08 Wrf450 bad judder under 3500-4000 revs, can't be normal ?.


9 replies to this topic
  • chicargo

Posted September 11, 2014 - 07:44 AM

#1

Hi, I've got a 08 wr450f, it's got around 3000 miles on the clock. I bought the bike 3-4 months ago and due to a restricted licence I've only just got it on the road and ridden it.
The problem is that if you open up the throttle while under 3500-4000 revs the bike judders like crazy, once you've passed the 3500-4000 rev mark the juddering stops.
The juddering is kind of like a car would judder/kangaroo if you were doing 20 mph in fifth gear.
Is this normal ?.
Other than the juddering the bike sounds and rides spot on.
Any advice would be greatly apreiciated.

  • revelc

Posted September 11, 2014 - 10:34 AM

#2

Hi, I've got a 08 wr450f, it's got around 3000 miles on the clock. I bought the bike 3-4 months ago and due to a restricted licence I've only just got it on the road and ridden it.
The problem is that if you open up the throttle while under 3500-4000 revs the bike judders like crazy, once you've passed the 3500-4000 rev mark the juddering stops.
The juddering is kind of like a car would judder/kangaroo if you were doing 20 mph in fifth gear.
Is this normal ?.
Other than the juddering the bike sounds and rides spot on.
Any advice would be greatly apreiciated.


Do you mean it's bucking or bogging?


2014 WRR R.I.Pieces
2012 WR450F ECU, GYTR tuner, Yoshi RS4, MSR rad guards, Cycra Pros, and a growing wish list...

  • stevethe

Posted September 11, 2014 - 10:58 AM

#3

Sounds like the WR 450 studder. Dynatek ignition fixes it. Do a goggle search.

  • chicargo

Posted September 11, 2014 - 11:44 AM

#4

Hi fella's cheers for the replies, it's hard to describe Feels a bit like gear lash back. If your behind a car doing 30mph it's almost imposible to to hold it steady, the bike jerks forward and back, If I slam it in second gear and keep the revs at 4500-5000 it smooths out. Don't think it's the gears ? as does it in all gears.
If your at low revs and twist the throttle it sounds and feels like somebody's rapidly hitting the bottom of the bike with a rubber hammer.

  • chicargo

Posted September 11, 2014 - 11:53 AM

#5

Just googled studder as stevethe suggested and it could be that, I'm gonna try unplugging the throttle position sensor on the carb tomorrow and see how it goes. Be great if it improves it as it's really annoying.
I'll post the results tomorrow. Cheers fella's

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  • stevethe

Posted September 11, 2014 - 01:28 PM

#6

They also chain slap in higher gears at low throttle openings. Double check your chain adjustment.



  • Krannie McKranface

Posted September 12, 2014 - 02:05 AM

#7

Your description makes it difficult to give you specific advice



  • ThumpMe

Posted September 12, 2014 - 07:20 AM

#8

Good suggestion from stevethe about chain slap. Might be the solution if out of adjustment or a very worn chain.

 

 I recently went through a long three month ordeal getting the clutch on my '03 WR to work correctly.

 

 At one point I removed the judder rings in the clutch and replaced it with another full size clutch plate. This is how the YZ clutches come from the factory, and I was grabbing at straws trying to fix the WR.

 

 With the judder rings removed and replaced with another clutch plate  it had a feel a whole like what you are describing. It would mostly do it at slow speeds and takeoffs, or while feathering the clutch and was  especially noticeable when on wet surfaces. Do not know if this could be what you are feeling but I had never experienced anything like this before. It felt and sounded pretty awful!  It is pretty easy to check though and since lots of folks complain about the clutches on these scooters, more than a  few have had people go into them trying to get better clutch actuation. Maybe someone tried this "fix" on yours?

 

 Good luck and  keep us posted as to what you find..



  • chicargo

Posted September 12, 2014 - 07:47 AM

#9

Cheers for the help and input guys, just got back from seeing Owen at manchester extreme, he had a spin on it and said it was caused by chain slap due to having a far to small rear sprocket (39 teeth) and a 13 tooth sprocket on the front. Good call stevethe. He also said there was a little cam chain noise so I've booked it in for Wednesday to have the cam chain replaced and get the valve clearances checked. Other than that he said the engine felt good and pulled well, So with new sprockets should be miles better, I'll update this post when I slam the new sprockets on. All the best, chicargo
P.s I tried unplugging the tps and didn't make that much difference

Edited by chicargo, September 12, 2014 - 09:38 AM.


  • chicargo

Posted January 19, 2015 - 02:47 PM

#10

Update......the thing I've found that made a fair difference to the shudder was the fuel mixture screw, I've enriched it a bit and now no way near as bad.




 
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