Don't Forget to Jet

As the 2010 riding season starts to creep into view, I'm reminded of an experience I had regarding jetting. Actually, it was my lack of jetting knowledge that caused the problem. Let me explain.

I was riding with my brother, cousin and friends in late October of 2007. I had purchased my 2004 Honda CR250R just four months prior, when the average temperature throughout the day is in the mid nineties. When I'd bought my bike it was already jetted and didn't need any adjustments. Where I come from, riding from the months of June to September doesn't require any major jetting adjustments, other than an occasional half turn on the air screw.

But late October in eastern Idaho is different. The temperature is at least ten degrees cooler than in Utah. Besides the obvious, the temperature when we were riding was somewhere in the fifties, which was too cold for my jetting setup. Although I didn't realize it at the time, my bike was running too lean. It would start after a million kicks and idle high for a while, then it would be okay. But after fouling three spark plugs in a matter of a few hours, I didn't know what to do. I didn't have any main or pilot jets, or any needles for my carburetor.

The lesson I learned was how important awareness is in the sport of motocross. Knowing the temperature outside - or where ever you may be riding - is vital to a clean, powerfully running engine. Additionally, knowing the altitude of where you ride is important. The higher the altitude, the thinner the air is. The thinner the air means the leaner you need to go on you jetting.

Hopefully you have been out already on your bike. Up here in Rexburg, Idaho, it snowed today. Needless to say, I still haven't been able to ride yet. It's a sad, sobering day today. But the day will shortly come that I'll be riding my bike instead of writing about it. Have fun!