2007 WR450 Performance Mods

If you have an 06 AIS kit the plug for the exhaust port wont fit. You will have to fabricate a plate or wait for an 07 kit.

plug.jpg

i had a 06/07 kit and the plug didn't fit, I need a piece of metal like this. For a quick fix, I left the tube on and put the aluminum cap over it, using a bit of the hose inside to seal it. that soft metal insert would not have fit.

This looks much better, will have to get on that :thumbsup:

OK, just purchased my new WR450F 2008, which will be my third generation 4T Yamaha. On the first two, a (2001) WR426F and (2004) WR450F I did all the free mods using this forum. The 426, as it had no auto-decompressor, could be simply put into YZ mode by simply advancing the exhaust cam-shaft 1-tooth. On the 2004 I purchased an OEM YZ cam and relaced the original. I always noticed more power (also bottom) and a much snappier bike responsive revving bike that was also easier to start. Now many years later I am reading this forum again and almost see no one talking about this anymore. Is the 2007 and later version so different that this mod is almost not beneficial. Please advice.

OK, just purchased my new WR450F 2008, which will be my third generation 4T Yamaha. On the first two, a (2001) WR426F and (2004) WR450F I did all the free mods using this forum. The 426, as it had no auto-decompressor, could be simply put into YZ mode by simply advancing the exhaust cam-shaft 1-tooth. On the 2004 I purchased an OEM YZ cam and relaced the original. I always noticed more power (also bottom) and a much snappier bike responsive revving bike that was also easier to start. Now many years later I am reading this forum again and almost see no one talking about this anymore. Is the 2007 and later version so different that this mod is almost not beneficial. Please advice.

Yes, a cam swap in the 07' - 08's is a valid mod with noticeable power gains. Just do a search for "cam shafts 07" in this forum... you'll find books written on cam swaps... I wrote a few chapters my self. My $.02 is to go with a Hotcam specifically made for WR instead of OEM YZF cams, you'll have better luck with the e-start working afterward...... you'll hear other opinions but read up and make a decision on your own... If you decide on OEM cams, PM me... I have set I'll let go real cheap:busted:

Here you go...

scan0001-1.jpg

what year/model is this publication referring to? I received an "extra" jet in my kit it is a #110 and am I to assume I can just spin it into the tapped "empty" hole in the carb throat beside that "#70 pilot air jet? What circuit is this affecting? and what might this do to my current jetting?

My bike has most of the free mods done except for the gray wire and I still get a stall occasionally when burping over a big westcoast log.

I'm reading a ton of good info here and it helps, keep up the good work everyone!

Andy

I've read a lot about the grey wire, but can someone tell me where the TPS is? My 07 has a bad surging problem! Thanks

I've read a lot about the grey wire, but can someone tell me where the TPS is? My 07 has a bad surging problem! Thanks

its the on the left side of the bike coming out of the carb (should be a white plug)

Just completed the mods on my 08 wr450. Air box, pipe insert removed, throttle stop. Waitng on AIS Kit. One issue not sure if its a problem. When I cut the throttle stop to the specified 18.2mm I must have cut on the wrong side of my line. When I checked it, it ended up at 17.32. Is this a big issue. Should I get the new screw? I installed it and all seems well when I roll the throttle. Havent riden yet due to work and weather.

Just completed the mods on my 08 wr450. Air box, pipe insert removed, throttle stop. Waitng on AIS Kit. One issue not sure if its a problem. When I cut the throttle stop to the specified 18.2mm I must have cut on the wrong side of my line. When I checked it, it ended up at 17.32. Is this a big issue. Should I get the new screw? I installed it and all seems well when I roll the throttle. Havent riden yet due to work and weather.

What AIS kit did you buy? If its the GYTR it will have a yz throttle stop screw

jjkile....that must have been a WIDE line.

I have heard reports of the throttle sticking "wide open" if the stop is to short. Since a YZ stop is cheap, I would just put one of them in and have peace of mind knowing it is right.

