1967 B-40 WD
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Paint scheme had to be something BSA- like, so the two- tone arrangement as used on sixties' competition machines was chosen. A shade of green - resembling the prewar BSA colour - and yellow and red as in the old BSA- logo looked like a perfect match to me.
Logo was cut using low-tack adhesive film - as used for airbrush work on paper.
Light sanding between layers made for a smooth transition.
Paint scheme had to be something BSA- like, so the two- tone arrangement as used on sixties' competition machines was chosen. A shade of green - resembling the prewar BSA colour - and yellow and red as in the old BSA- logo looked like a perfect match to me.
Logo was cut using low-tack adhesive film - as used for airbrush work on paper.
Light sanding between layers made for a smooth transition.
Cutaway drawing of the early 343cc B40 Star Engine.
Meanwhile, the engine was completely dismantled as well.
Luckily, it was in fairly good condition. Valves, valve guides and piston rings obviously needed replacement, as did the small end bush.
Bore was standard and there was no sign of wear, so I made some wooden covers to protect the inside and put it in my blasting cabinet to clean of all rust and leftover paint. Then it was sprayed in Granville Cylinder Black.
Honing finished it of and after applying some oil in it, it was wrapped in some rags and paper until needed.
The cylinder head was damaged - someone obviously used a hammer instead of a mallet ( some people never learn ... ) - so it needed repair.
My longtime mate Rudi Verbist - well-known here in Belgium and beyond for his stand at autojumbles - gave me a box with leftover B40 parts - including a complete clutch, cylinder, rockerbox, various other small bits AND a damaged B40 head, so I could cut a suitable replacement fin.
Then the head was sent to a fellow classic bike enthusiast who did a nice job welding it.
The head I got from Rudi, also supplied me with some undamaged studs, since mine were bent and some had damaged threads...
Luckily, it was in fairly good condition. Valves, valve guides and piston rings obviously needed replacement, as did the small end bush.
Bore was standard and there was no sign of wear, so I made some wooden covers to protect the inside and put it in my blasting cabinet to clean of all rust and leftover paint. Then it was sprayed in Granville Cylinder Black.
Honing finished it of and after applying some oil in it, it was wrapped in some rags and paper until needed.
The cylinder head was damaged - someone obviously used a hammer instead of a mallet ( some people never learn ... ) - so it needed repair.
My longtime mate Rudi Verbist - well-known here in Belgium and beyond for his stand at autojumbles - gave me a box with leftover B40 parts - including a complete clutch, cylinder, rockerbox, various other small bits AND a damaged B40 head, so I could cut a suitable replacement fin.
Then the head was sent to a fellow classic bike enthusiast who did a nice job welding it.
The head I got from Rudi, also supplied me with some undamaged studs, since mine were bent and some had damaged threads...
Above: a piece of fin was cut from the spare head I got and shaped to be a perfect fit, prior to welding.
After washing the head thoroughly with cellulose thinner to remove any oil and dirt, it was put in the blasting cabinet and bead blasted clean.
The head was then heated in an old electric oven that I use for that purpose only and the valve- guides nocked out.
The exhaust guide was very brittle and - even though I didn' t hit it hard - fell apart in small pieces , so I guess it had been pretty hot one day.
Now I know these engines have the tendency to burn valves if ridden hard, so maybe this had been the case ( the valve wasn' t burnt though )
Anyway, new guides were fitted ( guides in freezer, head in oven ) and the head was sent to another fellow enthusiast who has the proper tools to recut the seats.
He also reamed the guides.
The head was then heated in an old electric oven that I use for that purpose only and the valve- guides nocked out.
The exhaust guide was very brittle and - even though I didn' t hit it hard - fell apart in small pieces , so I guess it had been pretty hot one day.
Now I know these engines have the tendency to burn valves if ridden hard, so maybe this had been the case ( the valve wasn' t burnt though )
Anyway, new guides were fitted ( guides in freezer, head in oven ) and the head was sent to another fellow enthusiast who has the proper tools to recut the seats.
He also reamed the guides.
Above: The nearly finished cylinder head.
Thanks to some mates, total cost of refurbishment was only 60 €. Not too bad, isn' t it ?
Thanks to some mates, total cost of refurbishment was only 60 €. Not too bad, isn' t it ?
The engine was in a good condition, but needed thorough cleaning, some bushes and - of course - all new seals.
A nearby neighbour - keen classic motorcyclist and fine mechanic - Marc, has a workshop with lathe, milling machine and any other goodies you' d expect. He made new bronze bushes for the engine and new ( stainless steel ) wheel spindles, brake rod and other smaller items.
A nearby neighbour - keen classic motorcyclist and fine mechanic - Marc, has a workshop with lathe, milling machine and any other goodies you' d expect. He made new bronze bushes for the engine and new ( stainless steel ) wheel spindles, brake rod and other smaller items.
Above: the engine during reassembly.
Always nice to see were it came from when compared to the image on first page...
Always nice to see were it came from when compared to the image on first page...
The first B40 engine - basically a big-bore C15 engine - had a car type distributor- like arrangement that housed the contact breaker points. From 1965 onwards, this was replaced by side points, fitted directly to the camshaft.
The timing side crankshaft bush was replaced by a roller bearing as well and it received a far better gearbox than the rather weak one used before.
The chromium plated tunnel housing the pushrods in the earlier engine, was now an integral part of the cylinder casting.
The drawing at left and photo above clearly show some of the differences. ( have a look at the C15 pages for more images of the earlier engine )
The timing side crankshaft bush was replaced by a roller bearing as well and it received a far better gearbox than the rather weak one used before.
The chromium plated tunnel housing the pushrods in the earlier engine, was now an integral part of the cylinder casting.
The drawing at left and photo above clearly show some of the differences. ( have a look at the C15 pages for more images of the earlier engine )
The small teeth on valve lifter spindle and lever were gone and the lever was broken. In the box of bits I got from Rudi, was a badly damaged rockerbox ( with its rockers rusted solid... ) but the valve lifter was complete and intact. Lucky me again.
Picture above shows the cleaned and bead- blasted rockerbox during assembly.
Picture above shows the cleaned and bead- blasted rockerbox during assembly.
Primary drive was in good condition too, but I fitted rubber shock absorbers in the clutch ( none were fitted ) and new rollers.
Plates were as new and could be reused as were chain and sprocket wheels.
Plates were as new and could be reused as were chain and sprocket wheels.