2 Strokes... Will They Be Back?

[DJ99X]

It wouldnt be like riding an electric bike. They have one gear, where the power varies over the rev range. With CVT's, the revs stay the same (so same power), but the gear ratio changes. Check this out (guage in MPH):



See how the revs stay at ~6K RPM whilst the velocity increases

[JETZcorp]

I would never buy a bike with a CVT. I don't care how fast it is. A huge part of what makes a bike fun is the need to work the transmission with clutch, shift, and throttle. It'd be even more boring than an automatic, and the sound of a constant-RPM would just feel wrong. I can see how it would make a bike extremely fast, but it would be the equivalent of taking a .357 Magnum to the face of a kitten. The soul would be gone.

[cpt_Slow]

It wouldnt be like riding an electric bike. They have one gear, where the power varies over the rev range. With CVT's, the revs stay the same (so same power), but the gear ratio changes.

I understand how the CVT works, I'm pretty sure an ideal electric bike should put out consistent torque figures throughout the rpm range (hence the lack of gears).

[jlv]

Wow, I'd love to have a go at such a bike. In saying that, it would probably be boring, sorta like an automatic car.

Four stroke, automatic, same difference...

I can see how it would lose some fun factor. But if you wanted to make the ultimate lightweight, powerful yet easy to ride MX weapon a two stroke CVT would be hard to beat.

[JETZcorp]

It would lose a LOT of fun factor. It'd be like going from MXS as we all play it now, to MXS in arcade mode. Sure, you'll probably go faster, but the reward of conquering a challenge isn't there. I don't think the CVT would sell well with recreational riders for this reason.

[DJ99X]

Arcade mode is slow as

[jlv]

It would lose a LOT of fun factor. It'd be like going from MXS as we all play it now, to MXS in arcade mode. Sure, you'll probably go faster, but the reward of conquering a challenge isn't there. I don't think the CVT would sell well with recreational riders for this reason.

No, it would be more like playing with auto clutch RPM set to 12,000. I admit that I do like the challenge of keeping a 125 singing and I would miss that. New technology always brings new challenges though.

[chez]

this guy is keeping 2 strokes alive.
http://www.youtube.com/watch?v=jzrgIhHgNsA

[rideblue56]

i must say that was a pretty awesome video. dude can ride

[DJ99X]

It would lose a LOT of fun factor. It'd be like going from MXS as we all play it now, to MXS in arcade mode. Sure, you'll probably go faster, but the reward of conquering a challenge isn't there. I don't think the CVT would sell well with recreational riders for this reason.

This is what we would need then. The ability to choose manual gearing, whilst using the CVT setup. It would be pretty simple you would imagine. Just make it have 5 different positions instead of infinitely many. You would think that you would be able to map your own gear settings, as well as the amount of gears you have

[NIKK SPILLANE #244]

this video is pretty sweet, ktm 250
http://www.youtube.com/watch?v=iBSBd0UWfnk

[cpt_Slow]

It would lose a LOT of fun factor. It'd be like going from MXS as we all play it now, to MXS in arcade mode. Sure, you'll probably go faster, but the reward of conquering a challenge isn't there. I don't think the CVT would sell well with recreational riders for this reason.

This is what we would need then. The ability to choose manual gearing, whilst using the CVT setup. It would be pretty simple you would imagine. Just make it have 5 different positions instead of infinitely many. You would think that you would be able to map your own gear settings, as well as the amount of gears you have

It looks like that simply switches between fully manual and CV, I think what you are trying to say is something that say was constantly variable between 0-10mph as in 1st, at which point the CVT is at its limit so you notch it up to second and again it constantly varies to stay at 12000 rpm until 30mph when it reaches its limit again. Basically a limited range CVT connected to your average gearbox. I'm pretty sure this would detract to from the "lightweight" aspect and probably sap more power too. But hey, this is mostly dreaming so who cares....


Back on topic (was it off? Not really.) I would say those tests with pro riders were probably a little unfair due to the riders. They have been racing four-strokes mostly, probably since they were on 80s for the younger guys, so they were used to the characteristics, would take some time to get back into the two-stroke swing. A pro should be able to make the most of the huge peak power figures, smooth power curves should be left for the amateurs who can't keep it on tap.

[JETZcorp]

I actually really like that "manual gear simulator" option for the CVT, I hadn't thought of that. Although I'm still a little skittish about the CVT on an emotional level (look at it, how can it POSSIBLY work?) but intellectually I like it now. Although, if you're going to go all CVT and have a constant-RPM powerplant, you might as well stop beating around the bush and just put a jet turbine in the bike. Chrysler made a turbine car back in the days of yore, and while it only made 130 horses, those 130 horses came with 425lb-ft of torque. Turbines aren't so great at normal engine operations (they take a long time to go from idle to full output) but love constant-revs. I don't want to get too off-topic with all this jet engine gibberish, but I do think it would make an interesting project.

[Xxslayer410xX]

I don't know if they'll come back, but I know there a dam sight easier to start than my crf!

mmmm well the 125s and 250s are but like the big bore 2 strokes like the 500s are def a lot hard to start haha

[jlv]

I actually really like that "manual gear simulator" option for the CVT, I hadn't thought of that. Although I'm still a little skittish about the CVT on an emotional level (look at it, how can it POSSIBLY work?) but intellectually I like it now. Although, if you're going to go all CVT and have a constant-RPM powerplant, you might as well stop beating around the bush and just put a jet turbine in the bike. Chrysler made a turbine car back in the days of yore, and while it only made 130 horses, those 130 horses came with 425lb-ft of torque. Turbines aren't so great at normal engine operations (they take a long time to go from idle to full output) but love constant-revs. I don't want to get too off-topic with all this jet engine gibberish, but I do think it would make an interesting project.

Definitely agree. One of those little RC turbines on a CVT bike would be awesome. Wouldn't surprise me to see a full size 40 hp bike under 150 lbs if you went that way.