direct injection


60 replies to this topic
  • why_zed

Posted October 21, 2008 - 11:12 AM

#21

pro's are sometimes our example. They all ride four strokes....


Really???

  • why_zed

Posted October 21, 2008 - 11:30 AM

#22

Lets pretend someone does introduce the new super 2 stroke engine. How long would the AMA allow it to be dominate?


Well believe it or not, we all don't live in the ama and "most" of us use our bikes for fun and race for fun.
Most of the ama pros don't buy their race bikes, they will ride the most expensive advantage that the sponsor brings to the track..
The pros that buy their own play bikes often buy 2 strokes.

Why just last weekend Sean Hamblin showed up at a cherity event on a YZ250 and heard (I wasn't there) that he ran ahead of the 08 canadian champ on a 450..

Broken record,, The 4T domination is the cc advantage. Broken record,,
Broken record,, The 4T domination is the cc advantage. Broken record,,

  • harrperf

Posted October 21, 2008 - 12:04 PM

#23

Manufacturers have to pick one or the other... cost too much with tooling and R&D to make two of every class.

I am a huge advocate of the two stroke. It's a better bike in the big picture when you factor initial cost, maintenance costs, used bike costs...etc....

The four stroke has sent the sport downwards, local turnouts across my state have gone down....it's sad. Ask anyone who rides hard if they would dare buy a used four stroke. That's a joke, they wouldn't even consider it.

that site eternaltwostroke touched well upon it in some of it's posts....and I think that two stroke militia site is cool too.

Ask yourself why two strokes were regarded as the best choice and you will arrive at this answer. If the rules said you are allowed 125cc's of whatever motor you want, no rules, no regs other than that, what would you choose?

That's why two strokes became popular. Then the handicapping came in....logic dictates that if you fire every other stroke you need twice as much displacement to be fair. So way back when they allowed twice the displacement...because is was logical.

But sadly they didn't account for Volumetric Efficiency etc....and the two stroke eventually fell with the rising technology that allowed fourstrokes to become lighter and lighter.

For those who feel the two stroke powerplant can be developed more than it is....think again. It probably reached its peak mid 90's if not earlier! Much of this has to do with how a two stroke gets its air (all engines are just big air pumps) There is only so much area available on a two stroke per given bore size to get air in (Pi * Bore * port height - and port height is limited to powerband). Direct injection is really cool!

Also, not touched upon, is fuel injection in the typical sense. It makes big gains in rideability and performance as well....carbs are not equiped as well to handle the back/reverse flow that happens in two strokes as fuel injection.

I spoke recently to a guy who developed race 125 engines for motogp for 15 years.....and he said fuel injection is big gain. Also, tying that in with an electronically controlled powervalve to match up to the system can make the bike entirely different!

But the manufacturers decied four strokes, and that is what we get.

To elaborate on what pro's ride, a good friend ran into Ivan Tedesco a while back when the pros were switching over and he said he didn't pick the bike...his team did....so he had no choice in the matter.

Pro's are pro's, fast on anything.

  • RCannon

Posted October 21, 2008 - 02:28 PM

#24

Well believe it or not, we all don't live in the ama and "most" of us use our bikes for fun and race for fun.
Most of the ama pros don't buy their race bikes, they will ride the most expensive advantage that the sponsor brings to the track..
The pros that buy their own play bikes often buy 2 strokes.

Why just last weekend Sean Hamblin showed up at a cherity event on a YZ250 and heard (I wasn't there) that he ran ahead of the 08 canadian champ on a 450..

Broken record,, The 4T domination is the cc advantage. Broken record,,
Broken record,, The 4T domination is the cc advantage. Broken record,,


Your total right without question. However, the AMA has basically directly controlled motorcycle development since god knows when.

Go into a motorcycle shop and look at whats available . Other than the cruisers and some atv's, nothing is especially made for us..the average guys who purchase the bikes. We get models that were produced for ama racing. Look how the 750 streetbike class died when the rules changed. I think Suzuki may be the only ones left who still offer a modern 750.

