Burman 4th Gear Selector Meltdown
- Thread starter tatty500
- Start date
I just nicked this off "Our Resources ", In case anyone missed it.
Maybe no good for Brian, But I think it's worth a watch. I know it's not our type, But close !. Cheers Bill.
Maybe no good for Brian, But I think it's worth a watch. I know it's not our type, But close !. Cheers Bill.
Hi Brian
As I said I used the dragonfly spacer with its oil seal with no problems though I may have put one of the old seal washers in as well to make sure the circlip held the bearing tight, though the bearing was a tight fit in the casing plus some Loctite. - I can't really remember all the details now.
I can remember it was quite a job to get the circlip in properly and I had a groove cut into the periphery of the Dragon spacer to take a very thin large diameter O ring to ensure no oil got past the spacer.
It has all worked very well for a few thousand miles now.
Matty
As I said I used the dragonfly spacer with its oil seal with no problems though I may have put one of the old seal washers in as well to make sure the circlip held the bearing tight, though the bearing was a tight fit in the casing plus some Loctite. - I can't really remember all the details now.
I can remember it was quite a job to get the circlip in properly and I had a groove cut into the periphery of the Dragon spacer to take a very thin large diameter O ring to ensure no oil got past the spacer.
It has all worked very well for a few thousand miles now.
Matty
Hi Brian again
You must be a very patient and younger man than me because taking the whole gearbox in and out a few times is quite a bit of work because it includes rebuilding the clutch with its roller bearings each time etc. which I find very hard work at 83 !!
To just change some parts however - for instance, to replace my original bent layshaft which was still working though noisily after about 60years,- I have left the mainshaft in with a rag behind the clutch to stop it moving out.
However why not buy a spacer from Draganfly with its oilseal to see if it will fit - first making sure the bearing ( hopefully with its oilseals still In) is firmly shrunk in and back against the flange in the casing.
I then fiddled around with suitable spacers so that the circlip would just go into its groove.
I may not in fact have used any spacers and perhaps used one of the old rubbery oilseals.
Draganfly are quite a helpful business and may perhaps sell you a spacer on a sale or return basis to see if it would fit.
All the best
Matty
You must be a very patient and younger man than me because taking the whole gearbox in and out a few times is quite a bit of work because it includes rebuilding the clutch with its roller bearings each time etc. which I find very hard work at 83 !!
To just change some parts however - for instance, to replace my original bent layshaft which was still working though noisily after about 60years,- I have left the mainshaft in with a rag behind the clutch to stop it moving out.
However why not buy a spacer from Draganfly with its oilseal to see if it will fit - first making sure the bearing ( hopefully with its oilseals still In) is firmly shrunk in and back against the flange in the casing.
I then fiddled around with suitable spacers so that the circlip would just go into its groove.
I may not in fact have used any spacers and perhaps used one of the old rubbery oilseals.
Draganfly are quite a helpful business and may perhaps sell you a spacer on a sale or return basis to see if it would fit.
All the best
Matty
Hi Matty thanks for the encouragement. Having done this job several times the most frustrating part is for me, replacing and removing inner cover as there are studs , gear cam shaft with rollers and tight fitting main shaft all to be orientated. Yes. I did utilise your idea for cushioning out the clutch basket against the cover.
On the Draganfly site they are quite specific about measuring the depth available in the case to the main shaft bearing 3095-33 drive side as in some instances there is insufficient depth for their replacement seal. I will investigate this as soon as the 52mm socket arrives to remove the gearbox sprocket unless my patience does desert me and I go neanderthal with a chisel and lump hammer!!
Hopefully there will be a conclusion to this even if it involves greater £££.
On the Draganfly site they are quite specific about measuring the depth available in the case to the main shaft bearing 3095-33 drive side as in some instances there is insufficient depth for their replacement seal. I will investigate this as soon as the 52mm socket arrives to remove the gearbox sprocket unless my patience does desert me and I go neanderthal with a chisel and lump hammer!!
Hopefully there will be a conclusion to this even if it involves greater £££.
Have a good Birthday , Brian, Hope you get a working Gearbox for a present !!. Cheers Bill.
Matty
I've usually withdrawn the mainshaft and clutch in one piece before removing the shell.
Brian, even with a socket or box spanner available, it was more stable in my vice to grip the nut and turn the sprocket with a chain whench or soft metal drift towards the bottom of the teeth.
Tatty
I've usually withdrawn the mainshaft and clutch in one piece before removing the shell.
Brian, even with a socket or box spanner available, it was more stable in my vice to grip the nut and turn the sprocket with a chain whench or soft metal drift towards the bottom of the teeth.
