Direct Injection - for and against

[Chris2T]

Thought i'd add some thoughts to Jim's posts. My responses are in bold

Hello Everyone,

I can only speak for myself here, but I don't want a direct injection 2 stroke UNLESS it's going to make something available to us that we don't already have. We don't have any road-going 2 stroke street bikes with greater than mid-80's technology. Most with mid-70's.
If it means NEW RD350's, RZ350's, S2's, S3's, H1's, H2's, Suzuki GT's instead of GS's and things like that, then I'm probably into it, until I have the opportunity to buy one of the originals. If all we'd be getting out of it is more homogenized versions of what we have already, then forget it. I've heard that D.I. makes a 2 stroke run a little more like a 4 stoke... That's all I have to hear to say "I'll Pass.." for the time being. Please go to youtube and type in Ski-doo 600 e-tec. Except for a steady idle, no smoke, low emissions and easy on gas, she's ALL 2 stroke. The screamer you know and love.
Because I love the way all my current bikes run right now, just the way they are... What more could D.I. bring to a YZ250 that it doesn't already have? A smaller gas tank and a programmable power curve for starters

Would it produce better throttle response? Not likely, as the throttle response is already just short of telepathic. It absolutely would. The DI would fill in any and all gaps of the power curve. Even things you wouldn't feel seat-of-the-pants
Would it make the bike easier to start? Puh-Leeeeze..... Again, go to youtube. There's a clip of two ski-doo e-tecs that were in cold storage for 2 months. They start right up. immediately. Even a YZ250 would take a few kicks after sitting all winter.
Would it be any easier to maintain? I don't guess so... Fair enough, but this technology is about 90 years younger than the old. When roadracing changed to all 2 strokes in the 60's and 70's tuners complained about changing pistons and rings all the time.
Would it make the bike lighter? I don't know, is one of those systems really lighter than the carb that's already on there, you think? Subtract the weight of a gallon of gas and replacement it with some electronic components. I bet it's a wash.
One of the most enjoyable aspects of riding a motorcycle is the act of metering the fuel mixture flow into the engine. A carburetor is a fairly simple device that makes this a very immediate, in your face experience. The rider has un moderated control of his machine. He can make a mess of everything or that thing can sing motown down, it's all up to the guy pulling on the throttle cable. A throttle is a throttle. Direct injection only changes what happens when the rider gives the pistons some fuel to work with. The rider would still be 100% in control.

I just don't want to see another step in the direction of BORING, that's all. 2 strokes are the most exciting motorcycles to experience, by far, no doubt about it. Wallowing WAY behind that excitement is the rather bland and predictable experience of riding 4 stroke motorcycles. Yes, you still get down the track/trail/road on your mount, but they're not going to start rewriting the menu at Spark's any time soon, just because you can survive on baby food. Electric motorcycles aren't quite worth a mention in my opinion except maybe to demonstrate just exactly HOW boring and emasculated the experience of motorcycling can be made, for people who go to hell....    

When a significant addition to the complexity of a machine is made, the gains should be relative in value. If not they're not worth the added complexity in my opinion. I believe that in the case of the 4 stroke bikes, EFI was worth checking out because there were frustrating problems to be overcome with regard to the way the bikes ran. But even in that case, there have been losses to go along with the gains. They have engines with neater manners, but riders keep saying they lack the raw power of the carbureted bikes. When the hype settles, I'm not sure EFI is really exciting news unless you're a service department, or a guy who rides in Florida at the beginning of every week, then Pike's Peak at the end of every week. The systems are dependable but should there be a failure, are you going to fix it yourself? How were bikes of your machine's type working before EFI? Not very well? Then it's only right to go for it! If your bike was working EXTREMELY well with a carb, then there's a chance you'll end up as a fist prize sucker if you let someone replace a slide, needle, and a small assortment of ingeniously arranged orifices with a fuel injection system.  

My point is that if I was bummed out because 1/2 the time when I went to throttle my bike above idle, it flamed out like a carbureted 4 stroke does sometimes, or if it liked to occasionally stall in a corner and feel like it just dropped anchor as the rear wheel locked and dragged, maybe I'd be looking for an alternative fueling system... But, since I can't even remember the last time the fueling system on ANY 2 stroke has ever let me down, I'm just not looking. No thanks, I'll just keep my Mentos box of 70 cent brass jets and I'm fine.

