1979 CBX Restomod

[steve murdoch icoa #5322]

Not sure that i need any of the "engaging" aspects of the CBX flex. haha.
How long are the ZRX shocks?

[Z3n]

Not sure that i need any of the "engaging" aspects of the CBX flex. haha.
How long are the ZRX shocks?

They're about 13.75 inches long, iirc. Amount of ride height will depend on where I get the shock mounts welded in.

[Jeff Bennetts]

From what I've heard, a large part of the problem with frame stiffness was down to the plastic swingarm bushings allowing massive flex between the swingarm and the frame - I'm not ready to send the frame off to powder coat yet, so I'm gonna get it together and see if the stiffer forks, swingarm, and solid swingarm pivot design brace the frame enough. If they don't, then I'll brace it before it gets powdercoated. :)

This bike will never be as fast / performance focused as a more modern bike, so having some flex in the chassis can make it more engaging to ride at street speeds which isn't a bad thing.

All those stiffer components and stronger front brakes will actually emphasized the weak areas of the frame, the bracing below the battery box can be added, similar to what Honda did with the 81/82 CBX, it's a simple,effective and clean modification.

Do a search on early model frame bracing here and a few self explanatory pictures should pop up.

[jt]

Not sure that i need any of the "engaging" aspects of the CBX flex. haha.
How long are the ZRX shocks?

They're about 13.75 inches long, iirc. Amount of ride height will depend on where I get the shock mounts welded in.

You might want to measure again, mine are 14-1/4" center to center.

[jt]

Have two things to address - the first is the shock bushings (I think i can get away with removing the old metal spacer bound to the bushing), the second is getting the swingarm shock mounts welded on, which requires making sure my test fit and such is in place.

Z3n
I'm in the same boat on my swing arm swap using the ZRX shock. I'm probably going to go with this so might be of use to you and others. I removed the stock bushing and got this Honda bushing and installed. See pics pretty self explanatory. You will see I've backup the bushing with two thick washers to try and move the shock out some to offset the slight lean of my shocks. There is a gap as you see in the first pic, but gets better at the end once it is tight there is no movement. This is just using bits and pieces from the shop will tidy things up with better looking washers on final assembly. Be interested in you come up with something else.

[img][/img]

[img][/img]

[img][/img]

[img][/img]

[Z3n]

Z3n
I'm in the same boat on my swing arm swap using the ZRX shock. I'm probably going to go with this so might be of use to you and others. I removed the stock bushing and got this Honda bushing and installed. See pics pretty self explanatory. You will see I've backup the bushing with two thick washers to try and move the shock out some to offset the slight lean of my shocks. There is a gap as you see in the first pic, but gets better at the end once it is tight there is no movement. This is just using bits and pieces from the shop will tidy things up with better looking washers on final assembly. Be interested in you come up with something else.

Oh, this is super useful, thank you! I'll do exactly this as well.

And yes, I didn't measure the shocks, just tried to remember the length off the top of my head.

All those stiffer components and stronger front brakes will actually emphasized the weak areas of the frame, the bracing below the battery box can be added, similar to what Honda did with the 81/82 CBX, it's a simple,effective and clean modification.

Do a search on early model frame bracing here and a few self explanatory pictures should pop up.

Yeah, I'll ride it and see - if that ends up being the case (it probably will), I'll clean it up and weld it up. Thanks for the advice, as always!

[Jeff Bennetts]

Just don't kill yourself in the interim, Z3 I'm not sure how much aggressive riding you have done on a stock CBX but I'm sure you're familiar with the term "hinged in the middle" the CBX suffers from this malady, like most Jap bikes from that era but with 600 lbs of mass driving the forces.

You don't have to be riding fast to encounter the hinge that turns into a wobble, that turns into a tankslapper. All you need to do is compress the suspension and hit a bump or ripple while in a hard turn. The bike will want to stand up out of your lean while you're still in the turn, if you hit the brakes you're cooked, you have to ride it out hopping there is enough road or run off on the high side of the turn.

Although your new setup will help the compression of the suspension it won't help the frame flex.

[wyly]

You don't have to be riding fast to encounter the hinge that turns into a wobble, that turns into a tankslapper. All you need to do is compress the suspension and hit a bump or ripple while in a hard turn. The bike will want to stand up out of your lean while you're still in the turn, if you hit the brakes you're cooked, you have to ride it out hopping there is enough road or run off on the high side of the turn.

yup, compression after hitting a big dip in the middle of a high speed sweeper ...scared the crap outta me ...

[Syscrush]

I don't ride hard on the street, but I do definitely encounter serious frostbelt bumps mid-turn - even when trail braking (e.g. on a highway offramp).

I had the symptoms attributed here to a flexy frame back when I had garbage suspension - I don't have those symptoms since going to high quality gas-charged shocks and braced 39mm forks with full cartridge internals.

Best bet is to get it together, ride it, and see how it feels to you.

[Z3n]

And it is together!


What got it here - had the swingarm welded up, replaced the oil sensor, removed the R/R, installed a modern main fuse, pulled the carbs to clear some grit from the #4 float bowl, reinstalled the motor mounts, hooked up all the cables, addressed the wiring, installed the air filters, checked the chain fit.

Needs some new swingarm spacers installed (they're on the way), and a bunch of random things, shock spacers, tires, centerstand stop, steering stop, chain guide, install the Dyna ignition, fuel lines, crankcase breather lines, clean out / de-rust the tank, slide the fender back a bit, and then it will be on the road! If all the parts show up, I'll have it done this weekend - had to order a 98 ZX6R swingarm slider from England of all places. Also needs mirrors, rear brake, and a couple of other minor odds and ends.

Then it's getting it re-registered in CA, paint it in the official color of lazy masculinity, figure out the ducati headlight, RFID ignition, steering damper mount, and maybe replacement gauges if needed.

[steve murdoch icoa #5322]

A couple questions on this latest step on your build.
What jetting did you settle on for the pods?
If the swingarm spacers were for proper frame clearance , can you provide some dimensions?
And wtf is the "official colour of lazy masculinity"? haha.

[daves79x]

Yes, also interested in the carb jetting?

Dave

[wyly]

wow impressive amount of work accomplished in only 6 months ...

the guy who re-built my engine needed 11months...

[Syscrush]

Keep up the good work!

[Jeff Bennetts]

Looks great so far Z, what are you doing for shock spacers and do you mean something to get the top shock mounts outboard more to be parallel with the swingarm shock mounts?