A10 STD Gearbox

[RESTORER]

Thanks lads. Allan, I can't see how anything can pass between the inner race and the shaft as it is a really tight fit, not as tight as the outer face in the casing but tight nevertheless. The layshaft end bush is new and the inner cover bush is almost new as I renewed all the seals and bushes, except for inside the casing, when I started this restoration and the bike has not yet been on the road.  I did not line ream because I considered that there was sufficient alignment between the cover and the casing and these would be jig/fixture bored. I did fit the oil seal, which went in easily, but what would not fit properly was the circlip, so the new bearing is maybe a little wider than the old one, not leaving room for the seal and circlip. I feel sure that the bearing is fully home as there was a change of noise as it bottomed in the heated casing. Convincing myself that the seal is not necessary anyway, I removed it and then re-fitted the circlip, although there is a small gap between the circlip and the bearing (too small for the seal).  Dave, I don't understand how the oil seal can offer protection to the sprocket, unless you mean from dirt from a faulty bearing seal, isn't the area open to the elements anyway? I will look at that nut you mention. Fair point Julian. With there being plenty of doubt shown in these letters, whilst the box is still on the bench I will re-think the whole issue and maybe rebuild. I am waiting for engine gaskets from SRM anyway so it will keep be busy.  Bess, I have no idea, so I hope someone answers that bit!!  Thanks again.

[JulianS]

The oil seals can be a struggle, some being just very slightly too large in outside diameter to fit comfotably in the recess and if not fully inserted the circlip is very difficult to fit. When last I fitted a new seal I ot it from Priory Magnetos, complete with new circlip and it fitted very easily.

According to my digital vernier the original seal od is 71.78mm and the too large replacement 72.33mm, so about 0.5 mm too large.

[DAVE BRADY]

Hi,

My reference to protecting the sprocket was particularly the part that pushes into the seal on the spines rather than the teeth.  The seal would keep dirt away from this area.

Dave.

[Allan G]

Hi,
   

a drain outboard side of the bearing to stop the bearing hydraulic locking

Interesting, how does a bearing hydraulic lock?

Thanks...

Sorry there isn't a service sheet on this I can dig up relative to a ball bearing.

I did bring this up out of context as the subject here is about a ball bearing, sadly by the time I had realised what I had written the option to edit the post had gone, oh well it is there for all time  . I was also in a discussion about needle rollers on another forum. (How exciting!!!) however hence my mentioning of an oil drain, over over oiling can cause a needle roller bearing to skid instead of roll if there is little opportunity for the oil to escape or have an air pocket. Not an issue your going to face on a ball bearing which is splash fed with oil.

Hope this satisfies your grievance. 

[DAVE BRADY]

Hi,

Interesting to hear about skidding rollers.  Well over 35 years ago a friend was training as a Peugeot mechanic and one thing that could be problem was oil additives such as STP and Wynns.  It seems that the thickening of and increased 'oiliness' of the oil prevented the rollers from rolling and eventually they had a flat worn at the points of contact.  So worn out.

Dave.

[Bess]

Hi Allen,
           

Hope this satisfies your grievance.

It wasn't a grievance, I was hoping to discover how a bearing can hydraulically lock:

Bess, I have no idea, so I hope someone answers that bit!!

As did the OP.

Best wishes...


       

[RESTORER]

Yes, I just thought there was something I had missed, certainly no grievance and thanks for your input.  I have now had a further go at the seal fitting and understand what Dave Brady means. What I found was that, with the circlip having been pressed out in manufacture, there was a slight rad on one side and a slight burring over on the other, only slight but enough to make it the circlip a little wider than it should be and had actually scratched the slot.  I removed this lip, making both sides the same, lubricated the seal and shaft because it won't get anything from the box and have now managed to rebuild as the original, except with an extra seal on the bearing. Thanks again all.

[Bess]

Hi,
     I have done similar to yourself but very lightly packed the void with MS3 grease to keep the seal lip moist.

Best wishes...