swingarms.com

I have a JMC swingarm I bought from the swingarms.com website a number of years back. My experience was sort of mixed, but it turned out alright. I specified a Z1 arm 1" over w/o brace to match a donor ZX-11C rear wheel, use dual shock mounts. Took about 10 weeks for the thing to arrive as this utterly fantastic gleaming piece of lightweight aluminum art.

But the details of fitting quickly became a nightmare. In a way, I can understand the problems -- the engineering to deal with the back end geometry is significant. And I was trying to wedge a big-ass rear meat/axle in there - 180 fits. Long story short, I had to slice into my sweet new swingarm and have a welder move the shock mounts. Also had to custom machine the rear hub to avoid shock/sprocket interference and get chain run right. ZX-11C has a very wide rear axle.

I was in contact with Stephen at JMC several times and can tell you the customer service is just excellent. Stephen reimbursed me for the welding work and apologized.

A few lessons I learned:
- Chain/sprockets/shock geometry interactions are tricky for the amateur engineer. Extending the swingarm actually helps to move the shock mounts away from the sprocket and chain, separate those issues. Mine all converge in one spot.
- The Z1 frames seem to vary quite a bit -- my chain JUST slides past the front frame tube with 7/8" offset sprocket, but dragged on several hard pieces requiring further customization. I have heard some only accepting 5/8" offset without flattening/moving the frame. Am using an outboard bearing support for 7/8" offset sprocket from PMFR (also beautiful piece btw) and 530 chain conversion.
- Damn near everything in the rear end drive is custom somehow now, not quite stock for any of the Kawasaki product's involved. The bike works great, but it's a lot of info to keep track of. I limited the changes where possible. E.g. My brakes/chain/wheels/tires are all ZX-11C.

wow!! Thanks for that info. Hopefully I will not have as many issues as you had. It is comforting knowing Stephen stood behind his product. With that said, Nothing worth while is easy. I accept the challange of this project. I will work through it. That arm and wheel looks sick!!!

Anybody have experience with Klasmo arms??

TexasKZ wrote:

Anybody have experience with Klasmo arms??

I've only got about 40 miles on my Klasmo arm but I'm really happy so far. I had to have spacers machined and lining everything up was a real bear, but I'm happy with how it came out. They custom made this arm for me at 6" over, but then they added it to their site.

I think if you went for a stock length it would be a lot less work since it includes mounts for the brake caliper arm and the chainguard. The klasmo arms are also sold www.americanclassix.com

Here is the stock length unit from american classix - it's going for $695 and looks pretty good:

This is a good thread, thanks for the feedback elseed & 79MKII. Those are both beautiful arms, if I do the upgrade I think I'd go with the JMC 2" over with a lower brace with non eccetric adjusters. It seems to me that the eccentric adjusters move the axle position enough to make a noticeable difference in chassis geometry and effect handling response (I could be wrong though). I have a custom made (steel, unbraced) 2" over stock arm (S&W shocks)running a 160 60 18 tire with stock front end and the bike handles unreal. It is Very stable & predictable under hard straight line acceleration and is also really nimble flicking it into corners. Doug

Hi guys.. What's the difference between Eccentric and Slotted adjusters? Are slotted adjusters like the one's on a ZRX1200R?

every time you adjust the chain tension you also change your ride height so you have to take that in to consideration when you go to eccentrics. iknow what is coming next if you use slotted adjusters the same happens it does but not to the same extentent also if you buy the right swing arm you can get it with multiple axle positions so you can adjust your wheelbase lentghs easily. i had a zx-7 swingarm on my little drag bike and it was a pain because every time i adjusted my chain i had to adjust my wheelie bars as well. just was not worth the effort. so i now have a zx-7 swing arm and z1 drum brake rear wheel3.5" rim for sale or to use on some street bike project.

That answers my question.. lol Thanks tb

not a problem ope that explains things in plain engrish

engrish?i tought you was canadish!:laugh: