Projects: NSR500

What do you get when you cross a Honda CR500 with a Honda NSR250?... Well, a Project obviously.







A gentleman named Chris from Kentucky decided to undertake such a project. The process is nicely documented on Jamie's NSR Homepage. I'll let Jamie deliver the results and conclusions, but I'll give a hint to any of you old enough to have owned 500cc two-stroke dirtbikes... You'll say, "no duh, that's why we all went back to riding 250's!" Still, I'm impressed. Chris did a good job finishing an interesting project. Another hint in closing, it's hard to top Honda's R&D department.

technology: two-stroke cousins

I was cutting some firewood the other day using a Homelite 240. It has an air-cooled reed-valve 40cc two-stroke motor & it does a fine job with average sized trees, provided I keep the chain sharp. But I got to thinking, “how much more power would this thing make if the little tin box of an exhaust system was replaced with a tuned pipe?”
(Manufacturer Advertised Stock H.P.: 2.16 SAE @ 8,000 RPM)
As the little saw cut through another round of pine, I pictured a custom pipe protruding from the saw. Then in a visual flash of memory I recalled pictures of an Open-Class Chain-Saw competition I had seen somewhere. And those saws did in fact have tuned pipes. So during the remainder of the afternoon my little Homelite morphed into an imaginary, custom, “one-off”, air-cooled-KX125-engine driven, 30 horsepower saw. One log later I had incorporated a custom radiator back-pack, (the battery powered fan drawing cool air in through the space created by shoulder & hip pads & the hot air out the back of the pack, away from me), with braided steel hoses carrying the coolant to my new upgraded water-cooled 125cc saw making 40 cedar shredding horses. Yup, I was way ahead of the competition!
That night I got online to do a little research and find a picture or two to share. I was blown-away by what I found!
First of all, 125cc air-cooled chainsaws are ancient news. Chainsaw manufactures have been making them that big and bigger for almost 60 years now. Sure, they’ve come a long way in displacement vs. power, but 1/8 liter saws are old, old news.
Second, folks making custom open-class chainsaws, called “hotsaws” have taken the sport and their creations beyond the limits of reason for quite some time now. Here are a few of my findings.

My favorite, (favorite for vision, execution, and relative practicality), is Gary Walwrath’s “hotsaw” named The Iron Horse . Here’s part of what Gary has to say about his crazy creation;

“Over 600 hours of computer design time, and a year of fabrication, fitting, assembling and testing, the (IRON HORSE) was ready to kick some butt.

"We bought a brand new 500cc Husqvarna Desert Racer motorcycle. Removed the motor, cut off the transmission, reversed the crank shaft, built new outer case covers, designed and built our own electrical system and a million other things. When it was all finished, the saw was a work of art. We had red anodize side plates, polished aluminum mounts, custom Handles etc., etc.

"The fuel and bar oil, and coolant was pumped from a life support system through plastic tubing that hooked to a manifold mounted on the saw. The life support system was mounted on a separate cart with wheels. The liquids were pumped using air pressure. The coolant used an electric water pump. The saw was started with a detachable 24 volt starter motor...”

So it turns out that my imaginary water-cooled 125 wasn’t even close to par with Gary’s 90 horsepower beauty. I was in way over my head before I even began!

Then my research revealed the just plain silly:

Like this Harley engine chain saw. Harleys are certainly not known for their horsepower to weight ratios: something worth considering in a hand-held tool. And Harleys certainly are known for their vibration to power ratios: something worth considering in a hand-held tool. But my beloved grandmother always said that if you can’t say something nice then don’t say anything at all. Hmmm... Well... Harleys are competitive in flat-track... Oh, and “Chicks dig ‘em” (At least some do). Ok, moving on.

These guys from Washington felt that weight was no issue for real men, and anything under a couple hundred horses just wasn’t worth messing with.

So after warming up with a nitrous burning V6 that they yanked out of a Ford Ranger, they went on to create “the Predator”. (Yes, when you start naming your saws you know you’ve made the big time!).
The Predator, Aluminum block 215cid (3523cc) V8. Weighs in at 507lbs.

Ok, I’m out. Shut down before I even began. I guess I lack the back, the belly, and the balls to run with these guys. I’ll be out back with my 10 pound, 2 horse Homelite daydreaming about some other niche. Perhaps my girlfriend summed it up nicely; “Some people have too much time on their hands”...

People: LaRocco Hangs it Up

So I read that LaRocco is retiring after this 2006 Supercross season. I was surprised, for I somehow just assumed he’d go on forever. Oh I’m sure he’ll be around for a while. Maybe he’ll race Red Bud each year. He should have no problem earning the points to keep his Number 5 for quite some time. It’s nice to see Doug Henry cruise around with his Number 19. It’s even better to see him move on to other genres and do quite well. Supermoto, GNCC, LaRocco could win races. Flat-track, roadracing, Mike could have fun. And if “the Rock” wanted some part-time work, the industry appreciates such vets and is happy to pay for their knowledge. If he was interested, he could certainly have a post riding motorcycle career such as Ricky Johnson (I’m old enough he’ll always be “Ricky”, unless Honda hires me, then it will be “Mr. Johnson, thank you sir”), or Jeff Stanton, or the Man himself, Mr. DeCoster. Yes, hopefully Mike LaRocco won’t just disappear. But with his son’s apparent desire to follow in Dad’s roost, he’ll be around for a few more decades.

