BSA M33 Telescopic fork

[ohegle]

I just bought a 1952 BSA M33 who's been civilized, and I plan on bringing it back to military. But I have one question: I have cleaned out the front fork and fitted new seals, but it is not dampening much, only just before it hits bottom, can you feel the dampening of the oil. Is this normal? Or do I put more oil into it? The book says 1/4 pint, so I put that inn, but I see Draganfly motors says 1/3 pint.... I have used SAE10 oil, should I use SAE20 or 30 perhaps? Any thoughts?

 

Oyvind

[Ron]

Maybe your springs are weak? Shouldn't you use proper fork oil? If you have the correct book for your model, I would go with that.

 

Is this a Norwegian Army bike? I'm pretty sure the British Army didn't use them. Ron

[ohegle]

No, the springs are not the problem, it bounces up quick enough, actually to quick. I have used fork oil SAE 10, the highest SAE fork oil the shop had, but from what I can find in manuals, it should be SAE 20.

I have now put mineral SAE 30 oil in the forks, and 200 ml, not 140 as the manual says, and it is better, but still the girder fork on my Ariel feels better.

I will leave it by now, and try it on the road, as soon as I have rebuildt the engine and gearbox ;-)

 

Oyvind

 

From what I have been told, the bike was used by the norwegian airforce. I have no records to prove it, but I keep looking

[79x100]

A good set of girders is often nicer than a poor set of teles.

 

I don't know 1950s BSAs, but wouldn't the M33 only have one-way (rebound) damping ? I seem to recall lots of talk about aftermarket 2-way dampers for Gold Stars etc.

 

Extra oil, if it's above the dampers, won't make much difference but any wear on damper rods etc. will impair the rebound damping. I'd assume that most people at the time just put engine oil in.

 

The BSA Owners Club (or the VMCC) should be able to tell you who the machine was delivered to (certainly if it was part of a Government contract)