1950? 500cc BSA project

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wayne z

Active Member
Dec 5, 2010
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I was referring to thr gearbox shafts, and the width of the internal gears, to get a feel fow how hefty the parts are.
 

rustycase

Gutter Rider
May 26, 2011
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i guess i'll put my 2cents in.
that clutch will not hold that motor.
may not even be able to start it.

if the hook-up was resolved, then the tranny would quickly show its limitations.

sry 2 say
rc
 

harry76

Well-Known Member
Apr 16, 2011
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Wayne Z, i know you asked me to measure the gears but i noticed the size difference in the engine sprocket and the gearbox sprocket. The engine sprocket is 7.4mm wide while the gearbox sprocket is only 4.6mm...... before i go pulling the box apart i thought id ask your thoughts on that. Do you think that makes it a little small and probably not usable. Even if i were to use this box id need to modify sprockets....... maybe i need to just wait and see if a larger gearbox comes up on EBay that is in my budget.

Just for a comparison heres one of the 160cc Victa engines i mentioned earlier that would probably work with the box





 

wayne z

Active Member
Dec 5, 2010
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After seeing the 500 and the tranny together, I would say that the tranny way to small to try, heck, the clutch sprocket isn't much bigger than the engine's drive sprocket.


You could also use an old Harley tranny and clutch. I see servicable ones sometimes for 500 bux localy. Might find one cheaper if yer good at scrounging.
 

fasteddy

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Feb 13, 2009
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Looks like the gearbox that they put on the Whizzers that they converted

Yes. Harley has gone to belt drives but the pulleys and belt have teeth in them.

Another thing to think about is the gear ratios. Like having a pulley too large or small for your build. The engineers built a big gearbox for a reason. It needed it.
They were not tossing company profits out the window just so they could have a fancy looking rig. There was a need for bigger, wider gears, heavier bearings running in a larger oil bath to lubricate the gearbox and keep it cool.

Is it possible to find a frame that this motor will fit? Don't know if there are any later frames in the 50's or 60's that will allow you to get a little later look as was mentioned as well as a vin# that will allow you to put it on the road if you wish. I believe you need a frame that allows you to have the two piece unit now that I think about it. Don't know if you can change a one piece unit frame to make it fit. This is a good reason to join a club that collects these. They will have the answers and maybe parts.
Wonder if you found a gearbox for it that it did have and could hide the gearbox and still allow it to cool as you ride it.

Steve.
 

wayne z

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Dec 5, 2010
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The Victa ix cool too. Looks like a perfect match for the tranny. It looks like you could rotate the head 90 deg to orient the fins with the airflow.

I'll trade you my 1898 Columbia chainless bike for the 500, shipping too :~)
 

fasteddy

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Feb 13, 2009
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Since the BSA is bigger it has bigger cool but the Victa is right there with it in the cool department in my book.
Since your closing in on your cooler season there may be more on ebay or does it get miserable enough there for people not to ride? Just thinking that someone may have moved some parts so much that they just put it on ebay to get it out of the way.

Steve.
 

harry76

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Apr 16, 2011
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Fasteddy, im not really interested in trying to restore an M20, im not that much of a fan. In fact (sorry if this offends some owners lol) i find that style of bike (similar to Triumphs etc) with the large seats quite ugly. Im not a fan of those bikes from that era unless it is to turn them into a bobber style bike.

The only reason i bought this engine is it was cheap and i liked how it had a seperate gearbox and rounded bottom end i thought would be perfect for a droploop frame, i really like how the engine looks from the drive/sprocket side, very round and looks very similar to the single cylinder boardtrackers.

If i cant find a small seperate gearbox up to the job, or a way to start the bike with a direct belt drive setup Maybe i should clean the engine up a little and pass it on to someone who would appreciate it more. I posted my engine on a BSA site and they nearly died when i said i payed under $200 for it, so im sure i wont lose out.

And the gearbox wont go to waste as i have plenty of engines to suit it. In fact the guy i bought this one off has another Albion (that one is definitely Albion as it is stamped on it) very cheaply but it doesnt have a clutch, i was wondering if i did the same setup as my Villiers build with handclutch, but would then have gears.
 

harry76

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Apr 16, 2011
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Our cool season? Wed call it a cool season but youd probably think its summer. 15 degrees celcius or 59 degrees faranheit is our winter. You can ride all year really
 

harry76

Well-Known Member
Apr 16, 2011
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The Victa ix cool too. Looks like a perfect match for the tranny. It looks like you could rotate the head 90 deg to orient the fins with the airflow.

I'll trade you my 1898 Columbia chainless bike for the 500, shipping too :~)
Wayne Z, that Victa is cool, 160cc and fairly cheap here in OZ.

Ive had it for some time. I bought one after seeing the bike that got me into this hobby.

Theres a bulder here in OZ "Hillbilly" (ive tried contacting this guy but cant) that used the smaller 125cc version, added electronic ignition, removed the flywheel i think (will the engine still run properly with no flywheel, i know it has electronic ignition, but still) and built a faux bottom end.

This bike is out of this world if you ask me, if you havent seen it i suggest you sit down LOL

http://bikerodnkustom4.homestead.com/gallery403.html
 

fasteddy

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Feb 13, 2009
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Yes summer here on the coast is around 72F-76F.

Looked back at the posts I made and didn't see where I even hinted at a restoration. 8)
You need parts, clubs have parts. That sounds to me like a good deal. Clubs always have a few zanies that like to build outside the box and have. I'm thinking since your building outside the box they would a good source of ideas and the before mentioned parts you will need.

If you have plans re-engeneering the engineers, engineering you can't always get what you want. It's cost me tens of thousands of dollars over the years to find this out but I am enjoying watching you do it.

That's all. Carry on.

Steve.
 

harry76

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Apr 16, 2011
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Fasteddy, i may have misunderstood you, but you did say i should find a later model frame, and that was my point. They arent my thing and i couldnt build the bike id like from that platform.

Im not trying to re-engineer anything, just asking questions. I want the boardtrack look, if i cant achieve that im not really interested. As Wayne Z mentioned the size of a box can be determined by the amount of gears. Id be willing to have less gears even at the expense of ridability
 

harry76

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Apr 16, 2011
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After seeing the 500 and the tranny together, I would say that the tranny way to small to try, heck, the clutch sprocket isn't much bigger than the engine's drive sprocket.


You could also use an old Harley tranny and clutch. I see servicable ones sometimes for 500 bux localy. Might find one cheaper if yer good at scrounging.
Missed this post, i have been looking on EBay but obviously it may not be the best as they are all very expensive. Ill keep looking and see what comes up. Ive seen M20 boxes from England that dont seem too expensive but the postage is more then the cost of the box and a lot more then im willing to pay. Ill just see what comes up.

In the meantime i should move forward with this gearbox and 160cc Victa, parts are still readily available. I might go price the electronic igntion setup ive seen available for them.
 

harry76

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Apr 16, 2011
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Brisbane, Australia
I didnt actually mean ridability (why do you americans say drivability, you dont drive a bike lol) in that regards, sorry i should be more clear. I dont mind if i only has a low top speed if that makes sense. Sorry ive come off a night shift and a little foggy still.