On my 1965 B40F, the rear chain guard is held in place by a bolt which fixes a little bracket to the swinging arm, below the bottom front of the rear mudguard. That bolt is very difficult to get at and turn. Turning it a tiny amount and then taking off the spanner to turn it another tiny amount would take ages. And I imagine getting it back in again would be very awkward. Can anybody recommend a best way to undo (and replace) the bolt please? Phil.
I have the same problem on my 5TA. I took the back wheel out and gave it a birthday whilst doing the chainguard. Fettling :)
I think when BSA were building the B40 they started with the chainguard and then assembled the rest of the bike around it!! When I rebuilt mine I found it impossible to get at the bolt and nut. Solved it by drilling a 13mm hole in the chainguard opposite the bolt head which allowed me to get a socket and extension in to tighten it. Painted up afterwards and it looks fine though perhaps not for the purist.
Thanks for this, Pete. At least I'm not the only one who's had difficulty with this.
I don't see quite how you sorted it. You say you drilled a 13mm hole in the guard, opposite the bolt head, which then allowed you to get a socket and extension in to tighten it. Two things I don't get about that:
1. Looking at mine, if I tried to drill opposite the bolt head I'd be trying to drill through the bracket as well.
2. Also I'd have thought a 13mm hole would not be anywhere near big enough?
Obviously you did what you say, but I wonder if mine is different from yours. Phil.
Anyone else know a good way? Phil
I think the difference is that I was putting the chain guard on not trying to remove it. I've sold the bike on now so can't look at exactly what I did but from memory the bolt passes through the inner face of the chainguard and is secured by the nut on the inside of the bracket. The problem I had was that I had great difficulty getting at both the head of the bolt and the nut. Drilled through the outer face of the chainguard gave access to the head of the bolt. Magnetically held the nut in place and passed the bolt through the large hole in the outer face, through the standard hole in the inner face and tightened it up with a socket - cheap sockets have thin walls!!!
Not sure if this would be defined as bodgery or clever engineering!!
For removal by this method you would have to accurately mark where you need to drill the hole in the outer face. Maybe remove it by your slow method and then drill the hole when it's off. I seem to recall you can't get the chainguard off without removing the back wheel.
Picture of the bike when I'd finished it attached for interest
Can't get the chainguard off without removing the back wheel? Not the other way round? Phil
PS Nice looking bike, Pete.
Is it really true that you can't get the chainguard off without taking the back wheel off? Phil.
Phil, if you can wait a few days I might be able to tell you! My bike was missing the chainguard and I've just found one so will be fitting when I've cleaned it up and painted it.
I'm hoping that I can to it using a long 1/4" drive socket with a flexi piece in if necessary to get square on to the bolt hole. That's the theory - I'll let you know the result!
Cheers,
Bernie
Thanks very much, Bernie. I'm in no hurry. I bought a flexi drive for a socket but I don't think it's flexi enough. Phil.
By the way, Bernie, this is what mine looks like. See the little right-angle bracket? The bolt I'm trying to undo is the one at the bottom of it. I wonder if yours is the same. Phil
Quote from: Phil C on 03 Dec, 2019, 09:56
Thanks very much, Bernie. I'm in no hurry. I bought a flexi drive for a socket but I don't think it's flexi enough. Phil.
on some difficult parts Ive doubled up on the flexible joints, there is the spring style shaft but not strong enough for really tight fastners and you loose some control and can come off, or the universal joint type , a couple of them keep a good fit.
It's not very tight, just difficult to turn more than a smidgen each time, because of it being awkward to access. The spanner handle bumps into other things so I can't turn it more than a little bit before I need to take the spanner off the bolt, and reposition it to turn another little bit. At that rate, it would take ages to get it out (and same to get it back in later.) The flexi drive I've got doesn't help - it doesn't flex enough to make access/turning room any better. Phil.
In that case a socket a couple of Uj's and extensions from the other side of the bike
If you undo the bolt above it , It has a captive nut, you just have to have a long extension .you will probably have to undo the mudguard bolts as well ,because the captive nut will stop you pulling the chain guard out
Having followed this thread and looked at the B40 Parts book I can see the confusion and why my solution may not be viable in your situation. I did not have a captive nut on the inside of the chainguard just a quarter inch clearance hole through the chainguard, so I had to be able to hold both the head of the bolt and the nut to tighten it up. Don't know why it should be different as when I got the bike it was very original and unmolested so presumably the chainguard was an original factory fitted part. It was very early model - manufactured December 1960 so maybe they changed the design to something easier to work on in later years. If yours is a captive nut it will be easier to remove the bolt into the chainguard rather then the one into the swinging arm.
