CB desert sled

Looks awesome!

Fantastic! The side-stand looks awesome.

Beautiful work! So what is the final weight of this beast?

Nice work Luke. Love you sharing the fabrication steps. It's really coming along!

A beautiful and sunny Easter morning, Luke hard at work early in the AM;



Later in the afternoon;



Luke has worked mega-hours on this beast, hopefully he will be rewarded with a great ride in Mexico!

How about another side stand for the other side... a split center stand if you will? Could be interesting and come in handy for flats... though a simple stick stand might be quicker and easier... It wouldn't be nearly as odd or creative...

A lot's been done recently, but not much of that was taking pictures. The projects left are getting smaller and smaller.

Here's one; cleaning up the wiring to the starter and stator, I wanted to figure out what gage to use. Lighter wire is much easier to route than the heavy stuff. So I measured the starter current. 80amps. Better use the thick stuff.






The rock guard (not heavy enough to be called a skid plate) was hopefullt the last of the big projects. Proving that the polishing wheel isn't just for carb floats:


Not the greatest mounting, but it will hopefully do:


I also added crash bars, they were NOS from ebay, but were for the 650 so a couple of the mounting points had to be moved. Otherwise they're great, and have three mounting points instead of 2 that most 500/550 guards have.



Rick and I rode for about an hour today, it was really good to get some time on the bike. It's running pretty well, just have a lot of tuning to do on it. And four days to do it in before going to Odessa. :eek1 I may be revalving the suspension in the campsite.

Luke came down to the coast today to do some jetting and other tweaking. I met him at Sandlake in case he needed any assistance. These two vehicles will hopefully be able to pose together again....on May 1st in San Jose del Cabo!





And here's a little video of Luke tearing across the flats wide-open. He was not happy with the top speed, so he might be doing some tinkering He hit just under 70 mph.

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Like OC posted, a little high speed testing today.

The handling was a little twitchy at first, but lower tire pressure and a little less preload on the rear shocks fixed that up.

It might be running a little rich:


Closer; dropping the main jets by a couple of sizes made it almost 10mph faster.



It just feels like it runs out of breath by 70, so something is up. I'll do a break-in service and then see if anything can be done about it. First up will be to replace the zig-zag air intake.




Parking in sand is easy. Un-parking would have been pretty hard if it weren't wet.




The beach is solid enough for the sidestand.

Flippin' awesome! The post jet-change plug color looks great and the 'sled looks right at home ripping among the sand...

No offense to the thumpers, twins and triples of the world, but as far as the sexiness per revolution ratio of dirt-bike engine noises go, the CBRZ-650 wins!

Looking good! Getting closer

Luke, I'm assuming you've done the math with engine rpm/internal ratios/final drive ratios/rear tire diameter? If so, you should have a number for how many rpm per mph? ( I heard OC loaned you a tachometer)

Air intake could definitely be a choke point and it seems like you've also got a ton of wheel-spin. :eek1

On another tangent, how fast do you really need/want to go anwyay??

Man, that thing sounds wicked - especially at the 14 sec mark where he punches it. That's just awesome.

Did you let youtube do it's "autostabilization" thing to your video? Maybe it's just me - but it makes it hard to watch. Feels like LSD flashbacks...

I agree about the youtube auto stabilizing thing...I need to upload it again without that crap.

You should be able to disable it without re-uploading. Just bring up the video while you're signed in and click on the magic wand looking thing under the video - it's called "enhancements". You should be able to disable it there.

I thought it'd be a good thing on most of my videos too, but it just makes everything look wonky. Now, I wish they'd stop asking me if I want to use it every time I upload a video!

Normally I don't like any inline 4. But that's easily the coolest one I've ever heard!

The Desert 100 is this weekend in Odessa, WA. Time for some seriously last minute prep.

First up was revalving the shocks. They are originally for an MX quad, so were really stiff. Anything rougher than packed gravel was a really harsh ride. I didn't take any pictures while I was working, so I'll steal someone else's:



This is from trxxx250r's rebuild thread on yfzcentral.com

The shocks are similar to ones I've rebuilt before except that they use a hypodermic needle to inflate and deflate the bladder. Of course I managed to stick the needle through one of the bladders. Since it was two days before the race the regiment voted for repair. I'll report later on whether tire patches hold on shock bladders.

I used a program called shimrestackor to help with the valving. It's worked pretty well for me in the past. Here's the rebound stack:



The program works with a spreadsheet. Enter the shim stack and the valve geometry and it will tell you how much damping force you get for different shaft speeds.

I didn't get much of a test ride on it, but it seems to work pretty well. Well enough that I'll probably dig into the forks before going back to the shocks again.



The timing was set wrong, was using the settings for a different sort of motor. The original timing was set to 35* full advance, and should have been 40*. The pickup plate needed to be moved and a new setting chosen on the ignition module.




A steering damper is always nice, especially reassuring when the chassis geometry is questionable. I'd made the mounting plate a while ago, today I cut the plate out for the arm and welded the post tower to the frame.




Check the headbolt torque. The first time I checked they'd backed out to around 1/4 the correct torque. This time they were all tight.


I got tired of looking in the manual to find the specs for the valve clearance, so etched them in the case under the valve cover.


A couple of the valves had tightened up, so will have to keep checking them often until they settle.


Last up was an oil change. Nothing special, but most importantly: no big chunks of metal. Lots of little break-in flecks, though.

Have fun!