CB desert sled

Expect me around late May.

Luke was so busy building and fabricating today, he forgot to take pictures!

Posting a few pics of his work today on the new sub frame, he can provide the narrative;

I had some help from another friend today. We measured, cut, measured, measured, filed, measured, clamped, clamped, measured,welded, measured, measured, cut, measured, clamped, measured, welded, measured, measured, bent, measured. (I'm getting a lot of use out of my big L-square.) And ended up with a rear frame part that belongs on a tube frame bike, not the pressed sheet frame that I've got. Oh well, better hide it with some black paint.


The stock shock mounts were in the wrong place and were the wrong size, so it seemed easier to just cut the whole rear part of the frame off and build a new one from scratch. It'l all cut up, but only two of the joints are welded so far. The top and down tubes were offset on the cross tube to make fabrication easier. That makes the cross tube weaker since it has more bending applied to it from the shocks than if the top tubes were further out. To compensate, it's much thicker than the other tubes. I'll make some spindles on the lathe to mount the shocks to and they'll get welded into the cross tube.


The big problem now is that I look at the bike and think about putting the gas tank under the seat and the air box over the motor. Putting 0 pound/gallon stuff up high and 6 pound/gallon stuff down low sounds nice. The question is if there's enough room and if it can be built quickly.

134 Days until race day. 19 weeks.

Plenty of time, if Kelly Johnson can design and build the U2 in 8 months you should be able to get this done in 19 weeks

I wonder if the 5 gallon plastic fuel cell from a Harley V-rod or the 5 gallon steel fuel tank from a Honda GL1100 would fit...

I think if we gave Luke an operation with resources like the Skunk Works, he could meet any deadline!

Jeebus Cory, don't encourage a lunatic.

The new sub-frame looks awesome. At this rate there is going to be about 3 original molecules of Honda left, but it's getting awesomer (not a real word, but entirely appropriate for this build) by the minute.

Look who's talking!

Tru dat.

Has your back forgotten the motor already? That's 3 very heavy molecules.

The Honda SOHC four, herniating spinal disks since 1969!

That's what titanium plates are for.
Just kidding

Not funny...
I just had a Ti plate in my neck go bad and 2 broken Ti screws. I had to have it all replaced last week after it failed.
Avoid that kind of mess at all costs. Almost cost me all ability to ride ever again and has cost me all dirt riding for 2.5 years so far and 6 more months ahead minimum.

I got some fancy new carburetors a couple of weeks ago, and of course the outlet on them doesn't match the inlet on the head. I could have bought adapters but they take up an extra inch of space that I'd rather use for the airbox. So it's time to do more lathing.

Start with some round stock that is just the right OD, so I only need to turn out the middle. The downside of this is that the parts are a little eccentric, just like the rest of the bike.


The stock was supposed to be long enough to make 4 spacers and has a little extra for clamping. It turned out to be long enough for 5; the four I needed and one screwup.

Start by drilling out the center so that a boring tool can go in.


Then cut out the middle to the right diameter

The spigots are 30.0mm OD, so this is a .1mm press fit. It felt about right. The final part I did was more like .15mm and it was a bit on the tight side.



Cut the part off:

Side note: using the parting tool this far from the chuck didn't work very well until I used the tailstock to secure the part.


Present the parts for inspection:


Press it on the spigot, with sealant:


One done, three to go.





As mentioned, I did screw one up. It would have been the last one but the cutting tool got dull and started chattering. By the time I figured out what was going on it had cut the part to 30.0mm which was a nice slip fit, but not a proper press.

Finally, fitting one up to the carbs.







All in all, a good warmup to the shock bushing spacers that need to be made.

Very nice; the spigots look great!

Dang...Keihin CR29s!

Never mind the CB - what's the Dog working on when it's not busy training you?

Lovely build mate.

Nu uh.

CR26s


Originally I was going to get CR29s, but there were too many reports of them sucking. The common theme was that the carbs were too big for the 550 and would go way lean below 7k rpm. The fact that most people run them with pod filters doesn't help, but still.....

Sudco recommends CR29s for the 550, and probably because they're the only US importer, everyone else recommends the same thing. Except for Keihin. You know, the company that actually makes the carbs. They recommend the 26s for mildly built 550. For a full-on race motor on a racetrack, they do recommend going one size larger to the 29s. For a totally stock 550 they recommend going one size smaller. Or would, if that size existed.

But anyway, that agrees with what the sohcforumites were saying, so I bought a set of 26s. I do already have a set of CV carbs that one guy said worked well; good performace, terrible fuel economy. But, it seemed like a lot of potential screwing around to get them working right. I'd rather spend a week screwing around with jetting than a month.

Thanks!


A couple of weeks ago he was working on a rotting deer carcass. Then sprayed it back all over the house and shop. So he's not allowed to roam any more.

He used to ignore me, I'd have to crack a beer to get his attention. Now he answers to my voice. Good thing, because cold beer isn't so appealing in a 40* shop.