...................The fact is, is yamaha did de-tune the yfz because of all the restrictions there are on atv's. YOu'll find hardly any on the dirtbike version, because all the law suites are against quads

#1 On the yfz, you'll find an extremely corked up, heavy exhaust system. The dirtbike happend to come stock with one of the best (all around broad power) exhaust pipes made.
#2 While I agree that it has to come with a lid, it does not need to have such a restrictive intake on it. The intake is really bottle necked down, and there is a lot of unneccesary crap in there ie, the screen and cone contraption.
#3 The yfz is indeed jetted way way to lean, and while you may be right, about it burning cleaner, also takes away from power, and iff ridden very hard or long with stock jetting, could end up giving you problems.
#4 The yfz came with the wr timing to de-tune it some more. There is a lot more topend power and speed to be had with the yz timing.

So, this is the question I have for you. Yamaha already had a race proven motor from there yz. They knew what made the best power, so why do you think they put in a bunch of extra effort to hurt performance on the atv? Why not give it the better exhaust? Why not give it an intake like the yz? Why not jet it properly like the yz (with the correct jet size and correct "ncvq" stock yz needle? Why give it the trail bike "wr" cam timing? .............They obviously knew what was the best combination and the fastest stock setup, cause they ripped the motor out of the dirtbike. Why on earth would they de-tune the race quad version you ask??????? ANYBODY CAN GET ON A QUAD AND GO GET THEM SELF HURT OR KILLED. Dirtbikes on the other hand, you have to have a little knowledge on how to operate it, to even get up to a speed of getting hurt. Look at all the age requirments and rules for atv's. THEY DE-TUNED IT CAUSE IT WAS TOO FAST FROM THE FACTORY IN ATV FORM. There are not nearly the lot suites on dirtbikes, as there are on atvs. They can get aways with having raw power on the yf450f, but they knew they couldnt on the atv, cause they knew they would get in trouble!

 

thank you. atleast someone here knows what they are talking about.

 

hey 135boom I noticed in your sig it says you have a yz450f exhaust cam in yours how much did that help? also i have another question for you guys/gals... what would be a good exhaust system to go with? I saw a lte dual exhaust system which I liked just because its different and it said to have dyno'd 12 peak hp. but I figure a dual exhaust would be pretty heavy with two mufflers. im really just looking for a exhaust system that performs good bottom end and wont break the bank. can yall help me out on this too?

 

Well said man, I agree completly! [img]i/expressions/face-icon-small-smile.gif[/img]

 

Part of the reason for the bike being so cluttered with its intake and exhuast components is because less air passing through the engine means you dont need as much gas. If you decrease your need for gas, you can drop the jetting. If you drop the jetting enough, you are green sticker legal.

 

DR. D (dubach racing development) made a pretty good muffler. it's not extremely loud and gives u some hp! also, it's not that expensive. JMO

 

Boy you guys sure get your panties in a wad! Okay I'm calling Yamaha right now and telling them to put a louder pipe on it and no air lid and rich jetting so maybe they can't sell them in California. [img]i/expressions/face-icon-small-shocked.gif[/img]

You guys sure about the lawsuit thing? I thought that all died back in the 80's, and it doesn't add up when you can buy a street bike that runs 10's off the showroom floor that they'd be worried about an extra 10 HP in their little quad.

 

Well..............yeah. Did you happen to notice allthe age requirments on atvs and how atvs do get detuned. YES, your right, you can buy street bikes off the showroom floor that can run low 10's, and there is not one requirment about buying one either. YOu could have zero riding experience, go in a buy a r-1, and kill yourself the same day. Same with the yz450f. But quads have given companies problems, and thats why there so stringent on rules and such with the quads. Thats the way it is. Thats why yamaha had to detuine the yfz so badly. There lawyers would have never let them have yz450f power on 4 tires, it would have been asking for a lawsuit.

 

YOu want another example. Look at the raptor. 660cc, that makes 34-35 horsepower. Welllll, in the old street bike form of that motor, it made like 65-68 horsepower. THey cut the nuts off of quads so that they cant get introuble. more than half the people that buy raptors and yfz's would be crashing them all the time, and all disfigured by now, if they had all the power they should come with. Look at all the stuopid warning labels all over your quad. Now look on the street bikes, dirbikes, and snowmobiles. YOu will find NO waring labels riveted onto there sidepanels!

 

Sorry, I have not updated my sig fro quit some time, I usually never come here anymore, as there is a lot of useful info on "other" yfz cites, that leave out all the childish bickering and such.
As for the yz cam, you can only run one if you have a kickstarter. It will not work with elec start. You'll end up like I did, having to turn your quad over 100 times before it will start. The reason I had gone with it, is its the same power increase up top as the cammod, but it keeps the decomp pin in the correct place. Problem is, is the decomp pin is too long on the yz cam. The yfz decomp pin is like 1.00 to 1.05 long, and the yz450f decomp pin is like 1.60-1.65 long. Thats what causes hard starting. DONT DO IT WITH ELEC START.
So, what I had done, is put the stiock cam back in and do the cammod. Same power as the yz cam gave me, but with normal easy starting.
I am now running a pair of webb race cams. THere fricken insane! As far as hotcams go, they too are a good choice for someone on a budget and too add some power. They are a mid-high power increase. THe webb race profile has more lowend then the hotcams, and a lot more mid and high. Webb also makes a torque profile, but from what I have heard, the race offers the smae amount of torque, with the added benefit of more mid and top.
As far as an exhaust goes, well, theres a ton of them out there. I would never go with a dual system, as part of the reason you want an after market exhaust is to reduce weight on the quad. That stock can is fricken heavy. I personally went with the full procircuit Titanium -4. I love its power, it added power all over the entire range, with a much bigger hit in the mid and topend. I know a lot of folks have been really happy with hmf too. My Ti-4 only weights like 4.5 LBS!!!!!! I cut more then 10 lbs off the stock exhaust system!!
Anyways, hope that helps. When you do your exhasut make sure to jet it properly, as the yfz come form the factory really lean as it is. And I would look into doingna intake when you do your exhasut as well. You'll be rather inpressed with the results.
I have had a warrior, then a banshee, then a raptor, now a yfz, and have never been so thrilled with the difference that aftermarket exhaust/intake/jetting has made.