“Popping” on the Trail

Dear Ralph:

Please help me! I have a 92 RXL. The problem is that I can’t trail ride it. Running it hard on the lakes is just fine, but when you are on the trail it starts to “pop”, even when the plugs are new. Everything else is set to factory specs. Nobody seems to have an answer.
Robin Woolner
Schreiber, ONT

Popping and backfiring can be caused by different things. The first place to check would have been the plugs, but you’ve taken care of that. If there was water in your fuel or if you had a sticky injector the problem would be there all of the time. The key here is that it “pops” only when trail riding. Because of this, the most likely cause is the throttle safety switch system. Its basic function is to cut the ignition if the switches detect that the carbs (or throttle bodies) are open when the throttle is closed. When ignition is cut and turned back on, backfiring and popping is common. On the RXL, one switch detects if the throttle lever is all the way against the block (closed). The other switch is up at the pivot pin. This switch is normally open, and closes when pressure is applied to the throttle lever (at the same time the block switch opens.) If the block switch opens and the pivot switch is still open, the ignition will be cut. Verify the proper operation of this system and recheck the safety switch adjustments. The other scenario I’ve seen is with the way riders hang on to the handlebars. Some people “push” on the handlebars (and the throttle lever) as they hang on, applying pressure to the pivot pin. This pressure can keep the pin from moving and closing the pivot switch, ala the “pop”.