CB350 bracing

Sweet Mike.....will work for beer:up: I'll know tonite if I'm in.....thanx.....I'll pm yall.

Hey CP.....I thought the same thing....its like front half SL350....back half CB360....cool.:up:

 

that frame was built for george decamp by frank camilliere. its now ownded by scott "evil one" vile i think. all you old schoolers should know frank. he was a designer and builder for yetman. read kevin camerons book. i wish i could afford that kind of work to be done. too cool.

the red bike is chris'. yeah one side had bolted up lugs. think srx. the other side was welded. the gas tank had to be cut in half and rewelded too. i rode that bike for a season, thanks to chris. you can see more of franks stuff on his website.

camilliere.com

jc

 

Thanks for the input/ wintertime entertainment If the inner rear fender was not permanently mounted then a triangular bar from the lower left beam the the upper right shock mount and another from the shock towers would be good. He also mentioned a huge help would be to solid mount the upper bush in the valve cover. I wonder why it is rubber mounted/ why it is there at all?
CharlieY did mention that just a braced swingarm made his CB feel like it flexed more. Most modern sportbikes and performance cars are designed with a certain amount of flex in the chassis and too stiff can be a problem. I myself have never felt any kind of handling issue with the CB, even with the cheap progressive rear shocks I run. I guess peer pressure/ possible frame or engine case failure is getting the better of me.
BTW JoeC, thanks for the nice piccies.

 

Charly, the cases cracked at the rear motor mount. Too much frame flex. Brace 'em up the best ya can.

 

So was that in a SL350K1 or later frame (dual downtubes)? Those rear engine plates are half as thick as the CB/CL/SL350K0

 

you all are crazy. Keep adding the weight and filling your heads with ideas. All this has been done before and not by the seat of the pants. Why not make a jig and load the frame to see where the flex is? A stiff frame is not necessarily a good handling frame. IT's the SL mounts that will break- never seen a CB CL rear motor mount break. I will show you some pics of my frame- mostly the places where I heated it up with a torch and beat it silly with a 20 pound sledge to get my special manifolds and carbs to fit.... now quit messing around with melting metal and take some track days if you want to beat the competition.

 

Dean, the frame was a CL not a SL. Hey Buff if it can be broke, I'll figure out how to do it.

 

Spoil Sport!!! :down:

 

Buff, 6 oz of steel tubing to make the bike feel better to Steve ain't nothing...especially considering Steve's size (and mine, hell I'm bigger than he is). Just gotta run a few more miles and skip a couple of six packs....

And the cases on his bike broke, right at the motor mount. Had to come from flex somewhere. Considering the fracture, we braced it to eliminate the flex in that axis. I could have put it on my frame jig with a measured load and indicators to measure the amount of flex before and after, but since he had races to run so we reinforced it in situ.

And Steve was out doing a trackday this weekend, so he's working on that angle too.

 

"quit messing around with melting metal and stuff and just order a drixton from me"

haha





chris' bike does feel like it weighs a ton. but it goes around corners great. no chatter at all, and nice an linear. it probably felt perfect with 48hp! mine by comparison feels like a scalpel. like i can flick it from one side to the other. i can change line mid corner with no thought at all. it literally goes where i look so well, i have to be careful. for a while i was running off the insides of corners form going in too early. compared to my old bike it feels twitchy.

and just to make more of a mess of this thing, tim tilghman ran 138's and i think a 37, same as toe cutter at summit last time he was there. stock motor, no dyno time, with a cb450 front brake. his frame is totally stock i think, and he has shit for shocks.

there are enough pics of my frame out there.
anymore will cost you.

 

see what happens when i cant race!

 

"Why not make a jig and load the frame to see where the flex is? A stiff frame is not necessarily a good handling frame."

but the jig has already been built and this research was done to the CB, CL, and SL frames........some one very prominent among CB tuning once told me the secrets of which was best and why, but unfortunately i was sworn to secrecy.

i will give you a hint......toecutter is too cold!

texy

 

buff, you built one too?

didn't ya get the memo?

guess not!

tex

 

tex- and i thought you were a smart boy. I think we are in the same camp on this one commrade...

