Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: Out of Order on December 24, 2009, 08:28:59 PM
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http://www.maxsled.com/absolutenm/templates/articles_layout.aspx?articleid=1059&zoneid=17 (http://www.maxsled.com/absolutenm/templates/articles_layout.aspx?articleid=1059&zoneid=17)
A KX250 engine with a exhaust valve driven off of the crank. Know it only needs semi-direct injection!!
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That's a cool design. Fairly uncomplicated. I've spent some time on the phone with Mr. Boyesen. He is not only a class act, he is very, very intellegent. He has an incredible understanding of 2T function, as well as 4T. If he designs something, it is usually worthwhile.
I hope he keeps it up.
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I'm very intrigued. While I love the idea of direct-injection coming in and saving the 2T from the grips of environmental hysteria, I am really reluctant to have a computer determining whether my bike is going to run or not in the middle of the desert. Who knows what sort of voodoo crap might happen in three years of down-time that might render the bike useless? Computers components tend to be on the sensitive side, and sitting in a 19 degree garage for months on end can't be good for it. And what's going to happen 20 years from now when I need it replaced? Who's going to provide gadgetry? Parts are simple enough, but that might just be asking too much. And there's no damn way I'd be able to fix it with a tool kit in my backpack.
I like Boyesen's thinking. Keeping the snowmobile and dirt-bike 2T engine purely mechanical is something I support 100%!
Hey Mad, you should do some of your string pullin' and get Mr. Boyesen to do a guest editorial for 2TMX!
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The technology is here guys...The problems is that the manufacturers/AMA want you to buy a 4 stroke!
Ski-Doo Rotax Challenge - Chapter 2: Cold Start Challenge (http://www.youtube.com/watch?v=N_DexODwAb0&feature=related#)
watch all the episodes!
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That's a direct-injection engine. It's a very good technology that I think has great promise, but I like the idea of solving the problem mechanically rather than using a computer-controlled injector. Both solutions are great! I can't stress enough how much I am in favor of the E-Tec technology, but I prefer the Boyesen solution.
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That is cool. But how adaptable is the technology to a competitive dirtbike? A snowmobile can wiegh 30-40 more pounds and it's not too much of a factor. Plus, they have the room to hang computers etc. I too, am not looking forward to computer controlled anything for off road. Or catalyzed exhaust. It's already here on 4T's. Next up...emissions testing. That pisses me off for more reasons that I care to name here.
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Engine Management (computers) have come a long way in the last 20-30 years. Plus they are a lot easier to tune than the old days of MS-DOS and Hex numbers, now its all graphical interface which is a hell of a lot easier to tune. But I'm still stuck between wanting to tune carbs or a efi controller. :(
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I'm more concerned with reliability. I don't want my dirt-bike, which is going to be taking heavy shocks and impacts for long periods of time, to be dependent on circuitry the size of a red blood cell. If I can destroy a piece of equipment in my computer by poking it with my finger, I'm going to be damn scared when a similar piece is installed on my bike, and I fall down on a trail.
That's not to say it won't work fine. Indeed, I've bought a totally digital helmet camera without hesitation, but I still have a natural preference for mechanical, rather than electrical, solutions.
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Then you can put this carb on it : http://www.cpcracing.com/site/256083/page/190735 (http://www.cpcracing.com/site/256083/page/190735)
$550 is a lot of cash though.
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Then you can put this carb on it : http://www.cpcracing.com/site/256083/page/190735 (http://www.cpcracing.com/site/256083/page/190735)
$550 is a lot of cash though.
First I have seen of this carb and I need to spend some time on their site but this is what I am talking about, except that looked like a 4 circuit carb! Which would be even better, but again, I need to spend some time on that site. The carb I use is a PSI "Big Air" carb. You can goole it. It's more money than the one you have listed but it WORKS, it can be tuned in less than 30 minutes and tuned up in less than 2 minutes.
I'll write more on it later.
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After a REALLY quick look...it appears to be adjustable EXTERNALLY, but has JETS. The "Big Air" carbs have no jets. That is a giant plus.
I'll read more later.
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PSI "Big Air" carb.
I knew I heard of that carb before, but I wasn't sure if it was on this forum or not. But I did find were I did hear about it.
http://www.ekartingnews.com/viewtopic.php?p=306232&sid=bfd9b7f2322c968affad7b55909238cd (http://www.ekartingnews.com/viewtopic.php?p=306232&sid=bfd9b7f2322c968affad7b55909238cd)
On the karting forum of all places!! :)
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Very interesting carburetors! I want to know more...
Mad, you put a Harley Carb on your bike??? How does it work?
