I am rebuilding a BSA plunger framed gearbox at the moment and am looking for a supplier that can hopefully supply all of the bushes required.
I believe the main case and inner covers are the same as M20 with only the outer cover being slightly different.
I am hoping to be able to get them all from one source without having to contact numerous suppliers.
Can anyone recommend a supplier.
email (option): mfarnay@bigpond.net.au
If you are talking plunger B or M series (not A7/10) you are correct...All the bushes are identical to WD models apart from the inner cover layshaft bush which is cut away for the speedo drive worm fitted to plunger variants....
Russell Motors (UK) are probably the best source for these bushes and the place where you are most likely to get NOS, though I know they have had some of them remade...They also cover B Series models (engine and gearbox) as well as WD models, so you may get the 'odd' bush from them as well....
I see you are in OZ...Can't help you there I'm afraid!...Ian
email (option): ian@wright52.plus.com
Thanks Ian. Yeah I should have said B series.
I am not expecting to get them in Oz. I had thought of Russels or maybe draganfly.
I wonder if you can tell me if the layshaft bush in the case is a press fit or does it screw in. The main bearing and the selector shaft bush came out pretty easily after heating, but the layshaft bush didn't want to move. So I thought it may screw in as it has a cross cut in the top of it that looks like it may take a tool.
email (option): mfarnay@bigpond.net.au
Hi Mark...All the bushes are a plain interference fit when cold and should come out without too much effort using a suitable drift and a hammer when the case is heated...You have to remove the speedo drive worm and layshaft first...
When refitting I generally heat the case and cool the bush and they usually go back in easily...The bushes in the 'blind' end of the box can be awkward to get at, especially if the case is hot, and it's worth making some suitable shouldered drifts (of the appropriate length) to make refitting easier....Also work out how you are going to hold the case firmly before you begin the job....Ian
email (option): ian@wright52.plus.com
Thanks for your advice Ian.
Everything is apart. The case was heated at 150C for about 15 minutes when I removed the bearing and the other bush. I gave the layshaft bush a fair wack with a drift but it didn't budge. Might try the press next time for a more gentle approach.
I assume the same approach can be used for the bushes in the gears? Or use the new bush to drive out the old one while installing at the same time?
email (option): mfarnay@bigpond.net.au
The layshaft bush comes out towards the inside of the gearbox but the speedo drive and layshaft must be removed before trying to remove the bush...
The speedo drive worm is retained by a special screw, the slotted end of which you will see inside the cover...
It is important you follow the correct sequence to remove this screw...First loosen the nut that is screwed onto the end of the speedo drive where the cable is attached...Next give the end of the drive a light tap with a hide mallet...Then try to undo the retaining screw...Once the screw is out the speedo drive assy. can be drawn from the cover...It may be a tight fit and you might have to lever carefully between the outer nut and the cover to get it moving...
This can be an awkward procedure...If you cock it up and damage the speedo drive I have plenty of spare ones if you can't find one locally...
Once the speedo drive worm and its brass holder are removed from the cover the layshaft will come out in your hand as there is then nothing retaining it..
You can then drift out the bush towards the inside of the box...
When removing the bushes in the gears you can remove them cold with a suitable drift...I wouldn't use the new bushes to do this as they are thin and easily damaged....DO NOT heat the gears at all...it isn't necessary or desirable...
The sleeve gear (the one the gearbox sprocket sits on) requires special treatment...are you planning to replace those bushes as well?...Ian
email (option): ian@wright52.plus.com
I withdrew the speedo drive as per the manual. It took 4 progressively longer spacers using the nut to draw it out. It was pretty tight all the way.
I was thinking about replacing the sleeve gear bush although the gear itself is showing a bit of spalling on the teeth.
So what is the procedure for dealing with this bush Ian?
email (option): meck04@bigpond.com
You will see that the sleeve gear has three oil drillings through it (between the gear teeth)...These also go through the wall of the bush and provide an access for oil to lubricate the bush...
New bushes are not generally pre drilled so the holes need to be drilled at the point of fitment...However, the holes run through the gear and bush at an angle.
The diameter is fairly small and the result is that the drill is prone to snapping due to the uneven forces applied as it breaks through the bush at an angle...
