My VB Restoration Blog

[dave.owen]

more pictures

[paul.wirdnam]

Dave, thanks for the pictures! So you now have a real rarity --- a hinged, centre bolt lid toolbox.

Looking for some advice on gearboxes and clutches for my VB project. I knew I'd bought a collection of VB parts but hadn't realised that so much of the clutch was missing, and what I do have is fairly shagged out. I also hadn't appreciate that these late 1930's Burman clutches were not the same as my Black Ariel, Cammy or Sloper clutches, so I have no parts....and, worse still, no knowledge.

I've done the usual; trawelled through very useful exploded parts diagrams on Draganfly site etc but still have questions. I'll start off with a few photos of what I do have:





From what I've learnt to-date, these clutches have needle roller bearings with the inner race being part of the main shaft and the outer race being a part that the sprocket is attached to. And the needles are held in the brass cage in the photo above, with trust washers either side.

Here is my first question: I don't have the sprocket or the outer race part. Looking at Drags, I can see that I can buy a new sprocket and dowel pins (3380-94) but these are designed to be pushed onto this outer race part that I do not have. Do Drags sell this part? If so, can someone tell me the part number because I'm not sure what it looks like, as I can only find photos of the complete sprocket and race assembly.

In the second photo above, I soon realised that this clutch centre is not for the BA box that came with the bike --- the splines in the clutch centre are too long. Drags site says Burman, in 1948, lengthened the splines on the clutch main shaft and added a boss to the clutch centre to lengthen the splines here. So my BA box is pre-48 and my clutch centre is post-48.

Next question: it seems I can buy a new post-48 clutch centre with boss easy enough but the one with the shorter splines and no boss are harder to come by. Any reason why I shouldn't buy the more common one and remove the boss on the lathe? They look identical in all other respects.

This spline mis-match between my clutch centre and my BA box prompted me to go through my small collection of BA boxes and see what sort of main shaft ends they had. Not looked at these for many years; one BA box has "£30" written on the side...when did you last see a BA box for that price . These are not necessarily from Ariels but I'd appreciate any info you might have:

1) Short spline. The one that came with the VB



2) Short spline. Spare



3) Short spline. Spare. But seems to be a CP box.



4) Long spline. Spare, But no markings / stamping on this box.



5) Early 1930s hand change box with smaller diameter clutch. As used on Sloper, Cammy.



6) Early 1930s hand change box with smaller diameter clutch. As used on Sloper, Cammy.



Last question (for time being!): I probably won't bother doing this but if I wanted to use a clutch centre / gearbox mainshaft combo with the longer splines, are the short and long spline mainshafts interchangeable? Could I take that shaft out of box #4 above and put it in #1?

If you got this far, thanks for reading!

[dave.owen]

Paul, I believe club gearbox spares have the parts you need. Peter kemp single spares also stock the clutch plates.

Dave

[simon.holyfield]

I searched my blog on 'clutch'. There might be one or two useful pictures.

http://ariel-square-four.blogspot.co.uk ... clutch?m=0

[paul.wirdnam]

I searched my blog on 'clutch'. There might be one or two useful pictures.

http://ariel-square-four.blogspot.co.uk ... clutch?m=0

Thanks...took a look. What is the white grease you're using on the needle rollers?

[paul.jameson]

Paul,
A quick reply but don't interchange mainshafts or layshafts between pre and post 1948 gearboxes. The differences are hard to spot but can lead to 2 gears engaging at the same time with consequent loss of teeth. I found out the hard way.......

[paul.wirdnam]

Paul,
A quick reply but don't interchange mainshafts or layshafts between pre and post 1948 gearboxes. The differences are hard to spot but can lead to 2 gears engaging at the same time with consequent loss of teeth. I found out the hard way.......

Thanks Paul...good to know.

I've now ordered all the pre-1948 clutch parts from Geoff Brown (AOMCC Gearbox Spares). I'm always amazed at some of the parts the AOMCC has had made. There was a heavily used clutch basket and a couple of steel plates being sold on eBay yesterday and they went for £65....but for £5 more, I can get a new basket from the club! We need a "thumbs up" smiley on this Forum, but in the meantime, I'll supply my own:

[paul.wirdnam]

Progress seems slow with the VB...but maybe that's the way with these side valves.

I've just about finished the girder forks. If you remember, the project came with no forks at all, so lots of parts to find. Headstock piece re-bushed and with new cup and cones now installed into the frame, but I've had a few "issues" with Draganfly's quality control --- don't get me wrong, I love Draganfly and I don't know what we'd do without them, but I do seem to be sending back 25% of what I buy either due to wrong item sent or poorly made part.

The steering damper trunnion (4903-35) below is a case in point. The first one arrived with a milled slot that was only big enough for a 3/8" fork spindle; I thought I was going mad or that Drags had sent a BSA one or something. Turns out the guy in Essex who makes them for Drags only half finished some of them. The second one to arrive had the correct sized slot for a 1/2" spindle but now the outside diameter was too big to pass into the headstock piece (4800-33). I wasn't going to send it back again, so stuck it in the lathe and reduced the diameter --- shame as this took off the zinc plating as well but as there is gallons of grease in this area, I'm not too bothered.



Maybe someone can comment on the following photo. Is this another manufacturing issue with these covers and horn mounting platform? I can easily rectify but don't want to start removing metal unnecessarily. The inner cover at the top centre touches the frame down tube; there is a shallow cutaway on the plate that I assume just needs to be deepened to clear the frame a little better. But the battery platform is tilted upwards by a long way; again, is this just a matter of removing metal from the inner shelf edge so that it is free to drop to the horizontal?

[simon.holyfield]

My battery platform was like that. I elongated the holes if I recall correctly; I don't mind doing stuff like that, because as you say we would be lost without them, but this kind of thing is the reason we end up making missing bits ourselves isn't it.

[paul.wirdnam]

Rainy day, so a good time to have yet another go at the seized piston. I bought the engine without a head and knew it was seized but I really believed I could free it off. The barrel has had numerous heat / cold cycles, and had all sorts of fluids / potions / mixtures (Coke, diesel, penetrating oil, 50:50 acetone: tqf, etc etc) poured on top of the piston.

But it was not to be....and since I had bashed the piston so many times (via a block of wood!), I decided I'd never trust this piston anyway, so got my drill out....







In the above photo, I was well below the 3 piston ring level and still could not shift the piston Finally decided I'd have to cut a groove from top to bottom to release the piston from the sides. This finally did the trick. The bore is not damaged at all and the rings have left no mark on the bore....it seems it was seized due to surface corrosion on the aluminium and the large surface area that a 600cc piston has: