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Skip

A quick blip of the thottle and the engine dies

10 posts in this topic

Hope you guys can help. I have a stock '00 WR400, I just broke in the engine, I also just cut down the rev limiter screw to the recommended height (some peole say 8.5mm others say 9mm, I cut it down to 9mm to play it safe)

Now when I give a quick blip of the the thottle to about 1/4 open the engine dies. The rev limiter doesn't have any thing to do with this,right? I checked the needle seat to see if there was any grit in it, there wasn't, should I raise the needle up or down? It has the the stock jets in it.

The bike is extremely clean too, as in the airfilter/airbox

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There are lots of jetting stuff on the site just search but I will offer the following to get you started.

Put in a 48 pilot jet

Run the fuel screw at 1.5 turns out

use a minimum of a 175 main jet

Run the stock DRS needle in the #4 or #5

You really should ditch the stock DRS needle and run a DVP in the #5 or #4 slot.

Should be good for sea level to 4000 ft of altitude.

Happy Trails

Clark

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make sur ethat when you open the throttle your accelerator pump jet is squirting fuel. Taffy

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mine was doing the same thing I had to clean my excelerator pump... or how ever you spell it .... the rod that goes into the pump gets dust and dirt in it so try that

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Originally posted by Skip:

Hope you guys can help. I have a stock '00 WR400, I just broke in the engine, I also just cut down the rev limiter screw to the recommended height (some peole say 8.5mm others say 9mm, I cut it down to 9mm to play it safe)

Now when I give a quick blip of the the thottle to about 1/4 open the engine dies. The rev limiter doesn't have any thing to do with this,right? I checked the needle seat to see if there was any grit in it, there wasn't, should I raise the needle up or down? It has the the stock jets in it.

The bike is extremely clean too, as in the airfilter/airbox

I have the same thing with my WR and I have tried to cure it, there is no cure, the four stroke will always have this hesitation it is not like a two stroke. You can try richen up the pilot jet but that is about it. When you ride the bike the hesitation is gone because the higher rpm's. but from a idle and you wick the throttle it will hesitate or die. Just once in a while I can get a hesitation on accel when I am riding on a track but that is it. If you do find a cure post it for me.

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I think I fixed it. I dropped the 'e' clip down one slot (#4) richened it up a bit it seems to work with the stock jets. It seems to be running fine. The neighbors hate me though from 'testing' all weekend. Oh one more thing. I know on mine the rev limiter was cut wrong,am I the only one? (the dealer said 8.5mm from the bottom of the head) the end of the bolt comes no where near the stop.To keep from over reving it. I got a new bolt (12mm) from the bottom of the head. This (at least on mine) works. I've read that everyone is using pliers to remove this limiter it's a 5mm allen bolt on mine. I just used an allen key it came right out. Maybe 5 min at the most. Keihin slide carb. The picture on the web page I looked at looks like a different carb than mine ('00) Sorry I'm new to this bike, like most of us. Thanks for this kick ass page guys/(girls?) I'm so used to 2 strokes, taking a bit to get used to. I DO like NOT fowling plugs all of the time!

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Originally posted by Greg C.:

Skip why mess with cutting the throttle stop? Just buy the one for the 426 and install it! :)

Well it's done now!!! Thanks anyway

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Originally posted by Skip:

Hope you guys can help. I have a stock '00 WR400, I just broke in the engine, I also just cut down the rev limiter screw to the recommended height (some peole say 8.5mm others say 9mm, I cut it down to 9mm to play it safe)

Now when I give a quick blip of the the thottle to about 1/4 open the engine dies. The rev limiter doesn't have any thing to do with this,right? I checked the needle seat to see if there was any grit in it, there wasn't, should I raise the needle up or down? It has the the stock jets in it.

The bike is extremely clean too, as in the airfilter/airbox

Just let you know It's working great now. I listed below what I did. Of coarse I'll have too play with it again when I switch the timing to YZ and a better pipe.

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