First gear pinion on mainshaft interchangeability

[duTch]

Yeah Kiwi bugga 'bout the shaft, but don't ditch it threads can be redeemed... maybe?

  As John says/inferred,  nice snug fit sounds good, I had a little grief wit mine too when I reassembled, just gotta go steady steady. I think personal choice on the reassembly, mine being Bolt-on, put the guts in place then pulled the mainshaft out to put in the inner cover bearing, and jiggled back together, but yours is S/A. Just make sure you get the index marks right as discussed a little while back, not hard, steady steady.

cheers duTch

[KiwiGF]

Thanks John/Dutch - this confirms what I suspected, this being the shaft should not have been as tight in the bearing as it was. I managed to crack the shaft where the thread/kickstart spline is  .

If I was was desperate the shaft could be fixed but it would be a "mission". I've ordered a used one from a local supplier and fingers crossed it's in good enough condition to use (tapers and key slots tend to be knackered on them of course...). I should know it's condition when I get home tonight.

I've made a right mess of the fixing up the box! I fitted/reamed new sleeve gear bushes but am I'm now having to use the plunger box sleeve gear to pair up with the better condition plunger L/S gear, as per above posted advice - so I might be waiting for parts and re-doing the sleeve gear bushes again.

I just hope I get my act together once I get the engine parts back from the machinest....(fixing mismatched cases, oversize plain main bearing housing, distorted barrel bottom face, bad threads etc). I'm still planning to have the bike ready for next March's National BSA rally in the Wairarapa (especially as I am helping in the organisation of the rally). That's not a very difficult target....... one would think! (but my original target was LAST years rally, in Dunedin).

[duTch]

Kiwi,
  Just a thought- I presume you have the correct (imperial size) bearing? Don't know how close a metric one is to size, could be close enough either way to cause grief?
cheers

[KiwiGF]

Hi Dutch I'll measure the various parts up and report back, I guess a thou might make all the difference.

The local supplier sent me a mainshaft off another bike, I'm not sure if they can supply the right one but I'm not holding my breath!

[duTch]

The bearing should have a number on it, if you didn't replace it and it was correct to start,-reckon it should've gone back in ok!!??
 But as I said I had a similar moment with mine but can't remember what I did(fairly sure I put a new bearing even though old one was ok??)

 Just don't go blue like those little ranty blokes!! tho' they are entertaining

[KiwiGF]

Dutch, bearing is new from Draganfly in box with L 3/4" on it but I will measure it and the 2 shafts etc

I suspect  I need a new bearing as it was well and truly stuck on the shaft and I've probably marked the track. Blue fellahs are great. Discovered tonight. Yep I feel a bit annoyed , myself to blame with cost if new shaft I might go for using the plunger shaft and non BSA clutch

Painful given all the new 6 spring clutch parts I've already bought!

[Topdad]

Hi Kiwi, I experienced the same problem last year doing my box up. The mainshaft would only fit through that bearing after i used considerable force ,block of wood and hammer no damage to shaft but once just about together couldn't tighten cover and still turn layshaft ,turned out to be an oversize mainshaft , rub was the mainshaft was new and from Dragonfly. During the numerous attempts to rebuild the box I came up with a way of keeping everything together, simply use a rubberband to hold cogs and gearchange dogs together both main and layshaft, worked a dream . You remove the bands via the inspection plate in the side and long nosed pliers carefully.As per Dutch's post watch the dots on the inner cover and gearchange pawl ,normally dotted red ,that also caused me grief for ages until someone( wonderful person) on the forum suggested moving the dots slightly out of line ,Mine was a teabreak box and that did it been great since, best of luck BobH   

[duTch]

 I just remembered I have info stashed in my phone in front of me;-  Hoping what I have is the correct info, anyone else can please confirm??
 # RLS-6      1-7/8 x 3/4 x 9/16 That could be the bearing shop P#, but it should still cross refer.

 Don't get carried away with the 'Rantys' like I do.

[chaterlea25]

Hi Kiwi,
I'm trying to keep pace with all the changes you are making
To the best of my knowledge the inner engagement dogs on the plunger sleeve gear are different to the swing arm sleeve gear , ( I hope I'm wrong for your sakes ????)
if this is so then you would need to change the 3rd gear pair as well
(if that will work out with the engagement dogs on the opposite side ????)
More and more

On the other hand I have seen gearboxes running away merrily with a lot of wear on the gear teeth faces
and I have fitted NOS gear pairs which whine like a banshee ????

