I've read some on here about the danger of overheating and melting a piston if running a bike lean. How can I tell if I am running lean? I have a stock 87 250X.

 

Runs hot, deceleration backfire, spark plug is very light color.

 

You might also notice surging at steady throttle...

 

Question about the deceleration backfire, i get it sometimes on my 87 250x, is that something i should worry about? What should i check?

 

ive been wondering the same thing about running lean. on my recon, it is naturally throatty, and whenever i decelerate, it makes a light popping sound repeatedly and unevenly sometimes, but not what i reckognize as a backfire. its not as loud as a backfire either.

 

<div class="FTQUOTE"><begin quote>Originally posted by: Hawkman300

ive been wondering the same thing about running lean. on my recon, it is naturally throatty, and whenever i decelerate, it makes a light popping sound repeatedly and unevenly sometimes, but not what i reckognize as a backfire. its not as loud as a backfire either.</end quote></div>

The UNI air filter for the Recon, is much less restrictive than the stock one. If you are running one without a rejet....quiet likely you have added to the already lean condition it comes in from the factory.

 

<div class="FTQUOTE"><begin quote>Originally posted by: reconranger

The UNI air filter for the Recon, is much less restrictive than the stock one. If you are running one without a rejet....quiet likely you have added to the already lean condition it comes in from the factory.</end quote></div>


Ditto. Most bikes and quads are jetted lean because of the EPA *****. A little popping (intermttent) is okay, but if your idle your quad for a while it is bad. Steady/ predictable popping on decel means you are pretty lean.