Just completed the mods on my 08 wr450. Air box, pipe insert removed, throttle stop. Waitng on AIS Kit. One issue not sure if its a problem. When I cut the throttle stop to the specified 18.2mm I must have cut on the wrong side of my line. When I checked it, it ended up at 17.32. Is this a big issue. Should I get the new screw? I installed it and all seems well when I roll the throttle. Havent riden yet due to work and weather.

You also risk hammering the slide because you are using the inside of the carburetor as the stop instead of the screw.

I ordered the tt kit, so no screw. Yeah, I dont know how I missed the mark so bad. I even used a digital caliper, but I think I forgot to zero it out before I marked the screw. The last thing I want is the throttle sticking on this thing. Thanks for the input guys.

I guess I better get the part number. The chick at the closest dealer just tried to tell me the screw was 57 dollars. LOL Sometimes I wonder.....

Just get a WR throttle stop from someone else who was too lazy to just cut it to size. I am however wondering where your 18.5 measurment came from? I'm guessing it doesn't include the screw head. Try this pic from Markturbo

100_1003-1.jpg

WR Dave.

I got the 18.2 from somewhere on this forum. But the measurement said from the shoulder to the tip. So it didn't include the head the way I understood it. I'm not sure which post, but I did read almost all the forum before I started. I didn't check the measurement from the top to the tip, to see what the overall is.

Hi I've just upgraded from a WR426 to an 08 WR450 and tbh I was abit disappointed with the lack of power in comparison. So I have been goin over the bike to do all of the free mods but have found they have all already been done. However there is no throttle stop in the carb at all but I still only have a quarter throttle? is it ment to increase to a 180 twist or is it just a case of the slide opens abit more with the yzf screw??

I am going to order a yzf screw but am just wondering about the half throttle thing??

thanks

I am liking of the posts, very instructive. but nowhere I can read someone about the hoses of the carburator, I know exists 2 hoses if I leave like stock it sucks water and stops the bike.

someone knows exact hoses to change of place ?

I am liking of the posts, very instructive. but nowhere I can read someone about the hoses of the carburator, I know exists 2 hoses if I leave like stock it sucks water and stops the bike.

someone knows exact hoses to change of place ?

Yes, the hoses that come out of the top/sides of the carb.

what year/model is this publication referring to? I received an "extra" jet in my kit it is a #110 and am I to assume I can just spin it into the tapped "empty" hole in the carb throat beside that "#70 pilot air jet? What circuit is this affecting? and what might this do to my current jetting?

My bike has most of the free mods done except for the gray wire and I still get a stall occasionally when burping over a big westcoast log.

I'm reading a ton of good info here and it helps, keep up the good work everyone!

Andy

 

 

I"VE GOT A HUGE PROBLEM. 

 

I accidentally removed the factory installed air jet shown in figure 4, and installed the mail air jet in it's place. Now I cannot remove it. It spins freely but does not back out. Please help me, it was late and I F'ed up royally I know. Anyone have any idea how I can remove it, or will it effect the bikes performance? I was in the process of installing the AIS kit from GYTR on a 2009 WR 450F

I'm seeing some mixed information concerning doing the Exhaust Cam Mod on a 2007 WR450F. First can it be done, and if so does it work the same as on a WR250F where you rotate the cam forward one tooth and grind the decompression pin 1MM?

 

Thanks 42A

I hope this is the right section: I just bought a 2007 WR450 and I'll be doing AIS, intake mod just as soon as I get the parts. However, my question is what is the stock main and pilot jets? The manual I got off the net states main: 162 and pilot: 45, however the guide from RMATV states main:150 and pilot: 70.

 

Perhaps it is not necessary to know as I will be chaining them out when I get the AIS kit but I wonder if the jets with the AIS kit are the right ones for my riding area. I ride at ~4k-9,10k and wonder if the JD jetting kit will be a better choice. 

 

Sorry for all the questions intertwined but I just wanted to do all my research. 

 

Thanks everyone. 

Edited by jentzschman

165

45

50 leak

70 air jet (if ACV remains active. 100 if not)

NCVS needle 3rd clip ( or stock YZ needle)

2008 crf450r apump upgrade kit from crfsonly.com

Tokyo mods apump linkage upgrade spring

uncork intake

uncork exahuast

unplug tps

R&D remote fuel screw

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