ing a 2007 WR450F so newbie questions

7 replies to this topic
  • pschiess

Posted April 19, 2011 - 09:03 PM


The bike is stock with the free mods done. Needs tires and chain as they are all original. What do you recommend for bike protection (skid plate etc)? What are the general must do mods (other than the free mods)? The bike is in California if that matters. Will be used as a trail bike and NOT a race bike. To be used for single track trails. I am 6'1" and weigh about 210. Thanks for any suggestions.

  • MANIAC998

Posted April 20, 2011 - 03:22 AM


At your height & weight, you might want to get the suspension done. They are notoriously soft stock, and I'm 6'/185 lb. But since your only going to trail ride it, it isn't a must do, but you'll never get it to handle the way Yamaha designed it unless you do. I've got the Yamaha GYTR skidplate on mine, and it's perfect! Definately get some radiator guards too. You will wreck those rad's without some protection. Don't ask me how I know!!! Maniac

  • RockyMtnScotsman

Posted April 20, 2011 - 06:58 PM


brush guards to protect the levers and your hands

maybe just me, but anytime I buy a used vehicle I change ALL the fluids so I know what's in there

  • cage

Posted April 21, 2011 - 12:00 PM


This is more maintenance-minded than anything else, but since you have the back wheel off for the tire/chain/sprockets, I would strongly suggest taking the swingarm/linkages/rear shock off and inspect the bearings. All of mine were completely gone...I am so glad I did not ignore this!!!!

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  • YamaLink

Posted April 24, 2011 - 09:08 AM


Get it properly sprung. At 210 pounds of muscle there's no way the 100mm of sag is being achieved. Your bike, even at trail riding pace, is understeerin, wallowing and bottoming out.

Slap on some brush guards, maybe wire the rear brake pedal to the frame, a skidplate....

  • jshepherd61

Posted April 26, 2011 - 01:26 PM


Ok so I just bought a new 2009 WR450F unfortunately I'm a fuel injection tuner been a while since I worked on a tin can (carb). I started to ask a few questions after I did the free mods; air box, new FMF pipe, AIS GYTR, R&D Powerbowl 2, R&D Acc pump, Grey Wire, K&N filter. On how to jett this thing, I live in Colorado and ride between 6500 - 11000'. So after searching and reading all of the posts especially the one directed at the newbies to check the posts, threads and sticky's. I've cut and pasted all of the prevalent information and have come up with some results which confuse you even more! My findings, Oh and by the way my last job was EFI tuning for Esteban Guerrieri in the IRL Indy lights so I'm not trying to be a SA just looking for help. Back to what I've found in the WR450 Intake - Jetting / Fuel Injection and Jetting table;

6000 - 11000'
Main jet: ranges from 150 to 168
Pilot jet: ranges from 40 to 50
Pilot AJ: ranges from 65 to 85
Leak Jet: ranges from 45 to 55
Starter Jet: ranges from 58 to 67
Fuel Screw: 1 1/4 to 2 (only consistent setting)
Needle clip depending on type but all using the GYTR anywhere from 2 to 4

Ok these are the variances for the same bike same 6,000 to 10,000 at 70 - 90 degrees. I know ever bike is different but not as much as these variances and they all run great! Can anyone help me with a good starting point that has recorded the AFRs and VEs in these altitudes?

  • pschiess

Posted April 26, 2011 - 03:00 PM


Great question. I found articles in Dirt Bike magazine that had similar jetting differences.
Needle - NFLQ 5th or NCVQ 4th or DTR 4th
Main - 168 or 162 or 170
Pilot - 48 or 48 or 50
Leak Jet Screw 45 3/4 turn out
Accelerator pump 1/2 turn in
Air Screw 110

  • 066logger

Posted April 27, 2011 - 07:15 PM


JD jetting kit. period. problem solved. im a believer after just installing mine :thumbsup:. its 75 bucks but the best 75 bucks that ive spent on carbys so far. oh and i used the thickest O ring and wow so much for bog lol. oh and r@d flex fuel screw. a bit pricy but sooo worth it. just whatever you do dont buy a cheap extended fuel screw that has an aluminum tip. i used one and it came loose and galled the threads and that carby became a paper weight :cheers::thumbsup:.


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