CB desert sled

The triples and stem are stock DRZ parts. The bearings were replaced with different sizes to match the Stem and Headtube. The diameters were off requiring different bearings but the height of the stem was about perfect for the CB head tube. The steering stops even lined up.

I got the bearings from All Balls Racing. They have lots of information on sizes for fork swaps, and lots of different sizes of bearings.

Swingarm madness.



As mentioned, the rectangular tubing sprung open when cut. Welding the bevels on to it was a little trickier than planned, but it worked out.







Crap picture, but it's glowing metal.




Stick welds are not subtle.



A scrap that I welded and cut up to check penetration.




More welds, this one with the slag still on.




Measure twice, cut once. Measure 10 times, weld once.



Adding some posts so that the cam snail adjusters will work.


They're a 'tap' fit. These are actually just placeholders. The final ones will be eccentrics that will be adjusted to make the snail positions match, then welded into place.




I put the camera down for a while, and when I picked it up again I had this:


I'd guess it's half done at this point. The cross brace needs to be welded in, then the mounts for the shocks, brake, chain guide and sliders.

Subscribed. Man really like this build. Thanks for the report!

Sorry I didn't stop by last night, Luke. I didn't leave from working on my "project" til after 9pm and you were long gone by then. Quick question, what is the weight difference between the modded swingarm and the stocker?? BTW, looks like you're getting pretty damn good at welding Wanna build a roll cage?

Subscribed! Excellent work, I'm in awe!

Awesome Luke, it's looking great! You've definitely gone where Honda SOHC CB650 swing arms have never gone before!

It appears as if the time to order a set of shocks is drawing near...

I'm glad everyone is enjoying the thread.


The scale says that it weighs a bit under 20 pounds. I'm not so sure about the scale, it feels heavier than that. It's similar weight to the DRZ wheel, so not totally out of line. It's much heavier than stock.

Just trying to spread the axle mounts it's clearly a lot stiffer than the stock one, and that's in its weak direction.

I think that time passed long ago.

What's the project management rule? Take the schedule and double it.

A few more pics of Luke's swingarm madness;

Subscribed! My first bike was a '76 CB550, and I dreamed of doing something like this. Awesome to see it happening!

Holy Mackerel! I've been away too long! That looks killer. My schedule has been crazy, but I'd love to get back in the shop with you. Looks like things are moving along...

You'd better hurry, or I'll finish it without you.





I got some more done on the swingarm this evening.

First up was to weld in the cross brace. This didn't work out quite as hoped. It welded in great, but it pulled the arms together. So now the swingarm is just wide enough to work with the DRZ wheel, but without any spacers. The sprocket fits so I may leave it alone, or I may cut and spread it if there are any other clearance issues.

A stock 550 swingarm is included for scale:






The weigh-in:

20 pounds. Stock is 10, the frame is 30. Ouch. At least it's stout.



Time to install it:



Check the sprocket locations; it looked about right.


Good thing I cut the wedges off the front of the swingarm. The chain should just graze the guard.





Finally, starting on checking the shock length.

So the swingarm will be the strongest point on the bike

And the heaviest....:eek1

It does look pretty damn sweet, Luke.

Nice looking build.

So awesome... I'm digging the snail adjusters vs. the standard Honda adjusters; very nice!

With a swing-arm this stout, frame-bracing in the works and the thermostat-like power from the 650 four, I expect wheelies... lots of wheelies!

Huge progress the past couple of days.


Alex came over to help out, we did some lathing.


Danny and Larry supervised.






I had some new sprockets from PBI that I was going to cut down. No such luck. They were a lot tougher than the stock sprocket was. The carbide barely touched it.


The angle grinder wasn't doing much either.


I'll have to try something else.


We also modified a tool holder to work on the big lathe. Of course, we used the lathe to do this.

Centering the part in the chuck:



Drilling out a hole. It seems weird, holding a drill bit still and turning the part.




Cutting a shoulder. The steel bits weren't working on the steel part at all. The carbide bit cut right in.





And, so we could say we did some actual work on the bike, we

cut


the


frame


in



half




A good day.

I found these on craigslist. They are from a YFZ450R quad, and are just the right length.




Another 20 pounds. This bike is porking up pretty quickly.

Having cut the frame apart, it's time to put it back together. I'm spacing it out 2". Actually, it's 50mm. I'm driving Rick nuts because he thinks in inches and I keep talking to him in metric.

To review, supposed advantages are:
Lower center of gravity.
Better swingarm pivot geometry and chain slack.
Better footpeg-exhaust-frame-skidplate relationship.
Easier R+R of the motor.

We'll see.



First thing is to make a bunch of spacers and sleeves. The sleeves go inside the spacers and frame tubes. These make both the alignment and welding much easier.




I started with some test welds. This is the first time I've used this TIG welder, and it's been a long time since I've used one at all. Fortunately the setup seems to work fairly well and there's a lot of range between getting full penetration and burning through.


The TIG setup is pretty basic. The argon goes to the torch, and the stick welder clamps on to the same adapter that the argon goes to. There's a valve on the torch for the argon, and the power is always on. There's no auto start, so it has to be scratched like a stick electrode to strike an arc.









I'm only extending the four main tubes, the rear tubes for the shock mounts are probably going to be completely replaced. The sleeves are tack welded in place. The front tubes have the sleeves in the frame, the rear have the sleeves in the spacers. This is due to the different diameters of the tubing. There are four different sizes involved here.


I assume the rust around the weld means I should be using a bigger cup on the torch?












Rick came up with a great way to get the alignment right.




With this much progress, it was time for another mockup and pose.