02YZ426F (and other YZ) carburetor - doesn't like steady throttle?

7 replies to this topic
  • rufusz

Posted August 24, 2009 - 01:06 AM


Hi guys,

I've read somewhere that the carburetors installed on the YZ's (generally cross bikes) aren't optimized, or don't like if you ride on steady throttle (constant throttle, let's say at 50, 60, 70%). Is this true or it's only a myth?
Nowadays, I've noticed that the engine sounds much better when riding in MX style instead of steady throttle like enduro/SM style...or it's just me noticing weird stuff? :ride:

  • Anssi

Posted August 24, 2009 - 07:02 AM


Four-strokes don't mind being run on steady throttle.

  • grayracer513

Posted August 24, 2009 - 07:04 AM


Mine runs fine at a cruise. Don't know what you mean.

  • MuDPoUNdeR

Posted August 24, 2009 - 07:16 PM


just keep a steady wrist! haha

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  • rufusz

Posted August 25, 2009 - 12:33 AM


It sounds like it's getting too much fuel and it really asks for that throttle to be opened wide.... or maybe this is normal and I'm dumb, so thread can be closed :ride:

  • grayracer513

Posted August 25, 2009 - 05:55 AM


If it's running rough at a cruise, and the symptoms indicate it's too rich, try lowering the needle a step. You can also try a needle with the next larger upper diameter, or perhaps your main jet is simply too large.

  • rufusz

Posted August 26, 2009 - 03:26 AM


If it's running rough at a cruise, and the symptoms indicate it's too rich

What are the "too rich" symptoms?

  • grayracer513

Posted August 26, 2009 - 06:44 AM


If it misses because it's too rich, the miss will tend to be regular in rhythm, whereas missing from being lean tends to be erratic and irregular.


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