Gook luck
John O R

[KiwiGF]

Hi Dutch/John, I'll report back after a good look at things tonight. Recognise the incorrect shaft I was sent by any chance? Its the shorter one in the pic....

[KiwiGF]

Hi, I've had a look with the benefit of all the info in postings and found:
1. The mainshaft I broke is at least a thou more in diameter than the other two mainshafts I have at 0.751" and that would have caused the problem with fitting it I think, maybe same as yours Topdad? The new bearing it was supposed to fit into is the same inside dia as others I have at 0.750" maybe less a bit.
2. Of the 8 gears only one seems to be too different to fit in both boxes, plunger or s/a, that being the l/s gear nearest the clutch that engages with the sleeve gear has slightly different dogs, but even that gear looks to be only different due to the plunger l/s being slightly different, or in other words fit a plunger l/s in a s/a box and that gear would also fit in a s/a box.
3. So the gears marked v16 (from plunger box) look interchangable to those marked en36 (from s/a box) but given advice to the contrary that are not a compatible material or shape I'm not going to mix and match v16 and en36 gears, but I sure could understand people giving that a go!

I'll post pics in due course of the gears/shafts.

[KiwiGF]

So heres a pic of one side of all the gears, on the left the gears and 2 shafts taken from a plunger "semi unit" box, the gears are marked with V16 albeit some markings are incomplete. On the right are gears and shafts taken from a 56 swing arm box most of which are marked EN36. The far left has the layshaft gears from the plunger box. I've shown just the "dog" side of the gears as the other sides all appear identical.

So the visual differences are:

1. The layshafts have the wire spring clip in different places on the shaft, this means the gear kept in place by the clip will not fit on both layshafts. The inside of the gears dogs are machined away on the plunger gear to allow the gear to slide further over the clip. My guess is the s/a design is stronger as more gear engages with the hex shaft. Without trying it I would say the plunger layshaft and that gear would fit into a s/a box, if one really needed to use that gear, but see below ref lube provision for the plunger layshaft. There's a close pic of the end of the shafts showing the difference (pic 227), also a close up of the inside of the 2 different gears (pic 224).

2. The plunger layshaft does not have a spiral groove for the drive side bush. The bush also does not spiral groove either box, I guess the groove on the s/a shaft is to improve the life of the bearing, the bush in the plunger box has a longitudenal slot I guess in place of a spiral on the shaft. the s/a bush does not have this cutaway.

3. The dogs are different on two of the plunger gears, the m/s gear next to the sleeve gear, and the l/s bottom gear. There's a pic of the bottom gear in an earlier post and the other gear from each box are in pics below (pic 225 and 226). My guess is these changes in design are to increase strength rather than gear changing but I could be wrong, the design change did not appear to require a change in design of the gear the dogs engage with (this assumes the boxes I a have contain original gears of course!).

4. The washers on the layshaft are of different thickness, though I'm not sure if that is caused by wear, or to get the end float correct.

Anyway, I hope all these posts that adds to the forum knowledge and helps someone.

My problem (edit: now all answered/solved thanks all) has now switched from being whether to use a V16 bottom gear in a s/a box (it is has slightly different dog design to the EN36 gear) to sourcing a new mainshaft (or maybe I'll use the plunger mainshaft and spend the money on a better clutch instead).

[duTch]

Hi Kiwi,
           First thing that came to mind is, wouldn't the 'engagement factor' still be governed/determined by the 'throw' of the selector forks??
        Otherwise my attention span at the mo' is kind of short-had a big night last night, but maybe can suggest slipping in the images next to the description, might save scrolling up'n down ??
      Cheers for now duTch

[KiwiGF]

High Dutch, I'll see what I can do ref pics but I just added them at the end, no obvious choice on position but I'll work on it.

Engagement factor if I understand that correctly is the same either gear, but with en36 gears its not just the dogs that engage but the other teeth as well? which is stronger, if that makes sense?

[Caretaker]

I'll see what I can do ref pics

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