REGARDING THE ENVIRONMENTAL EFFECTS...
I don't feel obligated to fret over the exhaust emissions of relatively tiny little dirt bikes, or any other bikes for that matter. Never have, never will. At displacements between 1/8 and 1/2 liter, I really don't think our bikes would be Mother Nature's biggest worry even if we each triple jumped a set of beached whales and landed on a rainforest telethon while carrying a sack of seal clubs, pipelines, and drilling rigs up north for hunting season. I've heard the chorus line of Kashi Gobblers, and Transworld KoolAid Kross California types singing about "Dirty", or "Smokey" 2 stroke engines, but I think we 2 stroke riders already do a lot to help our bikes run relatively clean.

Since our bikes use tuned exhaust and power valves (Except on those old Maicos and TS's) in conjunction with the intake to charge the cylinder from both upstream and downstream, some of the power band is quite efficient and unburned fuel loss is minimal. That's the part of the power band every rider seeks out and spends most of their time with, the sweet spot where the bike is most responsive. The inefficient part of the power band is the part that feels less responsive to the rider because the cylinder charge is less than ideal and riders can feel the lost potential, so we don't spend much time there.

Emissions tests can be run with all different types of test parameters, with a vast spectrum of results possible from the same engine. All engines have rpm ranges of peak efficiency for both power output and fuel usage/emissions. There are very large differences in efficiency, regarding both power output and fuel usage/emissions as a 2 stroke engine goes through it's rpm range, but that's a big part of why we love them. This also means you can test one and get either a very bad emissions sample, or a very good one, and all you have to do is change the rpm, engine load, or throttle position to get almost whatever result you're looking for.

I tune rich on purpose to keep engine temps down, my engines last for ever, and the smoke is just fine with me.

Thanks,

Jim

[reefmuncher]

Hey Chris I find your responses totally in sync with my thoughts there. Change is constant and two strokes of the 70's were very different than of the 90's. Powerbands became wider and smoother as designers worked on increasing rideability.

I'm impressed with those E-tec engines myself, my brother had an outboard with the setup. Fuel injection is pretty impressive stuff, my brothers bike (wreck) was sat up for well over a year outside in the weather. I wanted to borrow some parts off it and thought to kick it over. So I plugged up a battery and it seriously started and ran first time!! 

I think with the injection system being closed loop and sealed it prevents the lighter components of the fuel from evaporating.

Personally I don't have an issue with being nice to the environment if we can, I have friends who still choose to race with leaded fuel and I think that's pretty aweful really.

[Out of Order]

I was watching NASCAR Race Hub on speed last night, and they were talking about Nascar going to fuel injection. I thought they would keep the carbs for another century. If they go FI, I don't see the carb lasting too long because everything will be FI . But I believe the weekly series are keeping carbs for now.

[mxaniac]

We all want something different.  What I want is an updated 2-stroke with the latest suspension and frame geometry for today's tracks.  I want R&D money poured in to my bike, not BNG.  Yesteryears motocross bikes become obsolete.  If I must accept a new technology that complicates things then I must, that doesn't mean I prefer it only that it is the lesser of the two evils (complexity or obsolescence).

Hello Everyone,

I can only speak for myself here, but I don't want a direct injection 2 stroke UNLESS it's going to make something available to us that we don't already have.

If it means NEW RD350's, RZ350's, S2's, S3's, H1's, H2's, Suzuki GT's instead of GS's and things like that, then I'm probably into it, until I have the opportunity to buy one of the originals. If all we'd be getting out of it is more homogenized versions of what we have already, then forget it. I've heard that D.I. makes a 2 stroke run a little more like a 4 stoke... That's all I have to hear to say "I'll Pass.." for the time being.

Because I love the way all my current bikes run right now, just the way they are... What more could D.I. bring to a YZ250 that it doesn't already have?

Would it produce better throttle response? Not likely, as the throttle response is already just short of telepathic.

Would it make the bike easier to start? Puh-Leeeeze.....

