Twin shocks alloy swingarm

[Michel Dufayard]

Hello
This is a 250 cr 82 with an alloy swing arm ( Aprilia original I think ).
Does somebody has make this kind of changing on a hva twinshock ???
Others pics ???
Is there alloy swingarm after market for these bikes ???
Thanks
Michel

 

[ruwfo]

1980 Husky Aluminum swingarm in a box

Michel,

yes i have a 1980 Husky Aluminum swingarm in a box, bought it
off ebay, but never mounted it on any thing, i'll take so pictures
of it soon, got a vintage MX tomorrow .

John

 

[Leftcoast leftkicker]

All- yes there's a market (see Maico's) but they've got to be set up properly. Banana arms look cool but after initial experimentation most teams passed on them. Plus with the different shock mount positions (see swing arm length difference between CR, XC & WR models), year/frame (pre-80, 80-82, 83+ twin shock), rear brake drum (XC & WRs differ from CR) and mounting type (rubber grommets/bushings v. heim joints) it'd be a bear. I spoke with the guy who makes the Maico-Only arms and he's up for it but needs a CR bike as a jig (and I'm not leaving mine).

 

[Michel Dufayard]

Michel,

yes i have a 1980 Husky Aluminum swingarm in a box, bought it
off ebay, but never mounted it on any thing, i'll take so pictures
of it soon, got a vintage MX tomorrow .

John

Hello John
Would be happy to see one !
Thanks
Michel

 

[Michel Dufayard]

All- yes there's a market (see Maico's) but they've got to be set up properly. Banana arms look cool but after initial experimentation most teams passed on them. Plus with the different shock mount positions (see swing arm length difference between CR, XC & WR models), year/frame (pre-80, 80-82, 83+ twin shock), rear brake drum (XC & WRs differ from CR) and mounting type (rubber grommets/bushings v. heim joints) it'd be a bear. I spoke with the guy who makes the Maico-Only arms and he's up for it but needs a CR bike as a jig (and I'm not leaving mine).

Yes there's differences of lenght and of position shocks.
But I think that the design near the axle (axle through motor and swingarm) is the same.
In my mind, an alloy swingarm could be nice for 79 + models.
Not sure it would be nice for a 78- models.
Michel

 

[Michel Dufayard]

I have thought about putting a HVA monoshock alloy swingarm ( 85-88)
with spacers , but the right side is not symetric to the left side like on iron 80-84 models.So, I'm not sure that the shocks would be on the right place with the right angle.

 

[WestCoast]

"Pro Circuit" One-Off Special Rocket

I think "Pro Circuit" had a better idea.
If anyone knows where one is...I'd like to get some measurements -

 

[Michel Dufayard]

I think "Pro Circuit" had a better idea.
If anyone knows where one is...I'd like to get some measurements -

WOOAAAWWW !Niiiice ****************************************
Could you send me please,the pics in good quality on my email !
Thanks

 

[Leftcoast leftkicker]

I think PC used a Honda arm to make that proto-type

 

[Michel Dufayard]

Another HVA with an alloy swingarm !

 

[WestCoast]

Anyone ID this arm?

This was on eBay a few years back - Maybe someone here bought the bike? ... auction did not meet reserve price

 

[pcnsd]

The first swingarm in this series appears to be from a 1979 era RM/PE Suzuki. It is likely slightly longer than stock for this application. (May not be a big deal.) These have been adapted to many bikes over the years, very popular with the Yamaha TT500 guys.
The last swingarm shown above is a Profab swingarm. Great swingarms if you can find them, come with a dear price if the owner know's what he's got.

Regards,
PC

 

[Bryll]

The last one looks like a pre production version of the one Sten Lundin made for Bengt Åbergs HL500 bike.
I got one on my old Cheney-Yamaha (with some Husky parts too).
View attachment 1966
Took this picture when I just put the bike together again after almost 25 years in different boxes.

 

[Michel Dufayard]

The first swingarm in this series appears to be from a 1979 era RM/PE Suzuki. It is likely slightly longer than stock for this application. (May not be a big deal.) These have been adapted to many bikes over the years, very popular with the Yamaha TT500 guys.
The last swingarm shown above is a Profab swingarm. Great swingarms if you can find them, come with a dear price if the owner know's what he's got.

Regards,
PC

For the first swingarm, I've been told by Aprilia owners , that it was one part of these bikes. See the 2 pics.

 

[MAG250]

Don't know if these guys would make one.
The only one they offer is for the MK frame at this time.

http://novationracing.com/

 

[edgo897]

I'm using an 82 YZ490 arm on my project. It lines up perfectly with the shocks. I had to drill out the swingarm bolt holes a little.

 

[pcnsd]

For the first swingarm, I've been told by Aprilia owners , that it was one part of these bikes. See the 2 pics.

Well, I stand corrected. That is clearly the same swingarm. Here is a pic of one from a 79RM400. Similar, but not the same.

Here is one I built for my 82CR430. I bent it slightly landing short on a double, which brings up the relative merits of aluminum as a structural metal in comparison to ChromeMoly steel. The swingarm I built weighed just 8 oz less than stock and failed in use. I believe one could be built on the same pattern, but with 1/4" plate on the main members instead of 3/16", but it's weight would be very close to the stock unit.

Still, aluminum just looks cool...
Regards,
PC

 

[schimmelaw]

PC,
Niiiiiiiiiiiiiiiiiiiiiiiiice. Alot of work right there. Wish I had those fabrication skills. I applaud your efforts regardless of structural integrity, weight issues or any other problems you may have encountered. Looks cool!
Rick

 

[Picklito]

Those aluminum arms do look trick, but I'm wondering about the 'real' functionality of this. I've had pretty darn good luck with the stocker, and they're not too hard to find if you DO need a replacement. But who ever said 'trick' was rational?

 

[pcnsd]

Those aluminum arms do look trick, but I'm wondering about the 'real' functionality of this.

The stock swingarm is made from high quality chromemoly Swedish steel. It is the metric equivalent of our 4120/4130, very unlike the low carbon steel (1006) Japanese frames of the same period. It is lightweight, strong and well designed for it's use. (My opinion here.)


Regards,
PC