Like it or not, we end up buying whats available. The only way we get a shot at a 2 stroke 300cc motocrosser with direct injection is when someone plays by its own rules (maybe ktm) or the ama writes a new rule.

  • r_thump

Posted October 21, 2008 - 04:50 PM

#25

Yea Yea but when things get tough pros choose 2t. What about Endurocross, the Erzberg Rodeo, Last man standing, ISDE they were all won on 2t KTM 300xc. Also in OMA races and in the WORKS races when things get nasty the pros choose to ride the 2t ounce again. In Endurocross the leader in points Teddy Blazusiak uses a 200cc 2t. Come on if you love 2t go 2t, there is still lots too choose from especially from KTM Husqvarna TM and Yammi. I think that supercross is cool and flashy but enduro style races are gaining ground and if you give it a little time maybe 2t will rebound. PS. Dirt bike mag nominated the ktm 300 xc the best off road bike of all time, ounce again a 2t.

  • 1.21GW

Posted October 21, 2008 - 04:59 PM

#26

DIY FI system:
http://www.bgsoflex....megasquirt.html

I'd done some reading there and else where thinking about DI 2 Stroke. Its very feasible, quite a few technical papers have been written on the subject by SAE Engineers. Like mentioned previously quite a few outboard motors already equip with it from the factory.

A DIY DI 2 Stroke retro fit would be to costly to be even close to widespread. All the different bikes would require quite a bit of tweaking. All in all i hope that we someday could get a 250/300 DI 2 Stroke from the factory but it just doesn't seem like its going to happen. I'd buy one....well if it wasn't 10k like bikes seem to be approaching.

  • aggiemoto99

Posted October 21, 2008 - 05:03 PM

#27

DIY FI system:
http://www.bgsoflex....megasquirt.html

I'd done some reading there and else where thinking about DI 2 Stroke. Its very feasible, quite a few technical papers have been written on the subject by SAE Engineers. Like mentioned previously quite a few outboard motors already equip with it from the factory.

A DIY DI 2 Stroke retro fit would be to costly to be even close to widespread. All the different bikes would require quite a bit of tweaking. All in all i hope that we someday could get a 250/300 DI 2 Stroke from the factory but it just doesn't seem like its going to happen. I'd buy one....well if it wasn't 10k like bikes seem to be approaching.



Expect a kit to surface in two years or less I bet! People are working on it, but the market is one you can't expect to make money in...not a lot of people have two strokes now, and the ones that do are usually happy with current performance.

  • RCannon

Posted October 21, 2008 - 05:23 PM

#28

A kit would be really fun. I dont see myself buying one (for the exact reasons agiemoto specified) I cannot complain much about my yz carb (except when I remove it) and if the throttle response improved, I would need that new brown seat cover made by the depends company.

I think the economy destroyed any chance of a new, improved two stroke. The only 09 bikes that I cannot find locally is a crf 450...or yz 250. Most shops are sitting on plenty of 2007 and 2008's.

I think a lot of people were using their house money to finance motorcycles....

The most exciting thing about a NEW 2 t would have been the weight reduction. Imagine Yamaha taking the yz 400 from 250 lbs down to 230 in basically three years. What could they have done with a yz 250?

  • aggiemoto99

Posted October 21, 2008 - 06:32 PM

#29

A kit would be really fun. I dont see myself buying one (for the exact reasons agiemoto specified) I cannot complain much about my yz carb (except when I remove it) and if the throttle response improved, I would need that new brown seat cover made by the depends company.

I think the economy destroyed any chance of a new, improved two stroke. The only 09 bikes that I cannot find locally is a crf 450...or yz 250. Most shops are sitting on plenty of 2007 and 2008's.

I think a lot of people were using their house money to finance motorcycles....

The most exciting thing about a NEW 2 t would have been the weight reduction. Imagine Yamaha taking the yz 400 from 250 lbs down to 230 in basically three years. What could they have done with a yz 250?


What ktm did with theirs! It's extremely light!

  • RCannon

Posted October 21, 2008 - 07:39 PM

#30

What ktm did with theirs! It's extremely light!


