So are these numbers at the crank?...or the rear wheel?

 

Being that it is a bike engine, it would mean that most likely its chain or belt drive right of the crank. Also in a motor cylcle aplication torque is not as important as hp. It takes allot of torque to turn two or in the case of 4x4, 4 heavy 25-26" tall tires. That motor mentioned would not compare to a Kawi v-twin that has about 45-50 crank hp and about 60-70lbs of torque. Now the quad has to have the torque but seldome needs that kind of Hp up on the top end, since most quads get very unstable at much over 65-70 mph. The mentioned motor would not likely make a very good quad motor unless it was used in a chain driven sport quad then it might be useable power but a 4x4 would likely suffer from lack of torque. All of my machines have been on a dyno and put out far more torque than HP. That said my 800's both are right at 49-51 hp at the wheels and the torque is in the 70s. My old prairie 650 is running 33hp at the wheels and 59 #s of torque. That said I would take the 59#s of torque at the wheels over 45#s and 75hp at the crank any day on a utility quad application.

 

What I have seen (internet) on the Bomb 800 is 62 HP and 52 lb-ft. torque. I have also seen (internet) is someone's lightly modified King Quad (DavAsh) getting about 32 HP & lb-ft torque. The Brute Force 750 was reportedly only 1-2 higher in each category on the same dyno as the KQ was tested on.

Yes, the machine would be sprot oriented, note the Raptor 700 Chassis [img]i/expressions/face-icon-small-wink.gif[/img]

Here is the source of my SV info

http://www.twobros.com/Cust_Service/...03_SO_Dyno.pdf

Anyway we are digressing to much--back to the topic--I hope the new Grizz is a sub 800cc EFI motor. Maybe they can combine the Vtwin of the Bomb & Brute with the DOHC of the KQ and really have something? Maybe a revised Raptor 700 EFI?

 

A few thoughts to ponder:

You can't just look at the peak numbers, but WHERE they make those numbers. The 750 and 800 ATV engines are making low- to mid-50s in torque at the crank (650s are in the low- to mid-40s).... and they make it in the 4000-5000rpm range with thick torque curves in the lower rpm range (as do most utility ATVs of all engine classes). The SV 650 engine you're talking about probably makes peak torque closer to the 6 or 7k rpm range (since it comes from a "bike"), and has a much weaker torque curve in the range that ATVs make peak torque. And the ATV engines are generally designed to make peak horse power at or below 7k rpm, where as street bikes make peak hp well over 8, sometimes 10,000 rpm. Two completely different purposes are sought after here. You can't build a naturally aspirated engine with a flat torque curve, you must give up in one area of the powerband to gain in another, and vary the rpm ranges accordingly.

Just looking at the spread in the peak values for hp and torque in an engine can tell you a lot (without looking at the rpm the peaks occur). Generally, engines that make much more hp than torque are high-rpm runners, with little to show as far as low rpm torque. Engines that have peak hp and torque at close to the same value are often more low-rpm oriented. For mudding and pulling, you want as much torque as possible at as low of rpm as possible.

45 lb-ft of torque at 3500rpm makes 30hp. 45 lb-ft of torque at 8000rpm makes 68hp. 45 lb-ft of torque at 12,000 rpm makes 102hp. And you wonder why most street bikes turn over 12,000 rpm to make 150hp+ (and are complete dogs when you punch the throttle at 3k rpm... i have a CBR 600 and know this from experience). A street bike oriented engine in a heavy utility ATV is a dissappointment waiting to happen. My CBR 600 doesn't even wake up until the tach hits 5k rpm (and there's almost ZERO thrust under that rpm), starts kicking hard at 6k rpm, then you better hang on for dear life while the tach screams past 10k rpm. An ATV engine feels completely different.

 

99MudKing thats the best reply I have ever seen on the big "Why cant we have huge HP in our quads" question. [img]i/expressions/face-icon-small-happy.gif[/img]
Very nice.......thanks.

 

I am actually surprised Yamaha didn't introduce a bigger Griz this model year. I have a feeling they will have something all new for '07 though. Personally, I hope they go with a side by side twin, efi, and have it tuned for sportiness.

 

I had herd a rumor a while back that the name on the new machine might change and the gizz continue in its current form. I also herd from the same guy that the new yamaha motor was in fact a parallel twin similar to the Polaris. I am personaly partial to the v-design do to its lower CG and the V twins I have seem smother and more balanced than the parellel twin I had in my Polaris 800. That may have been do to the fire sequence the polaris had, both cylinders moved up and down together but fired seperate. I still do not understand the Logic behind the polaris design, with both cylinders moving togeth that puts out more vibration than a V design where the motion of one is countered by the motion of the other. The Polaris do not seem to have the benifit of the counter balance of the other cylinder.

 

Yeah, but a side by can be a lighter, more compact design that has the potential to rev out a bit better. Inline 6es tend to be smoother than v8's in a car, I wonder if an Inline 2 cylinder could be smoothed out as well?

 

a forward inclined parallel with downdraft bodies could be made to have a similar CG as a twin, and take up less space (easier to service)

Their TDM900 is fuel injected parallel with 86HP.

 

If you're designing from scratch, V vs parallel is comletely separate from CG. Actually parallel design allows for more displacement in a smaller phisical package, allowing for a lower center of gravity.

Don't make an assuption about a bike that hasn't even come out yet based on some other, older bike.