Tatty
i may get laughed at for this post but here goes.
where does the lack of lubrication fit into this as i cant remember where i read this, that the burman grease box runs dry of grease as its flung outward cutting a cavity between the gears. (depending what is in there), i think most of us use liquid grease, if this cures that) ......long haul jouney ...no lubrication...somethings got to give..oh and one more thing how can one be confident that liquid grease will penetrate past the inner cover, as its thicker than treacle how can that get past the inner cover ?
where does the lack of lubrication fit into this as i cant remember where i read this, that the burman grease box runs dry of grease as its flung outward cutting a cavity between the gears. (depending what is in there), i think most of us use liquid grease, if this cures that) ......long haul jouney ...no lubrication...somethings got to give..oh and one more thing how can one be confident that liquid grease will penetrate past the inner cover, as its thicker than treacle how can that get past the inner cover ?
Also remember that the bronze (not Oilite) bushes on the layshaft are lubricated through 1/8" radial holes in the two free gears. As Richardson or someone says, an eggcup of oil occasionally is a good idea. I seem to remember a par by P.E.I. to the effect that grease channels, but doesn't leak, oil leaks, but lubricates. Also folks, the Spares Co. site has all the right "Vincent" part numbers which agree with the Spares List, although I concede that the Draganfly illustrations are much clearer. Many years ago at the Peppin Point rally my gearbox screeched and a bit of oil cured it immediately, just like the book said.NOTE: Most, if not all Vincent gearboxes, 1949 and later, have these bushes, earlier gearboxes do not.
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Hi
I think the tunnelling effect may have been a factor many years ago when we used thick grease, but the newer liquid grease from Classic lubricants the Club or Draganfly flows quite well and in fact may be thixatropic ie. like non drip paint and only becomes liquid when disturbed.
I have had the screech many years ago with grease which as you say was fixed with a cupful of oil.
My layshaft bushes have been replaced now with oilite ones because I had bronze ones which seized onto the shaft, turned in the casing and damaged it, even though I was using liquid grease from Draganfly. The casing then had to be bored in line and oversized oilite bushes made and fitted. The book says somewhere that the bushes should be oilite but I do not know what the VOC spares ones are made of.
Because my box leaked grease from round the gearchange mechanism on long runs, I blocked the holes connecting the inner and outer casings hoping to lubricate the positive stop area separately, but grease still got from the gearbox out to the outer casing somehow - probably through the bearings.
There is a fix for the gear lever leak from a Swiss member which involves a modification to fit O rings to the output bearing - some fairly simple lathe work is involved on this bearing in the outer casing and it has worked very well for me and I hardly had any significant leaks on my recent 1000 mile journey to the Isle of Man and back for the Manx Rally.
I must confess that I have had more problems with the allegedly bulletproof Burman box in the 63 years I have owned the Comet than with any other part, but in general the old bike has been very reliable and not let me down on the road, though have had about 6 magneto repairs to fix starting when hot.
I have now fixed this condenser problem by substituting it for a Brightspark Magnetos easycap condenser which is fitted under the points assembly instead of the insulator, AFTER REMOVING OR CUTTING THE WIRES to the old condenser in the magneto armature. There are excellent instructions on how to do this on Brightspark's site, but I have often had to burn out old araldite or some such round the old condenser with a soldering iron to get at the condenser wires when doing the job for other VMCC members.
Good Riding
Matty
I think the tunnelling effect may have been a factor many years ago when we used thick grease, but the newer liquid grease from Classic lubricants the Club or Draganfly flows quite well and in fact may be thixatropic ie. like non drip paint and only becomes liquid when disturbed.
I have had the screech many years ago with grease which as you say was fixed with a cupful of oil.
My layshaft bushes have been replaced now with oilite ones because I had bronze ones which seized onto the shaft, turned in the casing and damaged it, even though I was using liquid grease from Draganfly. The casing then had to be bored in line and oversized oilite bushes made and fitted. The book says somewhere that the bushes should be oilite but I do not know what the VOC spares ones are made of.
Because my box leaked grease from round the gearchange mechanism on long runs, I blocked the holes connecting the inner and outer casings hoping to lubricate the positive stop area separately, but grease still got from the gearbox out to the outer casing somehow - probably through the bearings.
There is a fix for the gear lever leak from a Swiss member which involves a modification to fit O rings to the output bearing - some fairly simple lathe work is involved on this bearing in the outer casing and it has worked very well for me and I hardly had any significant leaks on my recent 1000 mile journey to the Isle of Man and back for the Manx Rally.
I must confess that I have had more problems with the allegedly bulletproof Burman box in the 63 years I have owned the Comet than with any other part, but in general the old bike has been very reliable and not let me down on the road, though have had about 6 magneto repairs to fix starting when hot.
I have now fixed this condenser problem by substituting it for a Brightspark Magnetos easycap condenser which is fitted under the points assembly instead of the insulator, AFTER REMOVING OR CUTTING THE WIRES to the old condenser in the magneto armature. There are excellent instructions on how to do this on Brightspark's site, but I have often had to burn out old araldite or some such round the old condenser with a soldering iron to get at the condenser wires when doing the job for other VMCC members.
Good Riding
Matty