Honda AR PDI Two Strokes

[250300]

I was doing a bit of reading and came across something interesting.

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.

[LukeG]

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....?

[factoryX]

Yes we've all seen it, and regret the fact it does not exist today never mind the design is locked up and patented by honda aka the leading tech in two strokes lmfao, how very unfortunate..

[Stusmoke]

Yeah it got posted up a couple months ago, but thanks for posting it up again, particularly the diagram. It just goes to show how bogus everyones "technologically advanced" four strokes are. Only reason there aren't E/DFIed two stroke dirt bikes pouring out of the factories is because they don't want it just yet. Despite the fact that in the golden motocross age (aka two stroke age) bike sales were almsot what? 10 times what they are with these super awesome four strokes...

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.

[TMKIWI]

Welcome to the corporate world.
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.

[Uniflow]

Make your own! Don't bother with the big guys, if they don't want to play, who cares.
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. 
 

[SachsGS]

I admire Honda for the effort they put into these two stroke designs but I sometimes question the "direction" Honda has taken. If we look at the Vtech 4T platforms you have to appreciate the complexity but a similarly sized turbocharged motor achieves more with less. With that in mind, if you were a small start up 2T manufacturer would you design a powerplant using Honda's technology or try something similar to the Skidoo/Rotax DI system? My money would be on the DI, once again you achieve more with less.

[LukeG]

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.

[factoryX]

1 kilo AKA 2 lbs is nothing. Throttle bodies are actually lighter than carbs..

[LukeG]

That's one of the main excuses KTM is using for delaying the release of thier FI 2T. I agree though the potential benifits would out weigh the negatives and like I said with a few more years of real world R&D in racing the systems would be greatly improved, become smaller and lighter, more reliable and hopefully bring 2Ts back into the fold.
Just imagine if old man Honda didn't hate two strokes so much, where we could be!

[factoryX]

The negatives are almost non-existent and are merely an excuse, look at Uniflow's build and tell me its not doable? He's just tinkering around the shop, imagine what they could do at a manufacturing level if they haven't already and are simply holding out(Which is the most likely scenario). KTM stated that it would make production more expensive and bikes more heavy, my-ass, then why do all their 4 strokes have EFI??

[LukeG]

I totally agree it's doable, they just don't want to because it would most likely render all of the money they have spent of four stroke development wasted and it would make them look stupid. I love Uniflows bike and would love to get his help to do a similar build when I get some time and money.
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.

[factoryX]

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)!

[250300]

A patent image from honda;

[250300]

Honda reverse cylinder pdi quad bike engine;