layshaft wear advice

[oceanobsession]

Hi folks , stripped the gearbox down , layshaft blind bush side worn , also slight play in through bush , heated gearbox shell removed the blind bush  and large bearing , thinking about buying a new layshaft ebay old stock a bit rusty , fitting new bushes
but do they need line reaming , ive got another layshaft that is only worn on the blind bush side , so i could have this machined
and get new bushes made which would need line reaming , i know srm do this work but not cheap , are there any other options
a quick look at everything else seems ok , lots of spare gears  , phil.     

[RDfella]

I usually - when necessary - machine the end of the layshaft clean and make a new bush to suit. Because it's blind it cannot be reamed. Must be machined for clearance on the shaft + half the interference fit of the bush in the case (it'll close up when fitted, usually by half the interference fit).

[KiwiGF]

Hi folks , stripped the gearbox down , layshaft blind bush side worn , also slight play in through bush , heated gearbox shell removed the blind bush  and large bearing , thinking about buying a new layshaft ebay old stock a bit rusty , fitting new bushes
but do they need line reaming , ive got another layshaft that is only worn on the blind bush side , so i could have this machined
and get new bushes made which would need line reaming , i know srm do this work but not cheap , are there any other options
a quick look at everything else seems ok , lots of spare gears  , phil.   

I vaguely remember my engineer guy made a special bush that had a screw on “cap” so he could line ream the blind bush, or at least ream it, obviously if that is possible it will cost more.....

This was after making the shaft round again, and the bush was undersize as well. Undersized bushes are or at least were available in the after market, but that means reducing the shaft diameter more than necessary.

[Swarfcut]

  A needle roller box has a welch plug to seal the open end of the bearing so a custom open ended bush and plug will do the job if you really want to go down  the perfection route with line boring/reaming.

 From experience these boxes still  function reasonably well with mix'n matched parts. Most moan in 3rd gear, but in top gear the layshaft is not under any great load and the blind bush has an easy life. Quiet boxes have been taken down only the find the blind bush a shadow of its former self and the layshaft with almost thread on the end. Don't get paranoid.

 Plunger layshaft is dimensionally the same, but differs in position of the circlip. Hardly a problem if care is taken to press on the S/A layshaft pinion, leaving out the circlip. Plunger layshaft, layshaft pinion and layshaft 3rd gear will swap into a S/A box. Not for the purists, but may help get a working box. Plunger layshaft has a plain blind bush end, S/A has a scroll. So an easy visual check.

 Swarfy.

[oceanobsession]

Thanks folks for your help and advice , there was a complete gearbox in my spares that came with the bike , it had a welded case
and looked in very poor condition , anyway it had a new layshaft and bushes fitted with no play whatsoever , hopfully i can fit the bushes in my good condition case and use the layshaft ,im going to get all the covers vapor blasted first , and send the studs bolts and nuts in for zinc plating then reassemble everything , hopefully the layshaft will be ok if not im looking at new bushes and a line ream , even if everything is perfect i think these layshaft wear out with mileage , may be changing the oil regular will
help , phil.