My 2008 Yz 450f Review

[djtroy]

I have 06-07 jets in my 08 450f. They work fine for me. I went with a 48 / 170 with VP 4.2 race gas. I used my descretion on the jetting because nobody had concrete jetting that worked on the 08 yet and it had to be changed. Mine had all the symptoms of lean jetting. It seems ok now though. I am still waiting to see what others think about the jetting.

I ran the same jetting on my 06 450f also.

[endurodog]

Guys there is no year on the jets. The jetting can be year specific but they are Keihin jets in the Yamaha 4 strokes. YZ125 used Mikuni but that is different than what we are discussing, as well as several other models but not modern MX 4 strokes. From year to year the factorys can change the size of those jets but Yamaha is using Keihin carbs and they only take Keihin jets a 160 is a 160 no matter the year.

[IDAHOBALLER]

Hey anyone know if oil filter is same as 06. I was going to throw a scott in I called them hell they dont know. Is the paper one the same??????????

The filter are the same dimensions all the way back to the yz426f. The only differences between them is the filter material.

I have used yz426 oil filters in my 450's before since they are a brass screen type filter and can be cleaned and reused a few times before you get a new one.

I run a ready racing comp flow stainless oil filter now though.

[grayracer513]

Remeber this bike is factory is 160 main not 165 like 06 so 170 is a major change. DR D said 162 main, factory pilot, and 4th clip. 170 seems overboard

dj said he was using U4.2, remember? Just that change requires some jetting up on any bike.

Hey anyone know if oil filter is same as 06.

Yes, it is.

Guys there is no year on the jets. The jetting can be year specific but they are Keihin jets in the Yamaha 4 strokes.

Keihin carbs do sometimes change. Witness the type 20 & 21 pilots.

[endurodog]

Keihin carbs do sometimes change. Witness the type 20 & 21 pilots.

There are more changes than only that. Should we list them all??? Or should we state that they have not changed on the big 4 Modern 4 stroke bikes, because they have not.

[grayracer513]

Gray if you re read my post I said, "yes I realize you are running race fuel". According to Dubach 170 is overkill even with race fuel. 162 with pump gas, 165 0r Mayyybeeeeeeeeee 168 with race fuel. Only 168 if there is a serious elevation change.

It may well be too rich with a 170. People tend to do that, and 4-strokes tolerate it so well that they think they've done something good by it. I simply meant that the use of race fuel meant that it was not as far away from the recommendation as it might have otherwise seemed to be.

There are more changes than only that. Should we list them all??? Or should we state that they have not changed on the big 4 Modern 4 stroke bikes, because they have not.

The fact that they have ever changed makes the incorrect contention by the misguided parts "pro" that much more credible, or don't you agree?

[endurodog]

sounds like you to might have a history:naughty: . lets all play nice

Naa someone is more interested in an internet argument than helping the guys out. I'm done, he can confuse them all he wants.

[grayracer513]

sounds like you to might have a history:naughty: . lets all play nice

Don't know him. I guess he disagrees.

[todds924]

The part number has been changed on the oil filters. Same filter though, just a different number.

[smithjeb]

Rode my new 08 tonight, will post a more thorough review when I have time. Right now all I can say is it rocks...

[djtroy]

Remeber this bike is factory is 160 main not 165 like 06 so 170 is a major change. DR D said 162 main, factory pilot, and 4th clip. 170 seems overboard remeber this is not 06, they changed the motor causing jetting to be different. Yes i realize race gas is different but have you tried a 165 or 162 with stock pilot or bumped pilot up just one size, you went way up

I went up in increments but it didnt seem to really make a difference for me. I am also running a Yoshimura header and exhaust system. Its seemed to be ok with the 170 but its not like I would notice the difference between a 165 and a 170. It just ran like crap until it got richened up. I was just trying to get it to run better so I went up to a 170 main.

Did DR D tell you that a 170 was too much? Im sure he didnt say that. I was trying jetting on my own because like I said, no one knew what worked when I was doing this stuff a month ago.

But now that you guys have some jetting advice for me I will try different things.

