And the Banshee HAS low end grunt? The cvts on sleds do have a much wider range between "low" and "high" gears than a 6 speed gearbox, so they can get by with less low end. But it still takes alot of grunt to turn a 121 - 159" flat tire in a foot of powder. But it does seem to be a consensus here that the 400 powervalve can't make 90 horse on gas so I guess I'll just have to take it for what it's worth. Maybe it's just because it's not a Rotax[img]i/expressions/face-icon-small-happy.gif[/img]

 

95sport, I guess Beech kinda answered my statement. If you look at snowmo cylinders they are designed primarily for top end power. Dont forget that a lot of these motors are being engaged higher than your ATV would, some of them at 4000-5000. The cylinders are made to produce power. They have flat roof transfers (for more top end), lots of exhaust timing, and nice open transfer tunnels. Darrell at HPD designed his 416 after a snowmo cylinder. The powervalve helps widen the power, but your still engaging the clutch higher than a stocker so the need for power at a very low RPM is decreased. ATV cylinders generally have small ports for high velocity, angled transfer port roofs (some very steep),small transfer tunnels, and low exhaust timing. They have to fit a large variety of riders and have to keep wide power delivery. Snowmobiles, on the other hand, need the power output to get through deep snow and the tremendous loads caused by snow and the tracks they have to turn. The 250r Honda jug is about as open and good of a factory cylinder that was ever produced for an ATV. But take one of an XC600 jugs or something similar and compare them side by side. You'll see what I'm talking about. So when you buy good aftermarket cylinders for your ATV your getting that better technology and flow.Hope that helps some,Bubba

 

Bubba, that's a good explanation and I understand what you're saying. I guess my question goes my to my original post where I stated that I don't know anything about the Banshee motor. Given what the quad is built for, shouldn't that motor be much more like a sled motor than, say, the Poo 400 which DID have to fit a greater variety of tasks? Maybe I was just giving Yamaha too much credit with my assumptions![img]i/expressions/face-icon-small-happy.gif[/img] This then begs the question, If you're going to spend a ton of money to build the crap out of a motor just for sand drags or hill climbs, etc; why not start with a sled motor? Is it just because of the gearbox? I know there are some sled motor quads out there, but it doesn't seem like very many even compared to crotch rocket quads. Maybe I've just been on sleds for too long! For my money they are the most addictive motorized recreation there is. Just sucks that the season for riding them is so short.

 

From watching several of the bikes run with the sled motors, I would say the biggest thing is probably 60ft time. The sled motors, even clutched real aggressive, dont seem to have that real hard initial hit like the manual gearbox bikes do. IMO that seems to be where the times are different. Maybe only .1 or so, but that is tremendous when going fast already. Now as far as hill climbing or such, I cant see where I would prefer anything over an auto bike.

Back to the banshee motor being built like a sled motor............... Keep in mind that the Banshee motor is basically the old RD and RZ(liquid cooled version) design from way back in the 70's. They havent really been changed other than they dont use powervalves like the RZ bike did. The potential is there, but it does require some dollars to reach good power output.

By the way, I would love to have a nice modded (or even stock) 800 twin in an ATV chassis, even if it's just to say I have one[img]i/expressions/face-icon-small-happy.gif[/img]

 

Hell, I'd be happy with a 500. I'm a Doo guy in winter so I'm not 100% on the Poo's, but I think read that the 500 Liberty with VES is around 105hp stock. I'd settle for that[img]i/expressions/face-icon-small-happy.gif[/img]