Topic: Alloy fork brace from Carpy for cb750. Anyone used one?

[scottly]

I believe the longer fork lowers were first used on the K7s.

[Retro Rocket]

Never had a tweak bar but have used fork braces , both GSXR front ends i have have factory fork braces {a lot stronger than the Honda guard bracket} . Twist is totally different to flex, all front ends flex to some degree, its the twist, especially under brakes  and at speed that needs help, remember, the front and rear wheels have huge gyroscopic effect, trying to twist everything as soon as the wheel starts rotating, the more speed, the more this effect tries to take over {hold a bicycle wheel buy the axle and rotate it, it tries to rip itself from your hands}.  The lower down the forks can be braced the better, the twisting starts at the axle.... 

[scottly]

This is a generic fork brace that I fitted to my K7 forks. It was originally mounted on a Kawasaki. I had to slot the holes in the top plate to fit the narrower K front end. As Tkat mentioned, the shorter lowers, plus the retention of the dust boots, would make this a much more difficult machining project than the simple brace I'm using. I think his price is quite good for the work involved.

[MCRider]

Never had a tweak bar but have used fork braces , both GSXR front ends i have have factory fork braces {a lot stronger than the Honda guard bracket} . Twist is totally different to flex, all front ends flex to some degree, its the twist, especially under brakes  and at speed that needs help, remember, the front and rear wheels have huge gyroscopic effect, trying to twist everything as soon as the wheel starts rotating, the more speed, the more this effect tries to take over {hold a bicycle wheel buy the axle and rotate it, it tries to rip itself from your hands}.  The lower down the forks can be braced the better, the twisting starts at the axle.... 

You're not telling me anything I don't know.

All I'm saying is the tweak bar will stiffen up the front end v not having one. I know this.

[Dream750]

Anyone know what ever happened to the CB750 fork brace that 754 was working on?

It sure did look promising in this thread:

http://forums.sohc4.net/index.php?topic=31564.0;nowap

[seanbarney41]

wow...that's cool.  I can make that myself!  Thanks for posting Dream750, and thanks to 754 for the idea.

[scottly]

Anyone know what ever happened to the CB750 fork brace that 754 was working on?

It sure did look promising in this thread:

http://forums.sohc4.net/index.php?topic=31564.0;nowap

Thanks for posting the pic; I could never visualize what Frank was describing. 

[Shanedalion]

No response from tkat yet...

[Retro Rocket]

Never had a tweak bar but have used fork braces , both GSXR front ends i have have factory fork braces {a lot stronger than the Honda guard bracket} . Twist is totally different to flex, all front ends flex to some degree, its the twist, especially under brakes  and at speed that needs help, remember, the front and rear wheels have huge gyroscopic effect, trying to twist everything as soon as the wheel starts rotating, the more speed, the more this effect tries to take over {hold a bicycle wheel buy the axle and rotate it, it tries to rip itself from your hands}.  The lower down the forks can be braced the better, the twisting starts at the axle.... 

You're not telling me anything I don't know.

All I'm saying is the tweak bar will stiffen up the front end v not having one. I know this.

Good, someone else may benefit from it....   While the tweak bar may add some stiffness where you had it,  its in the wrong place to work effectively, that was my point. The best place for a brace is in the middle between the axle and bottom clamp, because the tire is in the way it usually gets mounted at the top of the fork lowers ...... Your new brace is far superior...

[crazypj]

Hi Retro,
You know the 'tweak bar' was designed for chopper forks 6"~12" longer than stock a flexys as F@#$%
Stop encouraging people to waste money on the crap 
For anyone who doesn't know, usually, the only thing stopping lowers twisting is the axle, if you prevent twist you'll get instant handling improvement. (which is why running without fender  is A BAD THING  )
 The brace was never designed to 'force' both sliders to move together, just prevent twist
Suzuki used 1.0mm steel on early ones and 2mm alloy cross piece on the last ones, but, it's 76mm wide.Bends pretty easy up and down but impossible to twist lowers when assembled

[Toxic]

My tweak bar is snugged up right under the lower triple tree, i'm going to mill out the center to instal some ultra bright LED's.  That's all it is good for, A light bar.

Carp's location is absolutely wrong and dangerous

[Retro Rocket]

Hi Retro,
You know the 'tweak bar' was designed for chopper forks 6"~12" longer than stock a flexys as F@#$%
Stop encouraging people to waste money on the crap 
For anyone who doesn't know, usually, the only thing stopping lowers twisting is the axle, if you prevent twist you'll get instant handling improvement. (which is why running without fender  is A BAD THING  )
 The brace was never designed to 'force' both sliders to move together, just prevent twist
Suzuki used 1.0mm steel on early ones and 2mm alloy cross piece on the last ones, but, it's 76mm wide.Bends pretty easy up and down but impossible to twist lowers when assembled

Hi PJ, Was  the first part of the post above a joke.? Because thats what i am saying, i would never use a tweak bar as a brace...   I agree 100% with the rest of your post....

[crazypj]

Yep, didn't come across quite as planned but I thought you'd understand

[Retro Rocket]

Yep, didn't come across quite as planned but I thought you'd understand

Thought so....

[chris mcshifty]

Anyone know what ever happened to the CB750 fork brace that 754 was working on?

It sure did look promising in this thread:

http://forums.sohc4.net/index.php?topic=31564.0;nowap

I want one from him on my bike

[754]

I could probably make it as a kit form, meaning you finish the outside as you see fit, but the bars are drilled and tapped  andld thinned, and holes are in the 2 side plates..

1080 built the one in the pic, think I helped a bit on it. I originally offered it up as a project i would help folks thru that could be done on a drill press and bandsaw and sander, but everyone got carried away discussing if that was actually true , and how it would not fit with stock fender, etc.  It probably can be made to work with a stock fender with slight tweaking, but is quite easy with a custom fender.

[chris mcshifty]

I would want jus like yours it perfect to me and I don't have access to a band saw . How much would it be ?

[crazypj]

It can be done with a hacksaw and power drill, flap wheels, etc. Just a lot longer to get finished (chain drilling and sawing alloy isn't fun)
It can be done though as long as you don't mind working at it  (and you do get more satisfaction from doing it 'old skool')
You would end up with around $5~600.00 brace though (labor time)

[754]

You dont need to chain drill, hacksaw will get it real close.. Will work out a price.. The only part that is hard by hand is the two crosspieces, hard to centre drill and face accurately, hence the kit suggestion. Plus I can carve a lot of weight off the middle of bars, and they will look better.

 Btw the long forklegs were out in 75, on the Automatic.. And not sure what the first 750 F used..

[1080]

My tweak bar is there only to hold up my round aluminum spacer's.
They do little, hence the home built fork brace.
They work beautifully.
First photo is taken this summer, and second photo is 754's original version.

[754]

I think i built the one on my bike with a. Hacksaw, sander, and small lathe.. Way before I got a mill and bandsaw, and rotary table..

[chris mcshifty]

Still want one from you 754 . I was thinking of a dual disc set up on my 500 would still work if I switch to that later on

[754]

Keep in mind that you may have to mod the fender a bit, or are you running a different fender?

[chris mcshifty]

Going to go fenderless  with some fat firestones

[Retro Rocket]

Going to go fenderless  with some fat firestones

Sorry to say but you won't ride that bike round corners fast enough to need a brace with those crappy Firestones mate, the tires and the brace kind of contradict each other, one is a performance mod and the other is a performance killer....