I have found it best to fit the bush, drill only enough to 'mark' the holes positions and then remove the bush and drill through with a slightly oversize drill, say 3/16" diameter...Then press the bush back in, taking care to align the holes correctly with those in the gear...Ian
email (option): ian@wright52.plus.com
Yeah I noticed the oil holes at an angle.
It sounds like it's a toss up whether it's easier to drill very carefully all the way through or drill to mark, remove and drill through then refit hoping the holes are going to line up. :fearful:
Or just press out enough to get at the holes then press back in.
Other than that the replacement procedure is the same Ian?
I picked up a couple of bearings locally yesterday. Both sealed. Is it desierable to leave the seals in place on the small bearing in the inner cover? And what about the shim behind the bearing? Can that be left out if the seals are left in place. Or is oil supposed to flow through the bearing to the outer cover?
The supplier said that the large main bearing was metric. Wasn't expecting that.
Sorry to bombard you with so many questions Ian but none of this stuff is in the manuals.
I do appreciate the time you take answering all my lame questions. Thanks again Ian.
email (option): mfarnay@bigpond.net.au
I wouldn't try to drill the bushes in place...My advice comes from having broken drills myself in the past...Pressing the bush out halfway before drilling but after 'marking'it would work fine I would think...All pressing should be done cold...With care you can use a vice to 'press' them in and out if you don't have access to a press...
I have seen either one piece bushes or two separate bushes in sleeve gears...If you have two bushes do the drilled one first and after that is fitted fit the second one...That way the second bush (which isn't drilled) doesn't get in the way as you press the first one in and out...
I would recommend removing the inner seal from the gearbox main bearing as the gearbox oil cools as well as lubricates the bearing....You don't need a sealed bearing at the inner cover end as it is within the gearbox and there is oil on both sides of it...Just remove the inner seal from that one as well for the reason noted above....I think the shim is there only to help retain some oil in the bearing when the gearbox is running...it is not really an operational 'seal'.
However, I would leave it in place as it will affect the positioning of both the main shaft and the ratchet gears etc. if you remove it...The same can be said of the main bearing shims in relation to the sleeve gear and gearbox sprocket...
Strangely, BSA used a mixture of Metric and Imperial bearings in both the engine and gearbox...I have no idea why, when they were working at a time where the Imperial system was the standard...Ian
email (option): ian@wright52.plus.com
What would be the idea behind the 3 holes in the sleeve gear?. Don't think the oil will go to the shaft when running.... It will rather spin out. Would they be there to get a circulation going?, so that the oil goes in along the grooves in the mainshaft and exits through the holes?
Regarding the large shims along the mainbearing, I have found the when the shim on the chainside is not totally flat it can touch the sealing of the bearing and lock the sleeve gear up after the sprocket has been fastened. So I now cut the outside of the shim so that is fits from the other side of the casing. This gives the addition advantage that you don't have to bother about a shim when fitting the bearing in the hot casing.
email (option): m.wijbenga@hotmail.com
['What would be the idea behind the 3 holes in the sleeve gear?. Don't think the oil will go to the shaft when running.... It will rather spin out. Would they be there to get a circulation going?, so that the oil goes in along the grooves in the mainshaft and exits through the holes? ...']
That's a good point Michiel and sounds quite plausible....Ian
email (option): ian@wright52.plus.com
Hi,
could it be that there are 2 different kinds of bushes, here ?
One straigt and one with a little edge on the inside of the gear box ?
If so, maybe the second type was for the plunger frame gearboxes..?
Ian one more question then I will leave you in peace.
Do any of the bushes need reaming?
email (option): meck04@bigpond.com
Hi,
At the past I opened a thread for “A tight gearbox”.
http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1360327&cmd=show
Well, it doesn’t have to do with this current thread, but someone wanted to know
What will happen with it after running for a while, so after installing all on the bike,
The kick-start ratchet was slipping most of the time, and if it did not,
It would turn the motor half way and then stucK solid.
I replaced the entire right gearbox cover with another one I had. It made the kick start work wonderfully,
And I think it also freed the tightness. It is hard to know, as the gearbox was already on the bike,
But I do remember that on the bench, when I loosened the cover screws a bit, the gear turned better.
Anyway, I have done almost 700Km on it by now, (435 miles) with a 720cc engine, and all works fine.
I got to speeds over 100 KPH (62 MPH) with no issues, so I hope I am out of the woods with this…
Just FYI..
Cheers,
Noam.
email (option): noam10@gmail.com