See, it’s not just that “our” sport needs the image of dependable every-day people. It’s that in a world where 21 years old is seasoned, 25 is over the hill, and 35 is ancient, guys like “the Rock”, Doug Henry, Guy Cooper, and Doug Dubach provide inspiration and perspective to us “ancient” riders. If MY back hurts after my amateur career, then I KNOW the Rock’s does. In fact, I bet his knees hurt, and his ankles hurt, and his wrists hurt. And if he can jump those triples, and strafe those rockers and beat almost ALL of those kids, then maybe I shouldn’t be such a wuss on my YZ. And yeah, I’m going to start running again! (Next week. After all, I have 3 years to train before I’m old enough for the Old-Timers Nationals).

Looking for a few facts about LaRocco’s career I went to the Motorcycle Hall of Fame web site. I had to look twice, incredulous that he isn’t in the hall of fame. Tonight’s race in Indianapolis would have been his 230th Supercross start. (A record I believe). But he was injured in practice and didn’t race. Still, records or not, the Rock is a cornerstone of modern motocross (sorry, the pun was necessary) and deserves to be in the hall of fame.

technology: "6-stroke" engines (or "Jammin Jimmy and the Desmodromics")

Remember in Thermodynamics, they had you calculate efficiency of Diesel engines using a formula for Fixed Volume conditions? Of course, thinking that your sharp mind and fresh insight had found a fundamental flaw in the theories of Thermodynamics thus winning you riches and public acclaim – or at least some much needed extra credit on the next exam, you pointed out that the volume of a piston engine changes. But they said that the “explosion” happens so quickly & the Diesel engine is spinning so slowly that we can just consider the engine working under Fixed Volume conditions. Ok, so it wasn’t a coup de physics, but at least the equations worked reasonably well...

Well, last night I was dinking around online, curious about how ceramic pistons are coming along these days, and I came across an article by Ducati Motors. Yes, the fine folks who brought us Desmodromic Valve Actuation have come up with another creative engine innovation...

To greatly simplify things, their internal combustion engine uses a “crankshaft” that’s more like a camshaft. So since the “connecting-rod” is not attached to a crank that’s arcing circles, they can end up with a piston that essentially stops at TDC for a relative while as well as at BDC. They’re calling it a “6-stroke” engine, for the piston can hang-out at TDC & BDC long enough to accomplish things.
How does this make for more powerful and efficient engines?
Well, for one: As the piston is sitting at BDC the exhaust valve opens, and the gas’s residual pressure (as well as the exhaust system’s scavenging effect) moves some of the mass of gas out of the cylinder. When the piston begins to move back toward TDC less of the flywheel energy is used to evacuate the cylinder.
And two: In a similar energy saving situation, when the piston moves to TDC during the compression cycle, the ignition timing does not need to be advanced, since unlike a regular piston engine, the “6-stroke” engine’s piston will be sitting at TDC for a bit while the gasses are burned. With the timing NOT advanced, no flywheel energy is wasted by the increasing pressure of gasses burning before TDC.
And it gets even better! Since they’re not relying on a circular crank that would dictate that their piston move in a sine-fashion, they are much more free to dictate how and where the piston moves and accelerates. This opens a whole new door to engine tuning!

So send your old stuffy Thermo professor a card. Better yet, send him this link. He might even smile... And point out that this “6-stroke” engine might have more issues regarding heat-transfer to engine parts, and more “blow-by” the rings. But then you could tell him that the rings are theoretically perfect, so shut up & just do the math! Oh, sorry, just my little fantasy there...

RC/Suzuki Fuel Penalty

Wow! I was sure surprised to read on Racerxill.com that Ricky Carmichael’s Team Makita Suzuki Racing was busted for running illegal fuel at San Diego. And a 25 point penalty! That’s huge! That’s like a DNF. (See St. Louis, 18 Feb 2006. )

But just as I was starting to feel sorry for RC... (I mean, I seriously doubt he masterminded a cheating scheme and convinced his crew to cut corners; “Aw come on guys, it’s the only way I can beat anyone”, yeah right) I remembered his remarkable salary for riding yellow bikes. He’ll be ok folks. We don’t need to start an RC charity fund quite yet.

American Suzuki issued a press release: “...The fuel used by the Supercross team at the San Diego round was supplied by a third-party vendor and was not tested by Team Makita Suzuki technicians before the race...”

Speaking of how Suzuki is spending several million dollars per year to have RC ride their bikes, maybe they should spend a couple bucks to have their fuel tested before each race. I’m not a corporate race-team bean-counter, but it seems like cheap insurance on a huge investment to me.