07 YZ450 vs 09 YZ450

Saturday I rode with a friend at Gorman. We rode the track and also rode some trails later in the afternoon. My bike (07) ran great all day long and my friend offered if I wanted to ride his (09) for a bit. After a few laps around the track I was not happy with his bike. He has left the bike completely stock, still has the original tires and sprockets. Under 20 hours for sure. His bike could not be lugged around in 3rd gear around any of the corners like my bike can. The power of the 09 felt like that of a 2-stroke. My friend rode my bike and was completely surprised at how much power and torque it had on the bottom end.

Now from what I've gathered the 09 muffler can is restrictive and using a 07 stock can would be more beneficial? We're also gonna try looking into his carb and see if any of the jets are clogged up or wrong size. I think were also gonna get an adjustable fuel screw to dial it in while at the track. Are there any other minor changes we can make to match the power of the 07?

The cams in the '08/'09 are in fact different from the '07 (which is different from the '06), and are biased toward slightly more top end. That's easy enough to change, but the effect of the cams is not as significant to your complaint as the exhaust system and CDI are.

Virtually any exhaust from a cheap slip-on on up will improve things noticeably at around 5000 RPM. IMO, you'll get the biggest bang for the buck with either a DRD stainless or an MRD full system (the latter can be ordered on a custom basis to do more or less anything you want it to).

The other part of the equation is the timing map built into the CDI. Your best bet is to get one from an '06, but they've gotten rather popular, and the prices have moved up quite a bit. The '07 is better than the '09, but not like the '06.

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