Dirt bike engine vs quad......why the differences???
#1
02-11-2005, 03:39 AM
Dirt bike vs quad......why the difference???
If you look at dynos of the CRF450 dirt bike vs the Yamaha 450 dirt bike, the Honda has more power almost everywhere in the curve. And more important, the Honda keeps making its power at a higher RPM than the Yamaha does . But with the quads, why is it the opposite? The Honda TRX power checks out early, while the Yamaha is still making power at a higher RPM. (But the Honda does have the edge on the low end.)
So why the big difference between the TRX and CRF engines. I know that the stroke and bore are different, as are most all the engine parts. Did Honda tune specifically for more low end grunt, then have to balance this out with tall gearing to keep the top end (and keep it from being wheelie happy)? Or did Honda just tame the beast down for liability reasons?
What are your opinions?
So why the big difference between the TRX and CRF engines. I know that the stroke and bore are different, as are most all the engine parts. Did Honda tune specifically for more low end grunt, then have to balance this out with tall gearing to keep the top end (and keep it from being wheelie happy)? Or did Honda just tame the beast down for liability reasons?
What are your opinions?
#2
02-11-2005, 09:27 AM
#3
02-11-2005, 10:38 AM
Dirt bike engine vs quad......why the differences???
I pretty sure it is because when someone buys a crf450, more than likely it is for track use. So they want a more high tuned engine in that for racing performance. And in the TRX, most of the sales are going to recreational type riders so they want something a little more managable, and reliable. Look at the piston skirts for example.
I know if I was going to be given 1 quad and 1 dirtbike right now , I would choose these two for those reasons. I want a bike to race, and a quad I can have fun with, and yet still fast enough to race. That is if I could keep the Z too, that is the best all around quad right now IMO.
I know if I was going to be given 1 quad and 1 dirtbike right now , I would choose these two for those reasons. I want a bike to race, and a quad I can have fun with, and yet still fast enough to race. That is if I could keep the Z too, that is the best all around quad right now IMO.
#5
02-11-2005, 11:11 AM
Dirt bike engine vs quad......why the differences???
Bikes aren't under constant scrutiny by the EPA so they have less restrictions ( if any ) then a quad so their motors are more performance tuned from the factory. You can buy a bike designed for closed course competition only and put a sparky on it and ride wherever, you can't buy a quad without a sparky period. Bikes also aren't limited in speed, noise or emissions but quads are, that's why they respond so well to just bolt on mods. These are just my opinions and observations...........
#7
02-11-2005, 12:17 PM
Dirt bike engine vs quad......why the differences???
I think the smaller bore and longer stroke in the quad motor have a lot to do with it...... Possibly? The stock cam is very mellow compared to the HRC cam. The lower compression and combustion chamber configuration is also different than the bike motor. This is a good topic.
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#8
02-11-2005, 12:31 PM
Dirt bike engine vs quad......why the differences???
Originally posted by: LTZevil400
Bikes aren't under constant scrutiny by the EPA so they have less restrictions ( if any ) then a quad so their motors are more performance tuned from the factory. You can buy a bike designed for closed course competition only and put a sparky on it and ride wherever, you can't buy a quad without a sparky period. Bikes also aren't limited in speed, noise or emissions but quads are, that's why they respond so well to just bolt on mods. These are just my opinions and observations...........
Bikes aren't under constant scrutiny by the EPA so they have less restrictions ( if any ) then a quad so their motors are more performance tuned from the factory. You can buy a bike designed for closed course competition only and put a sparky on it and ride wherever, you can't buy a quad without a sparky period. Bikes also aren't limited in speed, noise or emissions but quads are, that's why they respond so well to just bolt on mods. These are just my opinions and observations...........
#9
02-11-2005, 01:56 PM
Dirt bike engine vs quad......why the differences???
From what Ive seen, the biggest difference is the cam shaft. Its a different profile and pattern on the quad. The cam shaft is the biggest control over how a motor behaves, whether its torquey down low, or whether it can rev and build hp.
#10
02-11-2005, 11:54 PM