Bsa m21

[unstuck]

Dunno if it has been posted before, But I enjoyed it........http://www.ozebook.com/mcnews/bsam21/bsam21.htm So there it is.

[Akzle]

Dunno if it has been posted before, But I enjoyed it........http://www.ozebook.com/mcnews/bsam21/bsam21.htm
........So there it is.

fixed your shit HTML.

tempura prawns. and octopus with mayo.

[AllanB]

Your link did not work so I found one I liked.

http://hellonwheelskustom.blogspot.c...2/bsa-m21.html

[unstuck]

fixed your shit HTML.

tempura prawns. and octopus with mayo.

My one works fine thank you.

[unstuck]

Your link did not work so I found one I liked.

Cool.

[Motu]

I had an M20 - bought it in parts, and rebuilt the engine first as it interested me. Put in a new piston and mains, had some valve guides made. My B31 engine started a bit of a bigend rattle...it would last for ages like that...but put the M20 in the frame instead. The bike was actually a '54 A10 that I converted into a B31, seeing as the M20/21 uses almost the same bottom end, it's almost a bolt in. The B31/33 has a double ball on the drive side and single on the timing side, the M20 has double balls on the timing side...so is a little wider.

Going to a 425 lb bike with 13 HP completely altered my riding style, one I still use today. With that sort of power/weight ratio you NEVER BACK OFF - it takes so long to build momentum, you do your utmost to never lose it. I love low powered bikes. I'd been riding B31's and B33's with high comp pistons and Goldstar cams for years, starting the M20 with 5:1 compression was pretty easy, even without the valve lifter. I managed to get a 70mph top speed out of it...I may have fiddled with the gearing to get that.

I did get hold of an incomplete M21 engine, but it was the early 85x105 engine, and everything was different. So I started building a long stroke 600 OHV engine, putting B31 mainshafts into the M21 flywheels with a B33 top end. I never finished it.

Here's the bike, it was always in a state of change. There were 17 welds in that segmented front pipe. I'm using a 26mm Concentric there, but also used a Monoblock, a Mikuni and a Type 6, which had the float chamber well out on the right. Some used a horizontal Type 6, but I never found one to use.

This was the bike BSA should've built - the swingarm M20.