Sputtering in 5th gear on a 2000 WR400

I have beaten this with a dead horse already and am getting very frustrated. I have tried just about every conceivable jetting combination and nothing has worked. The bike still sputters and then takes off then sputters and takes off only in 5th gear. I can gradually give it gas through out the sputtering to eventually get it up to speed. The sputtering starts from as little as 1/8 throttle all the way up. What else besides jetting could be causing this?

Again, this ONLY affects 5th gear. The bike runs very smooth up to 4th gear with plenty of power and no sputtering. I figured if it was the clutch it would affect all gears. I can lug this up a hill in 3rd and still not slip. I tried every which way to get it to happen in other gears this last weekend. I even put a new spark plug in before I rode. Any suggestions please! I am running out of patience.

Just a thought - are you sure you are not just riding too slow (lugging the motor) for the gear. My 99 WR400 with 14/48 gearing doesn't like anything less than ~40 mph in 5th. It behaves like a car that's in too high a gear for the speed.

Are you sure you don't have a missing tooth on one of the 5th gears.

I know the first time I did a gearbox in I thought I had some sort of electrical miss.

If its only fifth gear then the only things diferent in that situation is the gear box or some sort electrical situation with the neutral switch.

The neutral switch is easy to disconnect - see all the blue wire mod stuff.

I disconnected the neutral switch the day I bought the bike, so I know that is not it. As for lugging it, it happens going from wide open 4th gear shifting into 5th gear will immediately cause this problem.

Do you have to split the case to check to see if the gears are broken or can you just remove the clutch cover?

Well the easiest way is to see a tooth on a magnetic drain plug or when changing oil.

But a visual inspection unfortunitely requires splitting the cases.

When i bought my WR426 last fall, the 5gear was skipping... the guy who sold it to me had changed the fork and was still skipping. I chaged the 5th gear and 3rd gear, cause they enters each other by their side. There was only a little bit of wearing on these gears and that was all it was needing to make the gear skip when smashing the throttle in 5th. only way to know is tearing down the engine... that take several hours to do.<

Now everything works fine! :)

Do you have any way of securing the baike to stand and firing it off? If so try it and run it thru the gears tosee what happens when there isn't any load on the bike. You may be able to hear if it is inside the tranny or tell if it is an electrical issue.

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