies if I'm beating the same old drum!

I compiled a small spreadsheet detailing the bearings required for my '54 Model 88, but can't seem to find references to which bearings go where. I'm looking for the commercial ID's for the bearings, not the Norvil (or whoever) part numbers. NJ306, or 6203 works for me, not 040100 etc. I need to know of these are RLS09 or whatever, and where they go.

Have a look at the attachment and if anyone can fill in the gaps, I would be most grateful.

As you will see, some I'm OK with, but there are gaps.

Cheers,

Bruce

Attachments domi-88-bearings-jpg

Submitted by bruce_kirby on Mon, 04/04/2016

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Sadly no response from the boffins yet.....

So some observations (relevant to laydown G/B and 1954 motor):

A2/321 x 2 occur in the G/B - what came out were a Hoffman LS7 (5/8X1-9/16X7/16", 15.875x39.688x11.113mm) and the other was an SKF 6203 (17mm x 40mm x 12mm). Curious.....

But more so is that the front and rear wheel bearings (A2/435 & A2/436) dimensions are:

  • A2/435 - 17mm x 40mm x 12mm
  • A2/436 - 17mm x 40mm x 16mm

So the A2/435 has the same dimensions as the gearbox bearing A2/321, detailed above, but a different part number.

What is it that I'm missing here? I just don't seem to be finding any absolute truth regarding bearing correctness! I reckon that I'll probably go for 6203's all round to replace A2/435 and A2/321.

Unless anyone can convince me that I'm wrong?

Submitted by stephen_mcdonnell on Thu, 14/04/2016

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Hi Bruce

I have recently been grappling with the same questions for my 55 Dominator.

You are right: the old parts list states A2/321 for both mainshaft RH and layshaft LH, but on disassembly I also found the same 2 different bearings as yourself. These are:

Mainshaft inner cover: 5/8" x 1/9/16" x 7/16". This is a LJ5/8 (RLS5).

Layshaft shell: 40 x 17 x 12mm. This is indeed a standard 6203. However, it seems to be generally recommended to use a roller bearing in this position. RGM sell the NJ203EM

Then the mainshaft (sleeve gear) shell is 1/1/4" x 2/1/2" x 5/8", which is a 1654. Ideally this should be a rubber shielded bearing (2RS - maybe best to then remove the inner rubber shield to let the gearbox oil into the bearing) to try to keep a little of the oil inside your laydown gearbox, but there is difficulty in finding this shielded version from one of the main bearing manufacturers, although you can find "budget" 2RS versions quite easily, but the quality concerns me. However, Japanese bearing manufacturer KYK do this as a 2RS, so I am hoping the quality should be ok. You can get it from Henderson Bearings on ebay.

Regarding the A2/435 wheel bearings, I am only guessing, but could it be that even back in the day Norton were fitting a roller version in the gearbox?

Hope this is useful

Stephen

Submitted by robert_tuck on Fri, 15/04/2016

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I fitted the roller bearing conversion to the layshaft in my 99. This left me with far too much end float which had to be shimmed out. I brought this up with Mr Hemmings and he does not recommend this bearing and the shimming but supplies a high spec ball one. I think (but dont KNOW) that the roller perhaps gives a different level of support to the shaft which can give other problems?. The 88 should not need the conversion. The specified ball race in the inner cover had to be releaved on its outer face to avoid the loss of running clearance once fitted.( this was after trying 2 new c3 bearings and cleaning out the cover carefully ,the 99 is a Bracebridge St build)

Submitted by bruce_kirby on Wed, 27/04/2016

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Gentlemen, thank you for your responses! At least now I have further opinions on the matter which takes the guesswork out of the process.

Appreciated.

Submitted by bruce_kirby on Wed, 27/04/2016

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Previously Phil Hannam wrote:

Does this Australian posting help?

I think that this says it all, Phil.

Interesting note about the conflicting/different sizes of the RLS 9 bearing.

Interesting too is the differing opinions on whether or not to put a roller in place for the layshaft.......

 


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