A10 main shaft play.

[frogeye1000]

In the middle of replacing gear box oil seal and I have found that there is some play in the main shaft/bush where it exits the sleeve gear for the sprocket. It only amounts to a couple of thou' or so up and down. No end float. Is there a tolerance for this or would it be ok to carry on running.

Cheers

Richard.

[muskrat]

G'day Richard.
Better of measuring the "up & down" at the end of the shaft. "A couple of thou" at the seal will be quite a few thou at the clutch nut.
Cheers

[frogeye1000]

I see what saying musky,

I meant at the end of the shaft rather than where it exits the sleeve gear.

If a new bush were fitted, I've read they need honing out. Can this be done with a wooden dowel and some Emery paper,  and is it possible to change it with the gear box in situ without too much jiggery pockery .

Richard.

[CheeserBeezer]

Officially, there should be no play at all but, in practice, I would expect to find a couple of thou. The gearbox on my Super Rocket had a lot of play in the sleeve gear bush but, in spite of this, the bike ran fine.  From your description, unless you were planning on taking the gearbox out, I'd carry on using it as it is. It is a big job. The gearbox has to come out and be completely dismantled, then new bushes fitting in the sleeve gear and carefully honed out to accept your mainshaft. You definitely can't do this in situ, nor can it be done without the proper tool which would be an expanding reamer or lathe.

[Triton Thrasher]

A couple of thou at the end of the shaft is not a problem.

[Swarfcut]

 It's a somewhat delicate balance. Too tight and there is a risk of seizure. Too loose and you get the  bigger oil drip. In top gear both mainshaft and sleeve gear rotate together, so not a problem in the grand scheme of worn chainwheel teeth and well used primary chain. and at an estimated 2 Thou lift you probably have one of the best in current use.......The bush may be on spec, and it is the shaft that is worn. Either way, a lot of work and expense for true perfection, back in the day these bikes ran fine with oil drips and slack, it's best left until major overhaul is required.

 CB is on the money here.

 Swarfy.

[limeyrob]

Oil level is below the bottom of the seal so there should be very little seepage when stopped.  Side stand could be an issue, not sure.

[JulianS]

Use an SRM nut with oil seal to stop the annoying dribble. Easier to tighten with the hex too.

[frogeye1000]

Thanks for all your replies.

I have bought the srm seal nut along with a new gearbox seal , chain wheel and chain due to it snapping. My concern was the play would be acting directly on the seal part of the nut.

I'll reassemble it and see what it's like.  There were no issues with it before and the only reason I have it apart is for a snapped primary and a damaged chain wheel.

Regards
Richard.

[BSA500]

Yes the SRM nut is a good replacement and easier to do it up. And yes its a pig of a job to replace the bushes . When the seal goes on the nut I found a place that supplies those for a couple of quid