Post by: 250300 on August 06, 2013, 04:39:20 AM
It's quite well known that in the mid nineties honda were racing a Single Cylinder 400cc Baja / Rally bike.
It was the Honda EXP-2 400cc ARC...it could be ran using either a carb or fuel injection.
This bike won it's class and came 5th overall in the Dakar Rally.
There was also the honda CRM 250 AR Prodcution bike (Japan only).
http://www.honda.co.jp/factbook/motor/CRM250AR/199701/
There was the 02-07 CR250 motocrosser that had a servo controlled exhaust valve and was case reed inducted just like the above bikes.
It could clearly be seen that they were trying to move in a different direction with the servo operated valve on the CR250.
This is all very interesting but I found something I hadn't seen before.
It was an online book / pdf about engine technology and in it was a paper from Honda R&D.
They have experimented successfully with AR technology but they also did this in combination with PDI (pneumatic direct injection).
They had this technology working at the beginning of the century if not earlier, who knows what they had planned for the two stroke motorcross line had the four strokes not come along.
I think this shows that if two strokes do make a real comeback then Honda have the tech ready and waiting!
They're just a sleeping giant.
Post by: LukeG on August 06, 2013, 05:37:16 AM
There's an American company Ecotrons that sell EFI fits for bikes and other small engines. They have a 2T kit which run two injectors in front of the throttle body. I look at them once a month or so and think....?
Post by: factoryX on August 06, 2013, 07:27:34 AM
Post by: Stusmoke on August 06, 2013, 08:01:15 AM
If i may reference another thread, the one that had the magazine article about what some of the factory teams thought of the FIM 300cc two stroke championship coming next year, you guys know the one. The Honda fellow, roger someone? claimed that Honda went four stroke because of environmental issues and couldn't do two strokes and be environmentally friendly at the same time... Even though they had this bike functioning with EFI about 8 years prior to their first CRF450R release.
Post by: TMKIWI on August 06, 2013, 08:40:12 AM
Honda could have released a clean burning 2 stroke but decided it was much easier to promote 4 strokes as it was an easier sell.
i.e , Everyone has a 4 stroke in their car,van,lawnmower etc.
Bull**** reason but true.
Post by: Uniflow on August 06, 2013, 10:32:49 AM
TM the YZ will be at Epic Events this week end, see you there? Saturday.
It's got a new toroidal head. Haven't tried it yet.
Post by: SachsGS on August 06, 2013, 03:49:27 PM
Post by: LukeG on August 06, 2013, 11:12:04 PM
Post by: factoryX on August 06, 2013, 11:14:09 PM
Post by: LukeG on August 06, 2013, 11:18:55 PM
Just imagine if old man Honda didn't hate two strokes so much, where we could be!
Post by: factoryX on August 06, 2013, 11:23:29 PM
Post by: LukeG on August 06, 2013, 11:34:06 PM
At the time Honda were the main voice in calling for the introduction of four strokes in racing, citing environmental concerns as the driving force, which most of us know to be utter BS.
KTM claimed to have tried FI on thier 250 GP bikes but found it to be ineffective compared to carbies and made thier bike unreliable. I wonder how hard they really tried.
The push to phase out 2Ts started in the mid 80's mainly driven by Honda.
Post by: factoryX on August 06, 2013, 11:56:40 PM
Post by: 250300 on August 06, 2013, 11:58:09 PM
Post by: 250300 on August 07, 2013, 12:32:09 AM
Post by: Stusmoke on August 07, 2013, 09:58:25 AM
I think weight and extra cost concerns are whats holding back injected 2T. An extra kilo or two of weight plus the whole mystery surrounding fuel injection and the fear it puts in most people. I would love to see direct injection introduced on all bike motors, from MotoGP down to 50cc fun bikes. Development of smaller and lighter components will only come through R&D but govening bodies need to change the rules to allow direct injection to be used in racing. I have been looking at whether or not I could fit an injector into the head of my DRZ. I have CAD models of several of my employers engines which have direct injection and believe it may be possible. The hard part will be setting injector timing. It's still on the one day list.
Peoples fear of an extra 2 pounds and some complexity on their two strokes isn't whats holding it back at all, its the fact that there is simply no demand for an E/DFI system in a two stroke dirt bike. Lets look at KTMs sales of two strokes: The dealership I got my 2013 250sx from (QBfour toowoomba) has gotten in a 2014 300 exc, 250sx and 350SX-F, guess which two were already sold before they were on Australian soil?
I promise you that if KTMs 2 stroke dirt bike in general sales were nigh on non existent this year and someone made a forum where everyone went and said they didn't buy it cos it was carbed, 2015 would see injection of some sort. Kinda like we bash Honda on here
KTM has said it again and again, its because there is no demand. Its a catch situation because you can't get the injected two stroke (yet) but you don't want a four stroke either. As of 2014 YZ250F release, there is not a single carbed four stroke MX bike anymore. That leaves you with the carbed two stroke, whether you like it or not. Or, do as Uniflow suggested, MYO!!!!!
From a recent article KTM supposedly has fully operational FI 2 strokes, but they stated it would make the bikes to heavy and to expensive oh and the best part, unreliable(And the EFI 4 stroke aren't)!
KTM's very clever in saying that. We all know for a fact that its not true and KTM knows it too. Well it might be true, but it doesn't HAVE to be an unreliable system. But if the more they put people off the idea of an injected two stroke, the more they sell their carbed two strokes and the higher props their injected four strokes get. Its smart business.
Post by: bearorso on August 09, 2013, 02:24:03 PM
It's an interesting design but the forced air induction make the bikes illegal to race. Although Honda have a way of getting thier own way nearly all of the time...
There's an American company Ecotrons that sell EFI fits for bikes and other small engines. They have a 2T kit which run two injectors in front of the throttle body. I look at them once a month or so and think....?
It is no more "forced air induction" than Any EFI / DFI set up out there, on most cars, trucks and bikes. There is pressurisation, through a variety of means, of any Injector unit. The main air charge comes in through the reeds, into the cases. Though, the base drawing does make me think that it may have had an 'air purge' arrangement to it. The earlier EXPs, ran with carbs, and an engine that was very much based on the architecture of early 500s. Then, as can be seen in those pictures, it became something quite unique. The CRM250ARs, ran with a carb. And you can find them in the various bike classifieds here in OZ, pretty easily.
It's conceivable that the entire fuel / air charge could be delivered purely by the injector unit on an ICE unit, but it's almost completely impractical, and truly complicated and expensive to do so on a bike. The sort of expensive, complicated and heavy, that so many people are scared of - and, in that case they'd be right. But, it's not something we really need to 'worry' about.
DFI / Whatever Clean Tech, that companies have, is in road going 2ts future, simple as that. The date, now appears to be 2017 for us to see it, if that remains the Euro
?? standards introduction. I'd like to see it sooner, though.