Trick 1973 Yamaha 360 MX

[GMC]

Oh, the article was from 72 cycle world.

This is my replica arm of the B & S, I don't think I would want to replicate Marc's arm though, I would have to employ a first year apprentice to be able to design & make gussets like that

[mx250]

How much?

[GMC]

Bout a grand to build something like that, which I guess is why I have only built the one.
There was a lot of maching in those end plates which added to the "normal" cost of a swingarm.

I do have a spare set of those endplates though.

[yzhilly]

Wow that is Smick .

[motomaniac]

Wow that is Smick .

Yer nice job Mr GMC.

btw the PDI arm wouldn't be that hard as the end section is just a big plate with holes in it and a slot cut out to fit over the tube section at the front.

[Marc.com]

Oh, the article was from 72 cycle world.

This is my replica arm of the B & S, I don't think I would want to replicate Marc's arm though, I would have to employ a first year apprentice to be able to design & make gussets like that

Ah but my arm allows you to adjust wheel clearances or alternatively use shock absorbers ranging from 12" to 17" in length.

[firko]

PDI arm wouldn't be that hard as the end section is just a big plate with holes in it and a slot cut out to fit over the tube section at the front.

The Hard part is replicating the cast pivot area as seen below.

Ah but my arm allows you to adjust wheel clearances or alternatively use shock absorbers ranging from 12" to 17" in length.

Marc, if you're talking about the swingarm on the MX250, you're limited by the  pre 75 rules of just about every country that had vintage MX which stipulate that you must use the original suspension mounting points and use shocks no longer than 1" over the original length. That cancels out the squillion shock mounts and allows you to remove the ugly fluckers. Believe me, your bike will look so much better without the gussets. B&S/PDI swingarms are quite attractive without the home made additions.

[motomaniac]

PDI arm wouldn't be that hard as the end section is just a big plate with holes in it and a slot cut out to fit over the tube section at the front.

The Hard part is replicating the cast pivot area as seen below.

Ah but my arm allows you to adjust wheel clearances or alternatively use shock absorbers ranging from 12" to 17" in length.

Marc, if you're talking about the swingarm on the MX250, you're limited by the  pre 75 rules of just about every country that had vintage MX which stipulate that you must use the original suspension mounting points and use shocks no longer than 1" over the original length. That cancels out the squillion shock mounts and allows you to remove the ugly fluckers. Believe me, your bike will look so much better without the gussets. B&S/PDI swingarms are quite attractive without the home made additions.

Nar .I think he was talking about all the holes in his swingarm - plenty of options there.

[Marc.com]

. That cancels out the squillion shock mounts and allows you to remove the ugly fluckers. Believe me, your bike will look so much better without the gussets. B&S/PDI swingarms are quite attractive without the home made additions.

I don't think they are home made at all, oh no, I think they are original and your swingarm has been hacked only leaving the front and rear as a pair of lugs. I would not desecrate my swingarm. It would be like pissing in the Sistine Chappel to hack away at art.

Now happily the Japanese have not yet taken leave of their senses and my bike is very welcome along with me. 

[Davey Crocket]

Hey Marc, do you see much trick stuff for sale in Japland?. You would think that they would have a fair bit, I'm sure  Mr Yamamato san must have snuck stuff away over the years? or the factories have "extras" hiden away in some dis-used wharehouse that they have forgotten about?. From what I can gather by the mid to late 70's they stopped crushing them, cutting them up or dumping them into the North sea.

[Marc.com]

Set of works SR (works kawasaki) Kayabas came up the other day, but the USA is probably better place to shop with the Yen so high.

[mx250]

.... the guy wanted a B & S replica arm to build the same project.

Do you know if the guy completed the project?

I saw the original of that article 'back in the day' and it sparked my interest in lightweight as a performance enhancer.  It's been in the back of my mind to do something similar even if it was to find out what it does to the performance. (The Monty conical hub/wheel looks like it will fit the MX swinger and is about 2kg lighter (IIRC). Hmmmm, thinking, thinking, thinking ).

[Marc.com]

Believe me, your bike will look so much better without the gussets. B&S/PDI swingarms are quite attractive without the home made additions.

Actually believe it or not Firko I have 2 of these multi adjustment swingers, must have been production item. Imagine if you had one on an MX Harley, you could move them up to hill climb on Sunday and move em back for bike night on Monday

[GMC]

.... the guy wanted a B & S replica arm to build the same project.

Do you know if the guy completed the project?

I think so, like many of us he had a few projects on the go. Haven't heard much of him for quite a few years now. I think I built that arm about 5-7 years ago.

[Marc.com]

Heh Geoff I will swap you two genuine ones for your replica