03 WR450 (no low end?)


4 replies to this topic
  • mxchic

Posted June 04, 2004 - 07:08 AM

#1

Well I am normally on the 250F but I need a little info on the 450F. A guy I know (who is used to riding old school yamahas) just bought a new WR450F (an 03 I believe). He had the dealer put on the exhaust tip & throttle stop, but other than that he is not sure what else they did as far as jetting or grey wire. He said the thing has got "no low end". :thumbsup: It sounds crazy that a 4 stroke 450 would be lacking in the low end dept. I am assuming that it is a jetting/carb problem. The things want to stall at low RMP and is a pain to start.

My husband did the grey wire on his 250f and loved the difference. My brother-inlaw did it on his 426 and hated it because he lost a lot of low end, and sputtered at low RPM's. Did any of you feel that you lost low end after cutting the grey wire?

We are planning on tearing apart the carb and seeing what in there. We are assuming we may need to just richen the pilot, maybe the MJ, and go from there. I am going to see If I can talk him into the JD jetting kit. We will also check the grey wire.

How does the WR450F low end torque compare to an XR400? I know I am comparing apples to oranges, but the race bikes perform with better responce and Yamaha's are known to hit harder. If you are used to old school smoother more gradual power, maybe it feels like it has less smooth low end. I am just guessing here. Any advice you can lend is much appreciated. :awww:

  • gomopar440

Posted June 04, 2004 - 07:37 AM

#2

Are you referring to a bog right after twisting the throttle? Cause that has been known problem. Look up the accelerator pump in the search to find LOTS of posts on that subject here. Hope this helps.

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  • mxchic

Posted June 04, 2004 - 08:59 AM

#3

Are you referring to a bog right after twisting the throttle? Cause that has been known problem. Look up the accelerator pump in the search to find LOTS of posts on that subject here. Hope this helps.


Ya, I know about the bog fixes, my husband and I took a lot of time tuning his ap squirt to get the correct response. I don't think that is what he is talking about. He is decribing problems steadily rolling on the throttle & stalling at low RPMs. I know I just need more info to really know what is going on. I thought we would start with jetting. :thumbsup:

  • RichBaker

Posted June 04, 2004 - 01:40 PM

#4

My 03WR450 has plenty of bottom end, so much that I put a 15t front sprocket on.....I ride 3rd and 4th gear mostly in the dez. no problem!
It has better bottom-end power than my old XR600....and LOTS more top-end!! :thumbsup:

  • mxchic

Posted June 05, 2004 - 03:51 AM

#5

My 03WR450 has plenty of bottom end, so much that I put a 15t front sprocket on.....I ride 3rd and 4th gear mostly in the dez. no problem!
It has better bottom-end power than my old XR600....and LOTS more top-end!! :thumbsup:


Yah, the bike is probably just not running right. Who ever did the mods didn't take the time to really tune up the carb. I think the guy is going to get the JD jetting kit, most poeple I know are very happy with it even when there jetting felt good. We figured the JD kit would be a great starting point to getting this bike running correctly.




 
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