98 WR400 Freshen/Build/Sumo etc... With some questions.

1 reply to this topic
  • Gcsf

Posted February 05, 2014 - 12:08 PM


Introductory post here...


My name is Grant, and I just bought a 98 WR400 that was parked running about 3 years ago but it had gas in it. The throttle was glued shut, the fuel shutoff valve was glued in the off position, and the gas in the tank was bad enough it looked like Mtn Dew concentrate, and smelled worse than any chemical I have ever come across in the oilfield.


So, I started cleaning things.


1. Tipped the bike over and drained the gas out of the tank. Let me just say this. After having only had supersport street bikes it feels REALLY weird to lay a bike down on its side and then pick it up on the seat and handle bars... (Probably better ways to drain it, but I was just working on getting things cleaned in a hurry that day).


2. Took the fuel shutoff switch apart and cleaned the dark brown tar looking gunk out. That took some effort. Put the valve back together and it was leaking so after a little information from a friend, I took it back apart and put it back together letting the screws and the washer set the depth (instead of pushing it in first, then tightening down) and voila, it doesn't leak anymore.


3. Took the plug off the bottom of the carb and ran some fresh gas through the system to flush it out. After I got clean gas coming out of the bottom of the carb, I was able to work the throttle loose, and with some more gas and working it around it is now free.


Tried kicking it over for a bit, but got nothing. I expect the jets and every other part of the carb are grossly gunked up as well.


So, that leads me to my questions...


1. I think I am better going with an 03-11 YZF450 carb than putting any work into the factory carb. Is this true? 

2. As long as the part numbers match what is on a YZF400, does one of these carbs off of a 450 ATV work as well?

3. What do I need to source, besides the carb, for the carb swap? Cables, Throttles, adapters, etc?

4. Is there a preferable year for those carbs?


Plans for the bike:


1. Get it running.

2. Ride it for the fun of it during the snow and winter with the knobbies.

3. Supermoto it, and goof off with it, both on the street, and at the local cart track.

4. I needed a winter project, and for the price I paid, why not? lol...


Pictures to come later.

Any information about the carb, supermoto parts, or other potential needs of this bike are very welcome. I know fuel injected supersports pretty well, but not so much the carb'd dirtbike world.


Thanks in advance!

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  • flyandride

Posted February 05, 2014 - 12:30 PM


I've brought back carbs from the dead by soaking in Pine Sol.  It won't hurt the rubber parts like carb cleaner will.  So  don't give up on it yet.  Take it apart but not at mid body where there are torx screws.  Squirt Pine Sol into the passages where you can't take it apart and let it soak, blow out with compressed air.  You might have to work on the jets with a strand from copper wire.  


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