Bernie, I was just wondering if you got time to do this yet? Phil.
Captive nut should be on the inside of the chain guard, if it doesn't have one weld one in place, chain guard can be removed with care without taking out back wheel or mudguard, bracket stays fixed to the swinging arm. HTH
Regards TTJohn
I eventually managed to undo the chainguard, but can't actually remove it without removing the back wheel and/or (not sure) mudguard. But anyway I have been able to move the chainguard enough to know that I've been wasting my time: the reason I wanted to remove it was to enable me to see the inboard side of the hole where the alternator wires leave the primary chaincase (looking to identify the source of a leak), but I still can't see it even when the guard isn't in the way. So I might as well fix the guard in place again. Sounds simple, but isn't. As I feared, refixing is even more tricky than removing. I have a loose chainguard, an L bracket and two hex-head screws to get in place in a very tight space. I think it would be much easier with the mudguard off. Remember I'm a novice: is the rear mudguard easy to remove? Thanks again for your help so far. Phil.
Hi Phil, only just seen your post from Jan - I haven't had a look at this yet - it's been too wet and cold to get out in the workshop but I will be attempting to fit the chainguard when the weather warms up a bit. I think that if you can get the bike on a ramp with clearance under the rear wheel the it shouldn't be too difficult to remove the seat and the rear wheel which should expose the nuts and bolts that hold the rear mudguard in place. Mine has only recently been rebuilt so I'll probably do that to fix the chainguard as I know that the threads are clean and so it shouldn't be difficult to strip down.
Cheers,
Bernie
Thanks Bernie. I don't have a ramp but hopefully a piece of wood under the main stand will raise the rear wheel an inch or two off the ground and hopefully that will be enough for me to take the wheel off, then the mudguard off. Anyway, we'll see. I'm learning slowly as I go along. Phil
Taking the rear wheel off, I obviously need to disconnect the speedo. I've undone the hex on the front of the speedo gearbox. Then what do I do? Phil.
Phil,
have you considered using a mirror to try and spot the leak?
Roger
It has crossed my mind to use a mirror. Maybe I should get one.
Re the oil leak. The hole where the alternator wire exits the primary chaincase should have a rubber grommet on it. They usually disintegrate over time. If the bike has been apart it is possible that a new grommet was not used - they are an absolute pain to fit. If there is no grommet it will leak oil.
The B 40 also has a "chain oiler" built into the rearmost primary chaincase bolt. The nut on the inside has a has a brass body with a small pipe coming off it which is meant to drip oil on to the chain. There should be a fibre washer between the nut and the primary chaincase, if not it will leak. I found that to control the flow of oil to a minor drip just enough to oil the chain I had to squeeze the tube almost closed otherwise it runs out much too fast - giving the impression of a serious oil leak.
There is a grommet but I wonder if it might be leaking. Some time ago a dob of silicone on it appeared to reduce - but not completely stop - the leak. I'd like to renew it but, as you say, that would be a pain. I looked into the chain oiler issue ages ago - can't rember details but was fairly sure that wasn't the problem.
Hi,
Sort of arrived at this thread due to my own issues. A couple of weekends ago when it was peeing down, I started to finish off re installing my head as I'd had it off for an overhaul. I thought I'd polish up the oil feed pipe to the rockers. All I needed to do was disconnect it from behind the oil tank but couldn't get to it. Took the side panel off and the frame behind it.
Still no joy so to cut a long I then proceeded to remove the battery, central cover with switch and oil tank and finally disconnected it. This gave me clear access to the chainguard and the fact it wasn't secured at the front bracket. I also decided it was a good opportunity for a clean up.
Couldn't get the chain guard off so then removed the rear wheel. Got everything off eventually. Stripped the rear wheel. Rubbed down and sprayed both centres and polished up the aluminium which had a few gouges in it. Also stripped and clean the rear brake shoes etc.
The front of the chainguard wasn't secured as the bracket was too short and there was a hole in the chainguard as Pete A10 said. Mine also is a December 1960. Perhaps they were having a Christmas P*ss up and forgot a few.
Anyway, made a new bracket and put it all back together this afternoon as it was weekend raining again after a hot week. Without everything else in the way access was easy. Again as Pete said, the chainguard must be the first thing on the bike when they start to build it. No wonder it caused so much consternation to others. Just got to clean up the oil feed pipe and then reassemble the centre panel etc. back where I was a few weeks ago.
Well done Rick, you've been busy! Phil