-67 BSA WD B40 Mk1

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Jan 18, 2020
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Finished fixing most flaws I've found on an ex. danish military B40. PO seems to have little knowledge on how to set up an old british motorcycle.
It is a good looking well painted bike with a lot of dirt bike mods.
What I had to do to get it a decent runner.
Bad front brake. Loosen front axle, pull lever and retighten.
Lens on headlamp, the TOP mark pointing to the right.
Electric system total mess, total rewiring. A number of improvements over original.
Home made tank holding bolt fixings and wrong rubbers made the tank in metallic contact with frame.
The short saddle fastened so that I had to remove rear mudguard to get it off.
Much axial and radial play in swingarm. These machines have silentblocs like a Dommie. PO had not managed to tighten the swingarm
axle nut enough. So inside of silentbloc was free to rotate on the axle. Steel to steel without lubrication.
Solved with new axle and axial shims.
Adjusting ignition timing.
Loud popping rolling back twist grip. Found that the high level exhaust could be pushed into head another 1/4".
New bracket made. Also had to cut off an inch at rear end of exhaust pipe. Now silencer can be removed without first removing rear shock.
PO or someone before had fitted an old worn Monobloc from a -61 T110. And fitted a too long choke slide, now removed.
Also ignoring the fact that a bike intended for gravel roads should not be fitted with an open bellmouth.
Worst carb problem was that idle could not be adjusted without removing the battery.
Solved with relocating and making a new battery tray. Saved 6.6lbs.
Not to mention the mixture of Metric, UN, W and cycle threads.
Now quite enjoyable to ride, if you're not in a hurry.
 
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Joined
Sep 18, 2020
Messages
11
Country flag
Finished fixing most flaws I've found on an ex. danish military B40. PO seems to have little knowledge on how to set up an old british motorcycle.
It is a good looking well painted bike with a lot of dirt bike mods.
What I had to do to get it a decent runner.
Bad front brake. Loosen front axle, pull lever and retighten.
Lens on headlamp, the TOP mark pointing to the right.
Electric system total mess, total rewiring. A number of improvements over original.
Home made tank holding bolt fixings and wrong rubbers made the tank in metallic contact with frame.
The short saddle fastened so that I had to remove rear mudguard to get it off.
Much axial and radial play in swingarm. These machines have silentblocs like a Dommie. PO had not managed to tighten the swingarm
axle nut enough. So inside of silentbloc was free to rotate on the axle. Steel to steel without lubrication.
Solved with new axle and axial shims.
Adjusting ignition timing.
Loud popping rolling back twist grip. Found that the high level exhaust could be pushed into head another 1/4".
New bracket made. Also had to cut off an inch at rear end of exhaust pipe. Now silencer can be removed without first removing rear shock.
PO or someone before had fitted an old worn Monobloc from a -61 T110. And fitted a too long choke slide, now removed.
Also ignoring the fact that a bike intended for gravel roads should not be fitted with an open bellmouth.
Worst carb problem was that idle could not be adjusted without removing the battery.
Solved with relocating and making a new battery tray. Saved 6.6lbs.
Not to mention the mixture of Metric, UN, W and cycle threads.
Now quite enjoyable to ride, if you're not in a hurry.
I have one of those too. Now it will go to make room for Commando ;-)))))))
 
Joined
Jan 18, 2020
Messages
277
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As autumn arrived, the B40 had got quite a number of miles. Some work for the winter.
It wet sumps badly. Might be that the one way valve, BSA has after the pump leaks. Also got a new oil pump for it. And will fit a drain plug. Also will get a Concentric for it.
Has to play a little with the Victor Special too. But that's another story.
 
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Jan 18, 2020
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A little update on my BSAs. Last week finally got the Victor tested and approved for road use forever. Then proceeded servicing the B40 and had a test run. It started to spread clouds of blue smoke, much more than the twostroke RG racer we started after a crank change the same day. Will check next winter if it's only a broken ring or if a rebore is needed.
In case something happens with the Victor, I unexpectedly happened to buy another -70 Victor Special two days ago. Will try to find out which of them is best to ride. Never expected to have BSA twins.
 
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Mar 7, 2020
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Can't beat the simplicity of the one lunger.... or the torque that feels like it could climb walls....
Just not very long legged :-(
 
Joined
Jan 18, 2020
Messages
277
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Last Saturday finished the RDLC racer fork mod. Some other minor fixes too so now ready to race. After that me and my son took a trip on the Victors. After some 10 miles we changed bikes and went back. We could not figure out which was best. Only difference was one was easier to start.
One minor problem was that the hard to start one dripped petrol. Hopefully solved, fitting a new float and adjusting float level + fitting a new fibre washer.
If still fighting back when kicked, will check ignition timing and advance mechanism.
 
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