Saw this online recently
Designed by Denis Curtis of CMR Racing, the guy that designed the frames for the last Team America that went to Philip Island
https://mojoyamaha.com/
Sadly Denis passed a couple of years ago and Byron Cox (his longtime welder) is carrying on as Cox Customs. Byron has all of Denis's designs and access to all his stress analysis data. He has frames for RDs, TZ750 and 250/350s, XS650s, FJs, CB350s (twins and 4s), GS/GSx or TR Suzuki's ... and more....
It is over designed with tapered roller bearings, massive stiffness without a lot of weight (less than a DG swinger) and improved adjusters... basically it's the TZ 250/350 swingarm CMR Racing has been building for years for their "kit" lowboys, with dual shock mounts.
Constructed of 4130 (the welds are PERFECT. Byron is an artist with a TIG torch)... because all swingarms flex, BUT a steel one will return to it's original shape faster than aluminum
I was a long time friend of Denis and can't recommend his work enough... I have a CMR TZ250/350 lowboy, a custom TZ (G) swingarm (that uses a longer than OEM shock and a TR750 framed GSx750
Byron also makes fuel tanks, he made me a TA125 tank, a Norton Commando tank and a TZ/TD tank
https://www.facebook.com/people/Cox-Custom-Fabrication/100069897804194/
Looks nice!
Hi,
I was in contact with Byron Cox a few days ago. Weight of the swingarm with all the parts included seen in the above picture is around 9 lbs(around 4kg). I will order one as I have seen a TZ frame in flesh Byron made. Superb quality.
Regards Uwe
:swoon: dammit.
youre going to make me put a ridiculous swingarm on a bike that doesnt need it. :homer:
Nice, what is he selling them for?
I got quoted 1200 Canadian Dollar + shipping. When ordering you have to pay a 50% deposit and the final bill have to be paid before shipping out the finished product. Not cheap but in my opinion worth the part
Regards Uwe
$880 USD...It's a very nice piece, and I understand structurally superior to the aluminum Motolana 'arm I bought. But I could have almost gotten two Motolanas for that price.
Quote from: 85RZwade on December 09, 2022, 09:47:05 AM
$880 USD...It's a very nice piece, and I understand structurally superior to the aluminum Motolana 'arm I bought. But I could have almost gotten two Motolanas for that price.
Except the Motolana has been out of stock for months and this is made in the US!
Quote from: rlloydm on December 12, 2022, 12:13:43 PM
and this is made in the US!
Actually Canadian made. Supporting a Socialist economy! I LOVE it.
Quote from: DesmoDrew on December 12, 2022, 12:20:51 PM
Quote from: rlloydm on December 12, 2022, 12:13:43 PM
and this is made in the US!
Actually Canadian made. Supporting a Socialist economy! I LOVE it.
Well, I appreciate the Canadian way of running a country far more than the Thai or Chinese way. Or Russian or Vietnamese for that matter. MotoLanna has some nice parts at a very good price, and I believe they are all made in Thailand. And as a footnote to that, did you known that just criticising the king of Thailand is a serious crime, that can result in several years of prison. And there is a lot to criticise about him and his ways......
cool guys. let's keep it on the swingarms themselves here. :thumbs:
It's a great looking swingarm and the large OD tapered rollers are one of the few non-plain bearing swingarms I have seen that actually make sense. One of these days I am going to build one for my RD, but with aluminum tube, and round tube for the arm section. I have never cared for the mono-shock look arm on a twin shock bike, but that's just my taste. It would be cool to machine some mandrels and create an oval section tube in house, but that's probably more expense and work than I am up for.
Quote from: sav0r on December 13, 2022, 02:56:25 PM
It's a great looking swingarm and the large OD tapered rollers are one of the few non-plain bearing swingarms I have seen that actually make sense. One of these days I am going to build one for my RD, but with aluminum tube, and round tube for the arm section. I have never cared for the mono-shock look arm on a twin shock bike, but that's just my taste. It would be cool to machine some mandrels and create an oval section tube in house, but that's probably more expense and work than I am up for.
With those tapered roller bearings is the pivot bolt just tightened up till the bearings start to bind, and then slacked off slightly with no crush tube between the bearings?
Yes. Like any tapered bearing it runs with "some" preload. The same as on your car wheels
... and you'll never convince me that a tapered bearing swingarm pivot is anymore than bling, with a side of overkill.
A little bit of "bind" in the swingarm pivot isn't a bad thing. That "bind" works as a damper on the spring, like the shock. Up to a point that "bind" is a GOOD thing
The TRICK is that "bind" has to constant.
There is nothing wrong with the stock setup, with a bronze bush. If you're putting enough force into your swingarm that you're mooshing a proper fitting bronze bush, you've got other problems
Just FYI Motolanna swingarms are back in stock - just ordered one for my race bike: https://www.motolanna.com/ourshop/prod_448876-Swingarm-Aluminum-Alloy-SuperTuff.html
It looks like a Radian swingarm, which I like to run on RD and XS.
(https://www.dotheton.com/index.php?attachments/a49cade5-67c3-43bd-b7f3-5fcada2aaf5c-jpeg.220765/)