 

Buff-we need to see Todd's racing notes on testing results he did and are willing to pay...tell Ari will ya?

 

Hey Joe,
That link is
http://www.camillieri.com/

Great stuff. Y'all should check it out.

 

im a retard....yes, youre right.

http://www.camillieri.com/

 

Here's what Tex has been hinting at...
After watching the talk for years on CB350 frame bracing I had decided to finally let others know about my development over the last 15 years of racing the Honda twin.
In the mid 80's, a vintage racer, John McCormack, asked me to do some work on his fleet of vintage race bikes. One of his bikes was a Pops Yoshimura built CB350, and my job was to refurbish it and get it race worthy. That bike was a beauty. RSC-kitted, light crank, ports polished to a mirror, fiberglass tank, seat and fairing. The frame was braced with tubes connecting the center spine above the rear engine mount, to the frame tubes running up to the shock mounts.
Frank Smith asked me to build him his first CB350 a couple of years later, and we had replicated these braces, plus seam welding the spine, as had been recommended by some of the Brits for IOM durability. On Franks bike, the braces putting a load into the middle of the frame tubes caused the frame to crack on the rear side tubes. We had added gussets to repair, and I recall that they cracked again. When I had started to race myself in 1993, my own bike had the same braces and seam welding. Over the years, I had seen all kinds of bracings on CB350s by different people, there has been a lot of experimentation going on.
For the 1999 racing season, I had joined the Giannini race team with Chris Marshall and Chris Kellerher. That year was an epic battle between Chris M. and myself on our CB350s, trying to beat each other in V1 and V2. I had decided to switch to the late SL frame with the dual front downtubes, it looked more to my eyes like a real race frame compared to the pressed steel CB frame. At the first Summit race, the chatter on both wheels was enormous! Billy Hauser was watching at turn three and talked to me later. He held up his palms about three inches apart and said he saw this much light under both of my wheels going through the turn! I wanted that frame to work, so I braced the hell out of in in June of that year. I had added two more backbone tubes from the steering tube back, tubes from the swingam pivot up to the backbone, a swingarm brace, and more. Around the same time, I had revalved and resprung the forks. The results were fantastic! The bike had virtually no chatter, even with a heavy front Buffalo brake. It steered beautifully on its side in turns.
In 2001 I had retired from racing for championships, my priorities are now my wife and daughter. I got a lot of flack over the years, from some of the racers,(Chris Bernstein) for having not the prettiest bike, so I built a replica of that Yosh bike for myself, going back to the CB frame. I wanted to know exactly what frame bracings worked, or didn't. I had set up a test jig, by bolting up the axle into a large hydraulic press frame, and twisting the head tube with a long pipe. Dial indicators were placed on each part of the frame to measure how much each tube bent. I had tested my superbraced SL frame, a stock SL frame , and a stock CB frame. The SL frame flexed a huge ammount. Surprisingly, the stock CB frame was only slightly more fexible than the superbraced frame. Dramatically, the stock swingarms flexed like mad. The stock swingarm accounted for over 90% of the total deflection between the rear axle and the headstock, and my braced swingarm reduced that flex by 60%. So, my current chassis has my braced swingarm, and a completely stock frame, with only the centerstand mounts removed. To prove a point, it even has all of the original tabs.
My current bike handles like a dream, every bit as good as my old superbraced chassis did.
In order of priorities, get a good spring and valving setup for the forks, with decent shocks. To stiffen up the chassis, add a properly designed swingarm brace. Alter the geometry to change stability and turn-in. A fork brace can reduce the head wagging under maximum braking.
I would seriously doubt anyone feeling a difference with frame bracing if the bike still has a stock swingarm.

Stan

 

Thanks for this feedback Stan:up: