1979 CBX Restomod

[NobleHops]

You both are a total pleasure to work with, thank you guys for the good words.

Best,

Nils

[Z3n]

You're welcome!

Well, as usual I'm terrible at taking pictures while I work, but I did get the ultrasonic cleaner setup. Very handy, even if it doesn't make things as clean as Nils gets them, haha.

Threw the head studs in to see if they could be saved:

The water was clean but the ultrasonic cleaner immediately makes any surface grit cloud off the parts:

And a few minutes later:

The final product isn't quite good as new, but will work well enough for this bike:


After that, spent some time cleaning any residual WPC material off the cams, reinstalled some of the head dowels, and got the cams in for tension testing on the new and old chain. That gave me some baseline values to shoot for with the new cam chain tensioner. From there, some measurements, some screwing about, and that led me back to the comfort of CAD, as it always seems to do:


I'm still waiting on cam chain guides to show up for final fitting, but once those do, it should just be drilling some holes and making sure everything lines up, the chain is tensioned appropriately, and then doing the vertical tensioner.

Also, look at this exhaust! It's full of stars:
http://www.samurider.com/?p=10412

[Z3n]

Ok, so I've finally had the time to get the engine mostly back together, and now I'm struggling with torque specs - the cap nuts for the head studs are listed as:
10mm cap nut - 23-25 ft-lb
8mm cap nut - 14-15 ft-lb
8mm both - 13-16 ft-lb
But there's no listed spec for the head studs themselves - in the crankcase portion of the shop manual, and in the generic areas, the specs are lower than that. What is the appropriate torque for spiral bore head studs?

[daves79x]

Sent you an email with the reply.

Dave

[Z3n]

Sent you an email with the reply.

Dave

Thanks Dave! I'm reproducing that advice here for the sake of future searchers, such as myself!

There is no torque value for screwing the studs into the cases. Just firmly bottom them as far as they'll thread and you're good. Thread tape the studs with open holes into the crankcase (some center ones). Be a bit careful, these castings are somewhat porous and I've had to Heli-coil a few that pulled the threads out because there was not much solid metal in the hole.

I'm planning on using Permatex Locktite Green on them as well.

[Syscrush]

BUMP!

I just found this thread today - by my tally, we have a bunch of stuff in here that I really dig:

1. Upgraded suspension!
2. Fabbed parts.
3. Engine coatings for longevity (I've done thermal barrier coating on my piston crowns and combustion chambers, and dry film lubication coating on piston skirts).
4. Plans for ABS - would that make it the first CBX with ABS???
5. Plans for RFID ignition (I have this on my bike and love it).
6. KTM awesomeness. I had a Duke 690 before the 'X and it was a miracle machine.
7. Dude married to a riding partner (my wife rocks a Ducati Monster).
8. Restocycle vapor blasting porn. My god, I could look at those pics all day (and some days stalking Nils on FB that's exactly what I do ).
9. Not just a link to one of my favorite exhausts, but also a 2010 reference to go with it.

Lots for me to love, here - I'll be watching with interest.

I do have to say, though, that I think if you were to do some custom triples to gain back the ground clearance and to get back to stock (or better) trail, you'll be glad that you did. Keep in mind that you're going to lose further clearance with the (presumed) change to 17" wheels, and that the modern triples with their low offset will add a bunch of trail.

My bike is set up with about 1 degree of rake and 8mm of trail taken out (via custom triples), with a relatively wide Superbike bend LSL Fatbar, and it is shocking how well it turns in and transitions. You're putting so much care and effort into this build, that little bit of extra machining would seem well worth it - especially since it also adds such a nice bit of bling.

Of course, if you stick with the OEM Kawi setup, my bike stays a bit more special, so follow your heart.

[Z3n]

Okay, so it's been quite a while, work got very busy and life got in the way for a bit, but the engine is back together, I'm still working on machining a new tensioner, but my current struggle is with this:





The front cam chain guide has some cracking and has some damage on one of the side rails. Replacements are hard to come by, and so expensive it borderline makes sense to just buy an engine or another bike instead.

So what say you, CBX gurus, would you run it?

On the bright side, the rest of the engine is coming together nicely:


Edit: Whelp, found a primary tensioner and guide for $150 on ebay in good condition, so that solves that problem for now.
Syscrush, I'll definitely consider a set of triples - geometry tuning will be a thing that takes place once the bike is rideable. Getting in the ballpark numbers wise is always good, but I'll see how close it feels before I start mucking around.

Also decided to try to test fit a ZX6 swingarm instead of the ZRX one, as I decided I both would like to avoid losing the centerstand and that I would like to not have to cut/grind on the frame if at all possible. With some parts mix and match, it should mostly bolt on.

[steve murdoch icoa #5322]

Anything to with cam chains and guides i would be contacting 605Brent.
His info is in this thread. viewtopic.php?f=6&t=10351&p=82804&hilit=captain#p82804

[Z3n]

Anything to with cam chains and guides i would be contacting 605Brent.
His info is in this thread. viewtopic.php?f=6&t=10351&p=82804&hilit=captain#p82804

Reached out, CBX tensioners are still in development, unfortunately. I've got one that I can make work, but I'm unable to find similar 6 and 8mm rivets I'd need to replace the OEM ones, or I'd have to grind down some bolts or something to get them to fit - there's not a lot of space in the CBX head for fitting things in :)

[Z3n]

Well, have some time off, so hopefully will be able to make some additional progress over the long weekend!

But the success of today is - with the spacer I had knocked up, a ZX6 swingarm bolts straight in, minus the shock mounts, which are available from Stites on the ZRXOA. This means a couple of great things - no shock spacers needed, no cutting, I can probably retain the centerstand and it clears the sidestand, and will likely clear the 6 into 1 exhaust as well. I think if I strip the polish off the exhaust, it'll also match the engine nicely, which should create a pretty nice, consistent visual effect from engine to swingarm.



This weekend is machining up some parts, and then running the stuff by my welder who does all the parts that are structural (I don't trust my limited skills to TIG in the shock mounts).

A good evening of throwing parts around in the garage!

[NobleHops]

NICE Conan! That is a nice boost and momentum builder.

[Syscrush]

Syscrush, I'll definitely consider a set of triples - geometry tuning will be a thing that takes place once the bike is rideable. Getting in the ballpark numbers wise is always good, but I'll see how close it feels before I start mucking around.

Makes sense - have fun!

[wyly]

But the success of today is - with the spacer I had knocked up, a ZX6 swingarm bolts straight in, minus the shock mounts, which are available from Stites on the ZRXOA. This means a couple of great things - no shock spacers needed, no cutting, I can probably retain the centerstand and it clears the sidestand, and will likely clear the 6 into 1 exhaust as well. I think if I strip the polish off the exhaust, it'll also match the engine nicely, which should create a pretty nice, consistent visual effect from engine to swingarm.

interesting...what year/s of ZX6 swingarm? and what spacer? seems like a very inexpensive and relatively simple conversion

[Z3n]

98-02 swingarm fits the zrx frame without mods so it fits the CBX with the spacer I had made.

Still have to have shock mounts welded on though.

Step by step.



Tomorrow, we see if I actually rebuilt a functional engine or just a pretty piece of stand art.

[Z3n]

And it runs, and runs nicely:
https://www.youtube.com/watch?v=GMFcTmwPoIQ

Now, swingarm, gas tank, petcock, lights, gauges, controls, etc.