Exactly that. Or maybe even something more dramatic. If Yamaha shaved almost a pound off the rear wheel for 2009, how much could have been saved from a new yz 250 engine, or frame?

I believe I would be more inclined to buy a 200 lb yz 250 vs a 220 lb direct injection model. Hell, who am I kidding. I love my current bike, but the checkbook would come out if the 2010 yz weighed in at 200 lbs....carb be dammed!

  • aggiemoto99

Posted October 21, 2008 - 07:43 PM

#31

Exactly that. Or maybe even something more dramatic. If Yamaha shaved almost a pound off the rear wheel for 2009, how much could have been saved from a new yz 250 engine, or frame?

I believe I would be more inclined to buy a 200 lb yz 250 vs a 220 lb direct injection model. Hell, who am I kidding. I love my current bike, but the checkbook would come out if the 2010 yz weighed in at 200 lbs....carb be dammed!


hahaha. I second that!

hell 20 pounds is about 2.5 hp in a straight line...putting the bike on par power to weight of a 450.

Not to mention how sweet it would be to throw it around even easier! I bet they could do it if they wanted....but they dont want to.

  • bay area mx1

Posted October 21, 2008 - 07:56 PM

#32

I have a source inside Yamaha and I was told this:
Yamaha is set to release a 2T DI streetbike which will be a re release of the RZ350 back in the day...It is going to be direct injected, displace approx. 350cc put out about 75-80hp and be street legal and cleaner than a modern 4T...Think about this logically...This bike would cost less to produce, less to maintain, put out more power per cubic inch than a 4T, get excellent gas mileage, and get tons of sales from loyalist 2 smoker riders and people that had an RZ350 back in the day...When this bike is released, expect a DI YZ250 to follow very shortly..I know I will be on the waiting list as soon as its announced...

  • bay area mx1

Posted October 21, 2008 - 07:59 PM

#33

http://www.motorcycl...08_2strokes.htm

  • 2 stokes for life

Posted October 21, 2008 - 08:08 PM

#34

Looks like a Banshee engine with DI. I would be first in line to buy one of those.

  • aggiemoto99

Posted October 21, 2008 - 08:41 PM

#35

I have a source inside Yamaha and I was told this:
Yamaha is set to release a 2T DI streetbike which will be a re release of the RZ350 back in the day...It is going to be direct injected, displace approx. 350cc put out about 75-80hp and be street legal and cleaner than a modern 4T...Think about this logically...This bike would cost less to produce, less to maintain, put out more power per cubic inch than a 4T, get excellent gas mileage, and get tons of sales from loyalist 2 smoker riders and people that had an RZ350 back in the day...When this bike is released, expect a DI YZ250 to follow very shortly..I know I will be on the waiting list as soon as its announced...


I am buying the first hundred they make! hahaa if only I could! I pray they do, it's bar far the coolest thing to happen in a long while!

  • RCannon

Posted October 22, 2008 - 04:01 AM

#36

I hope it sells better than the original in 83 and 84. Even the Kenny Roberts replica went for discounted prices. I know they are cult bikes now, but back when they were no big deal.

  • snoop76

Posted October 26, 2008 - 08:27 AM

#37

http://www.motorcycl...08_2strokes.htm


if that bike is supposed to be a drawing of their DI RD350, then why did they draw it with a carb???

  • jbusa8

Posted October 26, 2008 - 01:06 PM

#38

PS. Dirt bike mag nominated the ktm 300 xc the best off road bike of all time, ounce again a 2t.


and DirtRider called the KTM 250 XC the best ever.
not a thumper folks.....

  • studboy

Posted October 26, 2008 - 01:57 PM

#39

If Yamaha does come out with a DI 2T that runs well, I will buy one for sure.

  • RCannon

Posted October 26, 2008 - 02:09 PM

#40

I bet I would be on the buy list as well. No way would they produce one now without making it lighter. Not that my current bike is heavy or feels heavy. I think the yz 250 feels more 125 like than anything I have ever ridden.....However, can you imagine 200 lbs and 45 hp?????...maybe evn more hp with a new direct injection.





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