2001 Honda XR400 Carburetor woes...

If you recall, when I purchased the Honda XR400 from Willie, it had been sitting in a barn in Ontario for some time. A bit longer than I care to recall in fact, and certainly long enough for some problems to occur that I hadn't counted on.

  • The fuel really couldn't be called "fuel" any longer, but could be described as "varnish" and "gum", especially in the carburetor. 
  • The float needle valve was firmly glued into it's seat and wouldn't move at all. 
  • The float needle valve spring was weak and wouldn't hold the valve closed under normal gravity pressure. 
  • The OEM Honda fuel petcock's plastic fuel filter/screen in the Clarke tank had deteriorated and was in pieces at the bottom of the tank lying in the crud (see above) 
The carb float bowl, bottom half
I had to use about 80lbs psi of shop air to blow out that float needle valve, and then clean up the seat so the new valve would have enough slip to work properly.

Those floats need to be checked for buoyancy and adjusted to a min max height 

Dirt in the fuel or the fuel turned to dirt. *sigh*

KVN-19S30 Aftermarket replacement float needle
 Anyhow, I thought I cleaned all of that out and installed the new float needle valve properly, but after reassembly it is still pissing fuel everywhere. 

I'm going to have it off again and focus on debris above the float needle this time. I'll install an inline fuel filter between the petcock and the inlet to prevent it happening in the future, and give the carb a really good going over to see if I have it sorted. Then it's off to a professional if I can't get this garbage fixed. :'(

I think I need to rehab the fuel petcock as well:


Some resources I found helpful are here:





Something to help you see it all "(18) Float Valve" is what I replaced

Here is the culprit after marking it's spot. It reminds me of a dog marking it's territory.
That my friends, is a PITA

The bike marks it's spot

Wish me luck!

And it LIVES again!!!

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