Bearing Shim Drive Shift A7 1948

[trevinoz]

Peter,
              Did you leave the outer seal in the bearing? To my mind, it would serve as well as the original "shim" in keeping crap from the chaincase from entering the crankcase.

Trev.

[Peter in Aus]

Hi Trev No I took it out as those seals are one way they let stuff out but not in so would actually pump oil out against the scroll on the sleave.
Cheers
Peter

[trevinoz]

I don't follow your logic, Peter.
                                                       Surely an open bearing will let more oil through than a sealed version and leaving the seal in place is exactly what you want, preventing the entry of material from the chaincase to the crankcase.
If the seals are "one way", why doesn't the grease escape?
With the inside seal removed, oil would take the line of least resistance and flow back into the crankcase.
Just my thoughts, right or wrong.

Trev.

[Peter in Aus]

Hi Trev Well you might be right and you might be wrong but the proof is in the pudding there is no oil getting into the primary chain case or going the other way as the oil level is remaining the same, so in my mind that seal/shim is not required as long as the sleave has a scroll in it and the scroll section of the sleave is a good fit in the crank housing, just what that tolerance is I don't know maybe some one out there will inform us?
Cheers
Peter

[duTch]

  I have mine apart to replace a busted spring, so have tooken some notes...and some pictures, but too complicated for them now.....hoping am not doubling up on info here..??

The part in question is clearly itemised in parts book '49-'53, pages 11/12 Plate 1/ item 81- Bearing shim (Drive side).

  As I said previously, was sure I originally had one, but I think I had the original 'Cush Bearing' ( same as in Trevs' photo 'scrolled sleeve' ) ground down to ~1.675" dia., and casing machined to accept the seal.

 I have another bush without the scroll, which is similar to Trevs' 'Plain bush', (dia. ~1.803)  too large to work with a seal, so can only guess which era may be from, but may use it later on .

 It seems to work ok, but means modifying the case.

 Pete, by using a sealed bearing, I'm assuming it's a ball bearing?

 

[Peter in Aus]

Hi Dutch Yes it was a sealed ball brg. & I removed the seals
Peter

[Brian]

Peter I see in a earlier reply you say you took one side out of a sealed bearing and put oil in and it ran out. If the bearing was not damaged that can not happen. The seal in these bearings will easily hold oil.

I'm wondering if you are confusing a "sealed" bearing with a "shielded" bearing. A sealed one has two rubber seals, hence the number and letters 2RS on the end of the bearing number. A shielded bearing has two metal shields in it, basically they are to keep big lumps out and will not hold oil.

Many of us fit a sealed bearing in the gearbox with just the outer seal left in. I do this on all my bikes and have some that have done thousands of miles and still dont leak.

I use a ball bearing on the crankshaft in my plunger bikes with the seal left in the outer side, once again some have done lots of miles with no leaks.

[Peter in Aus]

Hi Brian It was a sealed brg. 2RS with rubber type seals I can only tell you what I did and what happened, my plunger engine has both seals removed from the brg. and it dose not leak, also the gearbox main brg. used was not of the sealed type, it has the normal seal on the out side and that seems OK so far, the only thing I can suggest is the next time you get a sealed brg. try cleaning it out and filling it with oil and see if you come up with the same results as me?
Cheers
Peter