My 2008 Yz 450f Review


340 replies to this topic
  • adamdf

Posted September 28, 2007 - 05:16 AM


So i wonder if MXA got a test unit for their review? Or did they just test an 07 exhaust? Hmm, i'm thinking if they tested an 07 exhaust that there is probably even better results to come when the 08 exhaust is released (maybe not much better, but a little).

  • matts06yzf

Posted September 28, 2007 - 07:06 AM


By the way, anyone els gonna run the Dr D on the 08, here was the base line they gave me. Sea level.
162 Main Move the needle clip to the #4 Stock pilot


I called yamaha of troy they said 06-07 jets will not fit 08. I dont see this being the case but I am on hold now with Yamaha customer realations. I will find out shortly:rant:

  • matts06yzf

Posted September 28, 2007 - 07:16 AM


Ok Yamaha of Troy says Nope wont work. Called yamaha they said they didnt know, so they sent me to a "product specialist" :thumbsup:. Guess what? He had no idea either. So Finally he said 'they think' it will work. Stock jetting is 160/45

  • rickallen124

Posted September 28, 2007 - 07:51 AM


Why wouldn't the jets work? It's the same carb isn't it? I never saw anything where yamaha said they changed the carb from the 07-08. They changed the jetting and that's it.

  • Bigcr

Posted September 28, 2007 - 08:25 AM


The guy from YOT is on crack. Of course the jets will work.

  • adamdf

Posted September 28, 2007 - 09:37 AM


The guy from YOT is on crack. Of course the jets will work.


That's what i was thinking. IS there any reason why they shouldn't fit? Matt you should have asked the YOT guy why he thought so, i'm pretty sure his response would have been "ammmmmmm, i'll get back to you on that one".

  • grayracer513

Posted September 28, 2007 - 10:09 AM


That's what i was thinking. IS there any reason why they shouldn't fit?

You have to think like a parts man who has no technical background (there are way too many of these.

If the 160 in an '08 has a different part number than the 165 in an '07, then the '07 jet is the wrong part, see?

  • matts06yzf

Posted September 28, 2007 - 10:52 AM


That's what i was thinking. IS there any reason why they shouldn't fit? Matt you should have asked the YOT guy why he thought so, i'm pretty sure his response would have been "ammmmmmm, i'll get back to you on that one".


I just hung up not worth my time ya know:bonk:

  • djtroy

Posted September 28, 2007 - 11:22 AM


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.

  • matts06yzf

Posted September 28, 2007 - 12:20 PM


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.


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

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  • matts06yzf

Posted September 28, 2007 - 12:33 PM


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??????????

  • endurodog

Posted September 28, 2007 - 02:08 PM


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

Posted September 28, 2007 - 03:06 PM


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

Posted September 28, 2007 - 03:08 PM


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.

  • matts06yzf

Posted September 28, 2007 - 03:13 PM


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.

  • endurodog

Posted September 28, 2007 - 03:26 PM


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

Posted September 28, 2007 - 03:33 PM


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?

  • matts06yzf

Posted September 28, 2007 - 03:45 PM


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

  • endurodog

Posted September 28, 2007 - 03:47 PM


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

Posted September 28, 2007 - 03:57 PM


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

Don't know him. I guess he disagrees. :confused:





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