Sign in to follow this  
Followers 0
x_JT_x

04 wr450 surging

37 posts in this topic

Just went on my first ride with my 04 wr450f. It's having an issue where it surges any time it's past idle, unless you rev it quickly. Seems like a constant rev limiter everywhere. Also is sucking gas WAY faster than the other 3 I am riding with. Playing with the air screw changes it a little but can't eliminate it. Idles highest with air screw ALL the way in if that helps.

Mods done are only the pipe tip. Not airbox, maybe not even rejetted but I can't know for sure. Riding at 4k feet. Will be ridden between 2-6k mostly. Any advice on how to fix?

Share this post


Link to post
Share on other sites

You have to get into the carb and determine the jetting

It sounds like your pilot is too big: you want a 45

 

The minor surging at partial throttle is part of a known problem with all Wr's. The ignition module wanders at certain rpms.

You can reduce it by unplugging the TPS harness

 

Read the FAQ section at the top of the forum.

Share this post


Link to post
Share on other sites

That's a fuel screw.  Turning it in makes it leaner.  If you need it all the way in, the pilot jet is too big.  

Share this post


Link to post
Share on other sites

That's a fuel screw. Turning it in makes it leaner. If you need it all the way in, the pilot jet is too big.

Dropped the needle two notches and most of it seems better. Still has it under half throttle

Share this post


Link to post
Share on other sites

Yes, if you search 'stuttering' or 'surging' or 'rough running' in this forum, you will have enough reading for a year....

Share this post


Link to post
Share on other sites

Yes, if you search 'stuttering' or 'surging' or 'rough running' in this forum, you will have enough reading for a year....

Yes, but I am by no means good with jetting so I did what the forum is made for and asked for help. I basically want to know what jetting should be for previously posted elevation, opened airbox and gytr pipe tip as that is what I will be doing (already has the tip)

I'm well aware there is enough reading and almost none of it is relevant to my issue. If it's a known issue someone should do a write up, lots of great people who could I'm sure.

Share this post


Link to post
Share on other sites

You have to get into the carb and determine the jetting

It sounds like your pilot is too big: you want a 45

The minor surging at partial throttle is part of a known problem with all Wr's. The ignition module wanders at certain rpms.

You can reduce it by unplugging the TPS harness

Read the FAQ section at the top of the forum.

Apparently the guy I got it from thought it was the tps because it was already unplugged. I plugged it back in since it made No difference.

Share this post


Link to post
Share on other sites

Not only do I think your pilot is to large, but I'm guessing your float's are off too. Since you mentioned that your burning WAY more fuel than your buddies.

Share this post


Link to post
Share on other sites

Not only do I think your pilot is to large, but I'm guessing your float's are off too. Since you mentioned that your burning WAY more fuel than your buddies.

The rider behind me said that it smelled like a two stroke burning especially when I was riding in that misfire spot. It doesn't drip gas at all, and if the pilot were to big would I be able to one kick it? My battery died out near the end and it's a piece of cake to start up.

Share this post


Link to post
Share on other sites

Oh and by the time we did like 20 miles I hit reserve and they had over half a tank.

Share this post


Link to post
Share on other sites

Oh and by the time we did like 20 miles I hit reserve and they had over half a tank.

 

If the floats were to high, it would stall or  hesitate on rough terrain, and you would be loosing fuel out the overflow

Easy enough to check....find some stairs....

Share this post


Link to post
Share on other sites

If the floats were to high, it would stall or hesitate on rough terrain, and you would be loosing fuel out the overflow

Easy enough to check....find some stairs....

Dumps no fuel. Does it on smooth or rough terrain the same.

Share this post


Link to post
Share on other sites

I bet it's the emulsion tube (needle jet) that has 'ovaled' (worn) out, causing a large amount of un atomized fuel get into the motor at certain throttle positions

Share this post


Link to post
Share on other sites

Well, that fuel is going somewhere. And I can't imagine it being burned.

You can smell it burning really uncleanly at that rpm range. Dropping the needle for the most part fixed it. someone had raised it after doing a pipe without doing the airbox.

Share this post


Link to post
Share on other sites

I bet it's the emulsion tube (needle jet) that has 'ovaled' (worn) out, causing a large amount of un atomized fuel get into the motor at certain throttle positions

The needle was on like the 3rd from the bottom clip. It was pretty dang high. Bike only has about 500 miles on it according to the odometer and the condition of it.

Share this post


Link to post
Share on other sites

You have to get into the carb and determine the jetting

It sounds like your pilot is too big: you want a 45

The minor surging at partial throttle is part of a known problem with all Wr's. The ignition module wanders at certain rpms.

You can reduce it by unplugging the TPS harness

Read the FAQ section at the top of the forum.

Got a chance to pull the carb apart today. It's got a 165 main jet 45 pilot 65 other jet. Now I'm confused because I was expecting a big pilot jet. Need some advice, is any of this jetting wrong?

Share this post


Link to post
Share on other sites

main

pilot

starter

 

All normal

 

Change your plug

Unplug your TPS

Do a stator resistance test per the service manual

Share this post


Link to post
Share on other sites

main

pilot

starter

All normal

Change your plug

Unplug your TPS

Do a stator resistance test per the service manual

Ok. What clip should the needle be on? Dropping it 2 almost cleared up the miss, but left just a tiny bit at the bottom.

Is that jetting right for the airbox mod? I just cut the snorkel out while waiting for a response here.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0