2003 wr450f has low rev limiter at all times

7 replies to this topic
  • yamhammer

Posted April 16, 2016 - 04:31 PM


Hi noob here.
Got a 2003 wr450f a little bit ago. Rode it in the dirt with no qualms twice. Being a noob I never got in it real hard.
Put a street legal kit on it.
First time I rode it on asphalt I notice what doesn't seem right.

I read somewhere about a 7500 rpm limiter that kicks in on neutral and supposed to be 12k or so in gear.

It just feels like it's hitting at what must be 7500- I have no tach for a 1 cyl...

In first it hits the limit around 25, second is almost useless, 4th and 5th finally don't seem too bothered by it around freeway speeds.

Certainly can barely consider popping the front wheel up.

Runs great otherwise. It just gets the telltale flatline rpm, hard miss of a limiter. Seems to make no difference what gear it's in, same rpm in neutral.

With neutral switch connected or undone.

Neutral led on speedo I installed indicates neutral switch works properly.

I have also checked that the light is not causing this. It was my first thought, cut the wire to the light on the side of road, made no difference.

Read about neutral wire to ecu could be undone to do some strange trickery and undo neutral limit. Not sure I wanna do that either but could be good tinkering for diagnosis



  • still2smokin

Posted April 16, 2016 - 07:05 PM


Pretty sure the rev limiter does not kick in until 11,000-11,500. 


You have something else going on , first clean the carb .....gently , no Chem dip or actual carb cleaner .

Download a manual from Yamaha , link is the FAQ section . 


Change your plug and using the Yamaha manual , test the electrical components and then check the

valve clearances . I had a similar issue that ended up being a bad connector to the coil .


Tons and tons of good info here in the WR section is easily had if you do some searching .


Look for and be wary of crap work the PO did .


I am sure other people have more but this is where I would start

Edited by still2smokin, April 16, 2016 - 07:11 PM.

  • Krannie McKranface

Posted April 16, 2016 - 07:27 PM


25 mph in first is very high revs in first gear with stock gearing 13/51.....like waaay too high.


In first gear you should be shifting in about 1.0 seconds....at full throttle......maybe less...


On a 2003 WR450 that is uncorked, there is no power after about 6500 rpms, and it's pointless to go up to the rev limiter !


Why the hell are you testing for a rev limiter in neutral !!! ???  You should never, ever, do that !


You must come from the in-line-four street bike world.....but it's WRONG to do it on those bikes too.....

  • toten

Posted April 16, 2016 - 09:17 PM


I had mine act similarly due to a poorly installed dual sport kit. My lighting was swapped over to the DC side (so it could run with the bike off), but my charging system wasn't changed, so riding with the lights on would drain the battery to the point ignition would cut. For some reason it ran ok at low rpm, but then would cut out at way lower rpm than it should. Lights off it was fine. Don't know if it's what you have, just what mine did.

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  • yamhammer

Posted April 16, 2016 - 09:55 PM


I read the neutral limit kicks in at 7500. It feels like this is tops all the time. Under load or in neutral (yeah I know)

I'd rather not dive into a rabbit hole of unneeded maintenance.
But I'm not against maintenance either. Just afraid of needlessly screwing up seals or adjustments. everything I touch always leaks. It's my curse.

What exactly was it doing with bad coil connector?

Pointless to go to limiter. Except I can't hardly go with any level of Scoot without getting into it in 1st and 2nd.
I dunno what 11k sounds like but this sure isn't it.

I don't need to hang out at 11k all day I'd just rather not get cut off so low if it (sure doesn't seem) ain't right.

I got the dualsport kit, but the headlight runs from factory source. Only works with engine running.

Interesting point however

Oh. And I tried the sky blue wire disconnect mod, makes literally no difference in gear or neutral

  • andrewzac

Posted April 17, 2016 - 09:40 PM


HI.  check with previous owner if they did valve clearance.   if your bike is hard to start you will need to do the valves ,if he did them then he has  cam timing out by 1 tooth , that is the symptom of hitting rev  limiter early.  you will need to check your timing . hope this help ,  andrew

  • andrewzac

Posted April 17, 2016 - 09:45 PM


bike hard to start , valves are out of speck .  low rev timing out 1 tooth , check both .  

  • yamhammer

Posted April 17, 2016 - 09:47 PM


Interesting point for sure. On the other hand there are the guys that skip a tooth on exhaust to make yz?
So theoretically it may be a tooth off in the opposite direction of an improvement

It starts pretty easy. Cranks right up with the e-start.
I have yet to succeed with the kicker but my buddy proved it's just me, kicked it right up.


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