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BSA B50 short kicker spline mainshaft year?
#625012 11/09/15 11:18 pm
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I goy a b50 gear set out of a buddy's motor today and it has the short splines section on the mainshaft kicker side. I looked at the parts book of '71 and '70 and it shows the '69 style MS with long spline section. When did the mainshafts change? I need to source the gears for kicker that fit as the spares I have from '69 do not seem to fit even reversed as on my MX way back. Any ideas?
Steve


The 441, most versatile BSA of the 60's
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Re: BSA B50 short kicker spline mainshaft year?
441/R3cafeSteve #625018 11/10/15 12:17 am
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Steve,

The B50s had a redesigned kick quad. With the redesign they flipped the ratchet and ratchet pinion on the main shaft. The teeth point in the opposite direction from the B44s. The ratchet mechanism is also held with a different washer. The internal toothed washer is no longer used.

In 1971 BSA shortened the grooves cut into the ratchet end of the mainshaft but that makes no difference if you use an earlier mainshaft (40-3254) on a B50 with the flipped ratchet mechanism.

I don't think it will make any difference going the other way either, a B50 mainshaft into a B44. You should be able to use the B44 ratchet mechanism and kick quad with the B50 mainshaft and gear cluster. I'll admit I haven't tried it so there may be something I am not picturing. I guess I'll have to go out and compare them tomorrow. What excatly doesn't work with your B50 cluster? Are you talking about the ratchet pinion and ratchet? The B50 quad will not work with the B44 ratchet, nor visa versa.

By the way the parts book for the 1971 B50 has the wrong pictures of the mainshaft and ratchet assembly. They use the B44 illustration (wrong) but do use the correct updated part numbers for the parts not pictured.

Peter



check out: www.bsaunitsingles.com
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Re: BSA B50 short kicker spline mainshaft year?
Peter Quick #625019 11/10/15 12:48 am
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Thanks Peter, I'll take a kicker ratchet set for the B50 shaft if you find a good set, I did notice the parts #'s are different from '69 441. The movement on short spline is lacking play with b44 ratchet set. I will email you. The illustration must have caused a few confused wrenchers over the years! LOL!
Steve
-Have a couple of 441 b25 hybrids to build this winter.


The 441, most versatile BSA of the 60's
Re: BSA B50 short kicker spline mainshaft year?
441/R3cafeSteve #625088 11/10/15 12:26 pm
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Originally Posted by 441/R3cafeSteve
Thanks Peter, I'll take a kicker ratchet set for the B50 shaft if you find a good set, I did notice the parts #'s are different from '69 441. The movement on short spline is lacking play with b44 ratchet set. I will email you. The illustration must have caused a few confused wrenchers over the years! LOL!
Steve
-Have a couple of 441 b25 hybrids to build this winter.


The B50 kickstart quadrant won't work on a B44/B25 because the inner timing cover is machined differently to accept the kickstart quadrant. You're better off just getting a B44/B25 main shaft and using your existing kickstart components.

The B44/B25 inner timing cover could be modified but I feel it is just not worth the time and effort.

Peter Joe

Re: BSA B50 short kicker spline mainshaft year?
Peter_Joe #625163 11/10/15 10:00 pm
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Hi Peter_joe, got that covered LOL! I have a couple of b50 inners without the quadrant boss so no need to modify a b44. The outer components do have different # in books so I will try and source the b50 pinion and gear. Thanks for the heads up that is an important factor.
Steve


The 441, most versatile BSA of the 60's
Re: BSA B50 short kicker spline mainshaft year?
441/R3cafeSteve #625179 11/10/15 11:29 pm
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I checked various model inner timing covers and B50 vs B44 mainshafts. I was correct that you can use a B44 mainshaft on a B50 but it doesn't work the other way around. The ratchet on a B44 slides on the shaft first and needs to go all the way down to the bearing. On the B50 the opposite. The ratchet goes on last so the slots don't need to be so long. So the length of slots question is resolved (for me).

So with a B50 mainshaft you do need to use a B50 inner timing cover and the B50 kick quad and ratchet assembly. The ratchet pinion on all unit singles takes a beating and I don't come across all that many used ones worth recycling. I also come across way fewer B50 motors that I want to part out. So no used B50 ratchet pinions or used ratchets on hand.

I do have new B50 ratchets and pinions along with a whole bunch of new B50 kick quads I got in recently. In case you really want to start spending money.

Peter



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Re: BSA B50 short kicker spline mainshaft year?
Peter Quick #625368 11/11/15 9:24 pm
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Steve,
The 72 parts book corrects most if not all of the errors in the 71 book. I learned about the same issues you have when I did my B50 and the kick start ratchet assembly was knackered. I had only a 71 parts book.. If you need a scan of the 72 book give me a private e-mail.

Mr Mike

Re: BSA B50 short kicker spline mainshaft year?
Mr Mike #625524 11/12/15 10:42 pm
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Looked at '73 book and it has right illustration of mainshaft '72 I saw has old drawing still. I wonder if the guy that insisted they correct it in the last year thought they would be making more B50's in '74. I am resisting the urge to make a fake board track street racer out of a b25 frame but the lines just don't work without chopping and cutting so a mock DBD cafe may be my goal. A Delhi Goldstar tank at $400. US is about a thousand canadian! I may have to settle for a damaged 4gal super rocket tank.
Steve


The 441, most versatile BSA of the 60's

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