The CPC carb looks very cool as well. Do you know if either of these are legal in AMA Pro Motocross??
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Both are AMA legal. They make non-Harley carbs. I'll find the link. The Harley carbs are fairly new. He has made good money replacing the OEM junk on the H-D with his carb. I'll write more later on the 3 circuit carb (prolly later tonight) as I'm preparing for a travel day today and it freaking snowed so now the Mrs. is in a panic (she has some "problems" with the way I drive!!!!! :o).
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Per your driving in snow, just show the Mrs. this video... she'll then think you are the best driver ever!
Wreckless Snow Driving (http://www.youtube.com/watch?v=80hOsx8Izfs#)
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The above video explains why Mrs. Mad Scientist does does not to ride with me in the snow. That, and I become somewhat verbal towards other drives who are driving 11 mph on flat ground, whilst their chains are beating the body off of their cars. I call them MORONS >:( ::) ;)
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Then you can put this carb on it : http://www.cpcracing.com/site/256083/page/190735 (http://www.cpcracing.com/site/256083/page/190735)
$550 is a lot of cash though.
I would say that this is a very close copy of this:
(http://up.picr.de/3638294.jpg)
(http://s1.up.picr.de/3638295.jpg)
(http://s2.up.picr.de/3638296.jpg)
(http://s3.up.picr.de/3638297.jpg)
(http://s4.up.picr.de/3638298.jpg)
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Lectron is the older company and the carbs cost less.
In January 1977 at the Toronto MC show,I had my stand right beside the LECTRON stand.
The rep for Lectron at that time was Kenny Roberts.We where sitting for 4 days together and he explaint to me the function of this unic carb.I did know about the carb because John Penton offered with his Penton bikes the stock BING or the Optional Lectron carb.But had no expirence with them.All I did know was that the standard BINGS on all our Zuendapps-Hercules-DKW-Maicos-Pentons,would only work when brand new,but had to be adjustet when a HORSE nearby farted.
On the end of the show,I handed Kenny a check for 10.000 Cad $ and he made me the very first importer distributor for Lectron.
And he gave me the CUTAWAY Lectron carb he had at the show.
I still have that carb in my office. ;D
(http://img683.imageshack.us/img683/6808/1004140c.jpg) (http://img683.imageshack.us/i/1004140c.jpg/)
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And he gave me the CUTAWAY Lectron carb he had at the show.
I still have that carb in my office. ;D
(http://img683.imageshack.us/img683/6808/1004140c.jpg) (http://img683.imageshack.us/i/1004140c.jpg/)
Now that IS a very cool story!
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Does anyone know if the Boyesen system is any different to Honda's AR system? I've checked, as much as I can, and can't find much on the Boyesen to separate it from Honda's Trapping valve set up they used on the EXP400 and the CRM250ARs that where sold, I think as late as 2000/01/02?
Yes, Honda used a partial 'diesel' system, with a combination of spark ignition & diesel/compression ignition ( I can't recall the order,low revs/ high revs, but understand that this can be applied either way), and I've seen no mention of this being used in the Boyesen engine, and, of course, the external nature of the trapping valve drive system is a result of it being an add on to an existing engine.
Is it fundamentally different to the Honda AR system?(of course it is, if its not using AR combustion - I'm really referring to the Trapping Valve concept) Have the Honda patents expired, and Boyesen have just taken up an engineering solution that has been left languishing?. Something tells me Eyvind Boyesen would perhaps be doing more than just refining the Trapping Valve, but I guess that's basically what he did with the reed valve, and the royalties paid by the factories that used the dual stage reeds certainly were well deserved - maybe, he's doing the same thing again, improving on the Trapping Valve and patenting those improvements?
When you see the variety of options available to the furthering of 2t development, be it DFI, EFI, AR, Trapping Valves, AST, FAST and the various combinations of these technologies ( and others ), it makes you wonder why these solutions haven't swept 4ts aside. It's sad & infuriating.
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Hey bearorso, there aren't many articles or pics of the boyesen engine out there. I don't know if there even done R&D or quit totally. The engine does look promising against say DI which is a new concept to motorcycles.
Honda's ARC has a (what you could say "big ass powervalve") that is controlled by an electronic stepper motor to move the valve to a precise degree in milliseconds. Now the Boyesen engine has a somewhat similar concept except the valve is a bit different and it is controlled off what we call the flywheel side via a cam system. They run a cam system because it is a timing system (look at the cam(s) on four
strokes) and can move the valve in relation to the crankshaft.
So, actually both systems are different from each other but with the same concept with the power valve. The ARC is just controlled by electronics, which can control when it wants to fire the engine with the spark plug or through compression. It's a fairly complex system, but it does work.