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I signed up cuz of an inspiring thread by Swan and this seems a perfect place for me to learn how to build my first cafe racer..
Where I am we have very little resources and tools available. There is hardly anyone with knowledge of old brit bikes so its going to be a steep learning curve for me.
I found myself a 1956 BSA B31..that in itself was a major achievement in a country were 70/125cc prevail and old bikes have either been exported or melted down!
The bike looked in ok condition and ran rough..the kick slips..japanese carb..no clocks but otherwise complete..I don't have any books so I've just been using online resources like the BSA service sheets and forums to find answers.
The idea is to transform this B31 from standard to a cafe racer like in the pics below:
thanks Sonreir..and i think i did bite off more than i can chew..
i was hoping to that it was only going to be cosmetic but its not looking that way..
i'm already struggling to remove the engine as bolts have bent when nuts couldn't be found..
current problems..
1) rear wheel won't come off as one of the sprocket nuts attached to the QD hub is rounded off and there is no way to get a socket around it.
2) the engine plate bolts have been bent so will have to be grounded off
3) and I'm missing some vital fork parts..they were just plain missing.. :-[
this is one of the engine plate bolts...bent and in a place where i can't get a the grinder in..
i tried straightening it but there isn't enough space to use a lever..any ideas?
I think I have information on B31, my father loved the things. (it's possible my brother has everything though?)
The QD rear wheel is common to BSA of that period, I'm not sure what your tying to remove?
You have release oil down axle shaft?
Slower method to get bent over bolts out, wrap tape around a 12" hacksaw blade, make sure teeth are cutting when you pull.
It's possible to flex blade and get it into a position where it will cut.
It will only take a minute or so to cut off flush
Even though you have bike, it probably isn't the easiest thing to work on without a full toolkit and manual.
Get on to the BSA owners club site, there is going to be a lot of information you can get from there
That bikes is so close to being complete, albeit rusty, that it might be worth a lot more restored.
Craftsman sells a set of nut removers. They are like an inside out E-Z out i.e. they look like a socket but inside are a set of spiral teeth to bite into the rounded off nut. You can probably get them on line.
Use lots of WD40 or local equivalent and be patient. Heat helps. Get a Propane burner/torch with a fine tip/nozzle.
All the bolts are BSF or Cycle threads so you need Whitworth/BSF wrenches and sockets.
They are actually not bad bikes - slow and ponderous but not too hard to make them go a little better and with a swept back pipe and Goldie silencer they look and sound good too. Tanks are mounted with a center bolt so most aftermarket tanks don't fit too well. I had a fiberglass tank on my 350 Goldie shaped somewhat like a Spitfire tank. They are still available I believe.
Magdyno can be a PIA but parts are available and they are reliable enough though they don't make a lot of power. You can upgrade with an ALTON dynamo from France (advertised in Classic Bike).
teazer, it does look fairly complete but over its long history its been butchered..i will post pics as the thread continues of each of the old bodged jobs and i hope how I fix it..(with everyone's help!)..i did think about restoring it to original but i have found a few others that i am keen to restore properly once i've cut my teeth on this one..(and the others won't be daily ride) Thanks for the tips guys..i used wd40 and tried the vice grips and hammer..it didn't work so i've had to resort to a chisel! The nut is damaged now (as are several other nuts done by the previous owner) and I doubt I can get a replacement so I'm thinking of repairing them all. Any ideas?
From the BSA service sheets I learnt that to remove the QD hub you need to leave the left hand axle nut on..unscrew the four bolts that attach the sprocket to the hub and then undo the right hand axle nut and pull it out.. the sprocket/chain/cover etc remain in place. so the beast is now on its belly...
go mama! for me this particular B31 is prime for a cafe racer conversion..I have another B31 which is in far better condition albeit with BMW stickers! this second one was also an ex-police motorcycle..i have a few others which i'll post about soon..
and honestly I do want a retro cafe racer..it's what i always wanted.. 8)
Would probably be best to do it as a 'period cafe' or a 'resto-mod'
That way you won't be cutting up frame and future owner could restore to original if they wanted (Unlike Honda 350, etc, it's not like millions of them were made, probably not even 100,000?)
crazypj..i don't intend to chop of modify the frame at all.
all original parts (like the mudguards, oil tank, tool box etc) will stay in my garage..
I intend to make it into a cafe racer as posted in my first post..seat, tank, oil tank, handle bars etc..
but before I can get there..the mechanics of the bike are in very poor condition and i need to fix them up.
I got the clutch apart today..when I took the cover off I was shocked to see the condition of the nut! the bearings were shot to pieces..and there is damage caused by the gearbox shaft..overall the clutch is bug*ered :-X
You need a special puller to get the center off shaft.
With puller it's really easy to remove, without correct puller, you will break center piece.
The busted cage shouldn't be too much of a problem as ball bearings don't mover around much until you pull clutch in, normally everything spins as a single unit.
Are the transmission bearings OK?
crazypj i'm not sure which shaft you are referring to..is it the gearbox one?
i'm not taking the gearbox and engine apart at the moment..i need to build up a mount for the engine first..
then i plan to take a sneak peak inside the engine (and gearbox) and order up sum replacement bits (if needed) definitely new gaskets as it leaks bad (both engine and gearbox)
so i've managed to get the bike stripped to the bone minus remove the swing arm which are notoriously difficult to remove especially with the hollow shaft.
this also creates a complicated issue of where to fit any rearsets..let me try and explain..on a normal B31 with a QD full width hub the brake pedal is fitted to a hollow shaft which in turn holds the swing arm. ideally you want to place the rear sets just below the swingarm axle but that won't work as the brake rotating point will be just above it..i've studied many other B31 / A7 and A10 cafe racers and realised that everyone has there own take on it. i'm going with below...what do you guys think?
1) Frame mods (rearsets)
2) Fabricate Oil Tank (need ideas)
3) Fabricate Seat unit (matchless G45 style integrated mudguard)
4) Figure out what to do with front yokes (clubmans or clip ons)
5) Fab up air scoop for the front brake
6) Drill holes in everything
7) Send off for Power coating
Yeah, when you need to remove main shaft you need to remove clutch center boss first.
If you have two B31's it will be worthwhile getting the correct tool and much cheaper than sourcing a new one.
I've seen a lot of them destroyed over the years when people tried to use 2 or 3 leg pullers or a chisel (one guy actually smashed the rear off primary chain case rather than spend money on puller : )
Just a crazy idea but why not make a simple bolt type mount in much the same place as a Goldie with that frame. Sleeve nut and piece of strap should do it and bolt the peg straight in there.
I know the Goldie had a more complex arrangement in that the peg was like a short version of the regular peg/mount.
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