[djtroy]

Holy Crapoli Batman! I put a quick turn throttle cam on my bike the night before a race and did a soft practice lap before the race to discover some outstanding pullon the uphill and straight aways. So first day of riding with the throttle cam... I pull up to the starting line on my cool new white black grey red with red anodized extras all over the YZ450 and this jerk kid standing next to the fence says, "Cool bike! Don't wreck!" So I'm doing my usaul clutch slip front brake loading in second gear waiting for the pin to disengage on my neighbors gate and shizaam it drops, I drop my clutch and twist while releasing the front break (I was waaaaay over the handle bars expecting some extra torque) got lazy and completely let my clutch go... low and behold, I'm gooning down the straight away with my chin practically touching the front fender to keep the front end down realizing I made a dreadful misjudgment on how much throttle I just hit the motor with... I flew off the bike and watched my bike head for the hole shot without me as my rearend bounces down the tarmac... That bike straight up takes off with a throttle cam. Any way, needless to say I got a crapy start the next time around because I was skidish about how much throttle to apply... but it made up for itself as I was able to stay on the throttle with very little effort after arm pump saturated my veins. Once I get used to that 1/4 turn throttle cam I'm confident I can roll to victory. First race on my 08 450... dead last 1st moto due to crash and 7th over all due to a lot of make up in the 2nd moto (and thats with being last through the hole 2nd moto).

I didnt notice this much of a difference on my bike as far as how the power felt. I did notice how much easier it was without having my elbow pointed to the ground when I was wide open. Its much easier to go wide open on uphill step up jumps now thats for sure. The G2 throttle tube I got was the pro version that takes out 10% of the turn. I have been thinking about getting the 20% cam for it.

[YZF831]

Ok, I'll add to the mix. I rode my 08 450 for the first time yesterday and I wasn't sure what to expect after reading all the mixed reviews about it. Let's just say nothing put a bigger smile on my face after the first ride. A little background, I am an "A" rider. About 50/50 between motocross and supercross tracks. I came off an 06 450 which I loved but this 08 is amazing. I could ride longer and harder without getting close to tired and armpump wasn't an issue for the first time in my life. I felt no issue with lack of bottom end. The power is sooo smooth off the bottom which was wonderful in the corners and then once you straightened out the mid to top would hit and it's "see ya later." Yes it was quiet and it "sounds" slow but don't for one second believe that. I was riding with modded Honda's, Zuk's, Kawi's, you name it and nothing had an edge over me. Most of them were my skill level and the ones that were faster than me, well let's just say I could last a whole lot longer than I used to so eventually the pass came on guys that normally keep a few bike lengths on me. Everyone wanted to ride it. It turns like a dream hands down, corners have never been more fun to me. Well that's my honest review so I hope I helped somebody out there. I love my 08 and I hope everyone else does too.

[djtroy]

And YES he did tell me that. But Im sure he isnt running yoshi stuff either. I am just saying that is high for any exhaust on this bike, Like gray said they tolerate it.

My buddy thought his was running lean on the VP u4.2 at 165 so he went to a 170 main also. Its hard to tell but to us it didnt feel right at 165 main. Who knows.

[aaronw]

For my level of riding, I raised my 07 Forks a hair above the 5mm line on the forks and it turns on a rail now... with the slight exception of tight 180 turns that require more body english to get it move the way it i want it to.

[torque_demon]

Un-fortunately, You can only win contingency money on bikes that are less than 2 years old. :confused:

[adamdf]

I didnt notice this much of a difference on my bike as far as how the power felt. I did notice how much easier it was without having my elbow pointed to the ground when I was wide open. Its much easier to go wide open on uphill step up jumps now thats for sure. The G2 throttle tube I got was the pro version that takes out 10% of the turn. I have been thinking about getting the 20% cam for it.

Isn't there a kit that comes with the different cams so you can switch for different tracks etc?

[torque_demon]

Yes

I bought the quicker turn 050 only. Works great

[djtroy]

Isn't there a kit that comes with the different cams so you can switch for different tracks etc?

Not for the "pro' setup

[CRFsean]

I know im late on this thread, but reading some other articles and I found off of yamaha's website all of the new mods.

Engine and tranny mods being

and this is straight from yamahas web site

-Revised intake port shapes, and revised intake and exhaust cam profiles increase combustion efficiency for improved torque and throttle response in the low- to mid-rpm range.

-Micron-level adjustment of piston external diameter minimizes piston-to-cylinder clearance for reduced vibration and mechanical noise.

-Adjustment of gear backlash between clutch primary gears and balancer gears achieves further mechanical noise reduction.

-A new, larger-diameter titanium exhaust header with revised taper characteristics enhances exhaust efficiency.

-First “punched cone” muffler ever on a production bike allows 35 percent length reduction and 270-gram weight reduction while meeting AMA noise regulations.

so im guessing that like everyone else is saying, a new exhaust, header, proper jetting and an acclerator pump cover will do the trick. you guys got me all scared cause I might be getting one very soon.