B44 / B50 kickstart quadrant

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craigacc
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B44 / B50 kickstart quadrant

Post by craigacc »

Hello again all.

The 3/4 kickstart quadrant for various seems quite hard to come by now. But B50 type seems to be available.

I have a ‘68 B44 motor which lacks a kickstart quadrant. Can I fit a B50 type.

I’m aware I’d need the B50 K/S ratchet parts as well, but aside from that, what issues/work need to be thought about or done to fit a B50 quadrant to a B44 motor?

I’ve seen some other posts on this topic, but none that give a paint it by numbers guide for this modification. Ie, is the engine outer cover different, is the gearbox main shaft for the B50 different, is the B50 quadrant K/S shaft shorter/longer etc, does the step an the B50 quadrant matter, what part numbers to look for or avoid ( and why) and so on.

The Rupert R book has been some help, but suggests the ratchet mechanism is the only other change needed, but a BSA service sheet reprinted later in the book suggests the K/S shaft itself is shorter, which would suggest the outer engine cover would be different.

I apologise in advance for my ignorance.

Craig.
Triumph T25T 1971.
Ongoing B40 and B44 engine projects. Plus several other British Motorcycles
Cornwall, UK.
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Re: B44 / B50 kickstart quadrant

Post by minetymenace »

Basically the ratchet mechanism is turned round, there are two gearbox main shafts, one with long splines that will take either ratchet, one with short, that won't. Can't remember which is which, I think the outer covers are the same. No doubt someone will correct me if I'm wrong...
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craigacc
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Re: B44 / B50 kickstart quadrant

Post by craigacc »

Hi again,
Had to leave this for a couple of weeks, but on it again.

I went right through the parts books and only one mainshaft is listed for all B44 models 40-3254. The B50 appears to have just had one as well 57-4344.

So is the long splined shaft mentioned actually a B50 one, or a B44 one? Would be great if anyone could advise.

1968-on B44/B25/T25 kickstart ratchets/shafts seem to be completely unavailable at the moment, but B50 ones are about. But I don't want to spend on a B50 set up unless I know it can be made to work.

Thanks,

Craig.
Triumph T25T 1971.
Ongoing B40 and B44 engine projects. Plus several other British Motorcycles
Cornwall, UK.
craigacc
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Re: B44 / B50 kickstart quadrant

Post by craigacc »

Sorry, not ratchet, quadrants
Triumph T25T 1971.
Ongoing B40 and B44 engine projects. Plus several other British Motorcycles
Cornwall, UK.
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koncretekid
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Re: B44 / B50 kickstart quadrant

Post by koncretekid »

B50 mainshaft has the shorter splines but cannot be used in B44 without also changing the inner timing cover, or possibly machining the inner cover to accommodate the B50 kick start quadrant which is longer.

I was told by Ed V. that the B44 ones got chipped, as well as the B44 ratchet parts because the weight of the kick start arm caused it to rotate downward when coming off a jump which caused the quadrant to engage the ratchet and hence damaged both parts. And a lot of the B44's were used in scrambling (as motocross was called back then) as well as enduros.
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Re: B44 / B50 kickstart quadrant

Post by Momus »

Another one of the ways BSA tried to kill their riders.
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craigacc
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Re: B44 / B50 kickstart quadrant

Post by craigacc »

Thanks, interesting info and history. So I suppose I’m back to my main query - can I fit a B50 kickstart quadrant into my B44 (which has a B44 mainshaft) and simply turn the ratchet mechanism the other way round?
Triumph T25T 1971.
Ongoing B40 and B44 engine projects. Plus several other British Motorcycles
Cornwall, UK.
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Re: B44 / B50 kickstart quadrant

Post by minetymenace »

I think you can fit the quadrant, but the ratchet is the other way round, so you will need a new ratchet and pinion.
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koncretekid
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Re: B44 / B50 kickstart quadrant

Post by koncretekid »

craigacc wrote: Sun May 24, 2020 5:33 pm Thanks, interesting info and history. So I suppose I’m back to my main query - can I fit a B50 kickstart quadrant into my B44 (which has a B44 mainshaft) and simply turn the ratchet mechanism the other way round?
The B50 quadrant is longer so the recess in the inner timing cover is machined deeper (flush with the surface of the mainshaft bearing surface) to accommodate.
inner timing covers
inner timing covers
It seems you could make the conversion by machining the B44 timing cover. Note you will lose the slight recess for the dowel pin snapring (circlip) that anchors the kick start return spring, but BSA just pressed the dowel pin in further on the B50 until the snapring seats on the new surface. I believe that the cover I'm calling B50 in my photo may actually be late model B25/TR25 and not the B50. You can still use the B44 mainshaft. This actually seem like a good idea, as you say, good B44 quadrants and kick start ratchet gears are more scarce than those for the B50.

Tom
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Re: B44 / B50 kickstart quadrant

Post by minetymenace »

Thank you koncretekid, that comparison image says it all!

Thought I'd put this up as well for completeness (shows difference in the ratchets):
Kicker.jpg
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Re: B44 / B50 kickstart quadrant

Post by craigacc »

That's excellent - really helpful thanks!
Triumph T25T 1971.
Ongoing B40 and B44 engine projects. Plus several other British Motorcycles
Cornwall, UK.
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