Maico swingarm dimensions.

[firko]

Can somebody pass on the following dimensions for the both the '79 Magnum and '81 Maico swingarms please? If someone has a Thor arm to suit the '81 model I wouldn't mind the dimensions for that as well. Thanks in advance

* total length
* pivot to shock mount
* shock mount to axle centre
* inside width at pivot
* inside width at the axle end.

[Husky500evo]

Total overall length of a Magnum swingarm is 572mm (pivot centre to end of arm is 555mm).
Total overall length of an '81 swingarm is 607mm (pivot centre to end of arm is 590mm).
Pivot centre to shock mount centre on the Magnum is 300mm and is the same on the '81.
Shock mount to centre of axle slot on the Magnum is 225mm.
Shock mount to centre of axle slot on the Mega 2 is 260mm.
Width of the Magnum & Mega 2 arm at the pivot is 205mm.
Inside width at the axle end is 175mm on both the Magnum and Mega 2.
The Magnum swingarm has axle adjusters that pull backwards, where the Mega 2 adjusters pull forward (or push backwards depending on which way you look at it) . The Mega 2 swingarm has a slot for the lug on the brake backing plate , where the Magnum uses a mounting hole on the swingarm for a brake stay to bolt to .
My Magnum measurements came from my '78 GS 400 swingarm, which hopefully is the same as the '79 MC.     

[paul]

maico only thor swing arm
* total length                      610 mm
* pivot to shock mount         295 mm
* shock mount to axle centre 260 mm , would vary a bit ,my axel is in the center off slot
* inside width at pivot           205 mm
* inside width at the axle end. ? wheels in the way

[firko]

Thanks for the info fellas. The reason I asked is that I bought an original Thor swingarm supposedly to suit an MX6 Can-Am in the hope I can modify it to suit an '81 Maico. Sounds like a big "maybe" but for $200 it was worth the punt. The swingarm is in perfect, polished condition with very few scratches or blemishes.

I'm really pleased to find that it looks like the arm will fit the '81 Maico with only minor modifications. The Can-Am Thor swingarm dimensions are in italics compared to the Pauls Thor Maico arm and the inside width from Evos stock arm..........

* total length                      610 mm.........610mm
* pivot to shock mount         295 mm.........340mm
* shock mount to axle centre 260 mm ....... 230mm
* inside width at pivot           205 mm........210mm
* inside width at the axle end.205mm.........205mm

What's become apparent is that with a Saturday arvos work the Thor Can-Am swingarm will fit the '81 Maico. The biggest job is to relocate or modify the shock mount forward 45mm. That's a pretty straightforward operation...grind the old mount off and reweld it 45mm forward. Another way is to weld a plate to the mount to enable a new shock mount hole to be drilled. Another alternative is to use a longer set of shocks but I'm not sure of the ramifications that would have on the handling and geometry of the Maico. I'm hesitant to muck around with geometry that obviously works so well as it is.

The other needed modification is to mill 2.5mm from the width at the pivot end. Thankfully there's 3.5mm of 'overhang' on each side so it's an easy operation. The only other mod is to machine up some new bushes and figure out an axle adjuster setup from a later bike. I've never liked the Maico setup, even though it works OK.
Any suggestions on a later adjuster that may work?
Any suggestions of swingarm bush material?

[brent j]

For swingarm bush material I prefer to use Aluminium bronze instead of phosphor bronze or LG (leaded gun-metal) bronze.
The Aluminium bronze is stronger and less likely to deform under load. I’ve found with the Yamaha 500’s, the slow, heavy power pulses tend to deform the softer bush material out the sides. I’d expect similar problems with the power of the Maico

Now watch this open a big can of worms!!!!!!!!!