Would it be any easier to maintain? I don't guess so...

Would it make the bike lighter? I don't know, is one of those systems really lighter than the carb that's already on there, you think?

One of the most enjoyable aspects of riding a motorcycle is the act of metering the fuel mixture flow into the engine. A carburetor is a fairly simple device that makes this a very immediate, in your face experience. The rider has un moderated control of his machine. He can make a mess of everything or that thing can sing motown down, it's all up to the guy pulling on the throttle cable.

I just don't want to see another step in the direction of BORING, that's all. 2 strokes are the most exciting motorcycles to experience, by far, no doubt about it. Wallowing WAY behind that excitement is the rather bland and predictable experience of riding 4 stroke motorcycles. Yes, you still get down the track/trail/road on your mount, but they're not going to start rewriting the menu at Spark's any time soon, just because you can survive on baby food. Electric motorcycles aren't quite worth a mention in my opinion except maybe to demonstrate just exactly HOW boring and emasculated the experience of motorcycling can be made, for people who go to hell....    

When a significant addition to the complexity of a machine is made, the gains should be relative in value. If not they're not worth the added complexity in my opinion. I believe that in the case of the 4 stroke bikes, EFI was worth checking out because there were frustrating problems to be overcome with regard to the way the bikes ran. But even in that case, there have been losses to go along with the gains. They have engines with neater manners, but riders keep saying they lack the raw power of the carbureted bikes. When the hype settles, I'm not sure EFI is really exciting news unless you're a service department, or a guy who rides in Florida at the beginning of every week, then Pike's Peak at the end of every week. The systems are dependable but should there be a failure, are you going to fix it yourself? How were bikes of your machine's type working before EFI? Not very well? Then it's only right to go for it! If your bike was working EXTREMELY well with a carb, then there's a chance you'll end up as a fist prize sucker if you let someone replace a slide, needle, and a small assortment of ingeniously arranged orifices with a fuel injection system.  

My point is that if I was bummed out because 1/2 the time when I went to throttle my bike above idle, it flamed out like a carbureted 4 stroke does sometimes, or if it liked to occasionally stall in a corner and feel like it just dropped anchor as the rear wheel locked and dragged, maybe I'd be looking for an alternative fueling system... But, since I can't even remember the last time the fueling system on ANY 2 stroke has ever let me down, I'm just not looking. No thanks, I'll just keep my Mentos box of 70 cent brass jets and I'm fine.

REGARDING THE ENVIRONMENTAL EFFECTS...
I don't feel obligated to fret over the exhaust emissions of relatively tiny little dirt bikes, or any other bikes for that matter. Never have, never will. At displacements between 1/8 and 1/2 liter, I really don't think our bikes would be Mother Nature's biggest worry even if we each triple jumped a set of beached whales and landed on a rainforest telethon while carrying a sack of seal clubs, pipelines, and drilling rigs up north for hunting season. I've heard the chorus line of Kashi Gobblers, and Transworld KoolAid Kross California types singing about "Dirty", or "Smokey" 2 stroke engines, but I think we 2 stroke riders already do a lot to help our bikes run relatively clean.

Since our bikes use tuned exhaust and power valves (Except on those old Maicos and TS's) in conjunction with the intake to charge the cylinder from both upstream and downstream, some of the power band is quite efficient and unburned fuel loss is minimal. That's the part of the power band every rider seeks out and spends most of their time with, the sweet spot where the bike is most responsive. The inefficient part of the power band is the part that feels less responsive to the rider because the cylinder charge is less than ideal and riders can feel the lost potential, so we don't spend much time there.

Emissions tests can be run with all different types of test parameters, with a vast spectrum of results possible from the same engine. All engines have rpm ranges of peak efficiency for both power output and fuel usage/emissions. There are very large differences in efficiency, regarding both power output and fuel usage/emissions as a 2 stroke engine goes through it's rpm range, but that's a big part of why we love them. This also means you can test one and get either a very bad emissions sample, or a very good one, and all you have to do is change the rpm, engine load, or throttle position to get almost whatever result you're looking for.

I tune rich on purpose to keep engine temps down, my engines last for ever, and the smoke is just fine with me.

Thanks,

Jim