to answer the original question, no.
it wont be as fast... weight is a factor in drags... but not that much. the 450 being a very fast and high revving engine gives it the acceleration that a slower revving engine doesnt have.

 

Actually, higher revs typically have higher top end hp, and less torque. Less torque means less accelleration. The yfz is quicker off the line though.

 

i was just cheking out the dyno graphs on fmfracing and the yzf450 is REAL corked up compared to the yz450. the quad is puttin out rite around 33 stock and the dirt bike is up around 43. even with an exhaust the yfz doesnt come close to the dirt bikes HP. the stock yfz is actually putting out around the same numbers as the yz250f. look for yourself.

what is it that is making the yzf have such lower numbers?

 

i know you all hate dirt wheels quotes, but when it reviewed the raptor...it said in stock form with gearing changes, the raptor would do 95 mph....seems logical to me and that is pretty darn fast in stock form with gearing changes.

everyone says the raptor motor is clogged up in stock form(add pipe and remove lid)...well maybe its geared wrong too(more for woods/mud/sand/trails) less for mx/racing[img]i/expressions/face-icon-small-smile.gif[/img]

anyway...the 450 is definately designed for what the raptor isnt...so enuf about comparing the two...cause they are apples and oranges

 

so what if it weighs the same and has an aftermarket rev limiter, hitting say 11'000? stock its 9'000 if its even possible to go up that much without doing damage

 

Which dirtwheels said this? I have all of them here and I don't have one dyno of a STOCK YFZ making 45 HP. The only dyno in the magazines that say 45 is the one where they put the full GYT-R exhaust on the bike. If I'm wrong let me know where I can see this.

 

it would be a rocket i think...

 

Installing a CDI with a higher RPM limit will NOTY give you more speed.

in 5th gear the bike will not go much faster than HP peak RPM. Meaning most YFZ's making max HP at around 9500 RPM will very seldom go past 10 000 RPM in 5th gear. Wind resistance will limit the top speed, due to bike making less and less HP with each RPM over the max.

You can have a CDI limiting it at 30 000 RPM if you like, the bike will not go faster than the stock CDI equipped bike.

Add a pipe and do some airbox changes and the raptor can stick with the 450. On paved road I have raced lots of different YFZ 450's and the raptor can stick with them.

The problem is that the raptor makes to much torque that it wheel spins or wheelies of the line. The 450 launches way better since it can keep traction much better.

Next time you race a YFZ 450 try doing it on a paved road and do a rolling start with both bikes in 2nd gear. The raptor sticks right next to the YFZ and kills it in 5th.

Now for some dyno numbers.

I have dyno tuned a couple of YFZ's DS's and raptors.

Friends YFZ 450 with GYT-R slip-on. No lid, Pro Flow adaptor and air cleaner with Dynojet kit dyno tuned at 46HP with stock tires.

My raptor with sparks pipe, Dynojet kit, L&A adaptor and K&N dynode at 49.5 HP with stock tires.

Stock raptors makes about 36HP and Stock 450’s make about 38HP on the same dyno.

The YFZ wins races because it launches better. Gear for gear the raptor does about the same speed as the YFZ. The YFZ rev much higher but uses a smaller gear ratio, due to its limit torque. Raptor rev lower but uses a taller gear ratio, thanks to its higher torque. We change at about the exact same time in every gear.

 

i think the only reason a lot of the races are so close w/ the yfz is because it revs so fast that traction is HUGE issue for the first 30 feet. (even starting out in 2nd gear.)

I've got the full GYT kit, and seeing how it performs, I'd definately have to say it was pushing 43-45HP... I'm just WAY too lazy to go get it dyno'd. If I hear that thing running, I wanna be on it... not watching it.

I put 12 hr on it this weekend (Sat & Sun) and even w/ gloves on I got a nice big blister on my throttle thumb... [img]i/expressions/face-icon-small-smile.gif[/img]

 

Raptors redline at 9000 not 7k. Light mods to a rappy will bet a 450 with the same weight rider.