[pawn]

I'd like to lengthen the rear of my bike a bit. I have a 74 cb450. Are the CB swinngarms interchangeable from say a 750 for a 550? Or are there any longer swingarms that would work with minimal modification?

thanks

 

[66Sprint]

A 360 swingarm is longer and will bolt right on... The disadvantage is you have to run a smaller-diameter axled wheel, or enlarge the adjusting slots....

 

[jayel]

A 360 swingarm is longer and will bolt right on... The disadvantage is you have to run a smaller-diameter axled wheel, or enlarge the adjusting slots....

hmmm I know where there is a old 360 laying in the weeds, so the differece is a 17mm axle instead of the 450's 20mm, will the 360 wheel/brake work? how about the chain guard? how much longer is the 360 swingarm? (already got the bikes out of winter storage and don't have anything to do, project withdrawal syndrome hands shaking, sweating, slightly queasy feeling) still a little to cool for long rides only known treatment other than project fix

 

[tbpmusic]

hmmm I know where there is a old 360 laying in the weeds, so the differece is a 17mm axle instead of the 450's 20mm, will the 360 wheel/brake work? how about the chain guard? how much longer is the 360 swingarm?

The frame end (closed) part of the swingarm is the same - same bolt and everything.
The 360 swingarm is slightly longer, maybe an inch, but a 450 wheel fits in pretty good. You may have to finagle the spacers a bit. The axle holes in the 360 swingarm will have to be ground larger to allow the larger 450 axle.

I've heard (from Steve, maybe) that the chain guard might be a problem.

A 360 wheel/brake would bolt up to the 360 swingarm, and would probably work fine if you can get the sprockets to line up (but there's no reason to expect they wouldn't).
I can't say that for sure, since I never actually did one that far - don't have a 360 wheel......
The brake is the easy part, you can make that work.

However, I successfully grafted a CB400T wheel and brake to a 450, works fine.
Sort of a description in here - http://home.comcast.net/~tbpmusic/id54.htm

My problem was the opposite - I used the smaller diameter 400T axle in a 450 swingarm - so I had to make a couple of collars to put around the axle at the points it went through the swingarm holes.

 

[66Sprint]

Memory says it's more like an inch and a half to an inch and three quarters longer.... This is enough to lower the ass-end a couple inches as well (custom or sprung chopper)....unless you run longer shocks.....
Wheel/fender interface changes as well.......
I tried it on a cafe' that I was racing on a course that had LOOOONG straits.....Great for that but turn radius and "nimbleness" suffered... My 450 had 360 suspension on both ends for that race, plus, the 360 wheels were laced to alloy rims;

 

[jayel]

360 shocks any longer or the same? will they bolt up? don't plan on roadracing so could use a little more wheelbase for on the road, how about 360 front forks what involved there? my 450 is a CL K4 with CB pipes

 

[tbpmusic]

360 shocks any longer or the same? will they bolt up? don't plan on roadracing so could use a little more wheelbase for on the road, how about 360 front forks what involved there? my 450 is a CL K4 with CB pipes

360 shocks will bolt up, they're approximately the same length.
360 front end needs to go in a 360 stem and triple clamp.
The 360 forks are smaller diameter than 450 forks, and the stem/clamp has different offset and fork spacing than a 450.

To make things easier, get 360 stem/fender/brake/wheel, then the whole thing bolts up to a 450.

Exhaust pipes don't matter.

 

[jayel]

thanks bill

 

[66Sprint]

The ultimate is to do what Bill did..... 360 or 400T trees, with 400T forks (CB, CM, whatever) ... The 360 rear wheel/sprocket lines up fine, a 360 front wheel will fit in the 400 forks (spacing/size might have to be adjusted on rotor, but the drum goes right on...)
I'd recommend 550 or 750 (size, not factory) shocks to slightly raise and stiffen the back end.... Steve

 

[MNellis]

[Threadjack:]

Dang Steve, that's an old picture but a nice looking 450 racer, no knee puck or anything. It looks like it might be Sebring or maybe Jennings in FL.

[/Threadjack]

 

[Bird76Mojo]

That picture is just farkin cool!

GB :mrgreen:

 

[66Sprint]

Mike.... St. Pete, late 1970's......My first WERA race (You'll notice the "dirt" racing pants used as protective wear...LMAO!) I didn't lose a place...started last, finished last... But I finished...... I beat several DNF's....LOL...

 

[MNellis]

Mike.... St. Pete, late 1970's......My first WERA race (You'll notice the "dirt" racing pants used as protective wear...LMAO!) I didn't lose a place...started last, finished last... But I finished...... I beat several DNF's....LOL...

Cool, that bike would be right at home at any AHRMA event nowadays. Noticed the leather pants and road going jacket. It kind of reminds me of wearing a long sleeve t-shirt, Levis, Torsten Hallman gloves and a 3/4 helmet with Jota mouth protector during my first MX race. Oh, and I think I wore tennis shoes too.

 

[pawn]

So all in all, I could get along with the 360 swingarm and a smaller diameter axle. Is that last part something I can achieve easily while retaining my 450 wheel? Shim, or collars as one person put it, sounds plausible but how safe?

 

[66Sprint]

If you're using the 450 wheel, widen the slots..... I have some 500/4 "blocks" that will fill the "back-end" (once narrowed) or you can weld a bar of keystock across (my preferred method)...... The 350/360 wheel is easiest to use, and the only major difference is swept braking area (~25% less) but it works fine... Better in my opinion, as there is less likelyhood of lock-up.....

 

[pawn]

By "widen the slots" are you talking about the droputs? So just get in them with a drill or grinder and make them able to accept the larger axle...correct? Is the 360 wheel narrower, or is it just a matter of axle size and a smaller drum? (sorry for all the q?'s I'm totally new to this.)

 

[66Sprint]

Widen the adjustment slots to fit the larger diameter axle... A good mill file will do it, but you want to go slow so as not to get it too "loose".....

 

[pawn]

Ok that's what I thought. Thanks for all the info. Soon enough it will be time for me to begin my search for a 360 swingarm.

 

[66Sprint]

Yes, the 360 drum is a bit smaller, and it's a 36 spoke wheel (the 450 is 40 spoke), but other than that (and the smaller diameter axle) the rim is an 18" like the 450..... I have run them without any "strength" problems, and the sprockets are available and take the same size (530 H) chain... (same as the 350 sprockets).... Steve

 

[pawn]

So either can work? The 450 wheel as long as the slots are made wider to accept the axle, or the 360 wheel as is, but on the 450 bike...