Carbs / Intake

• "jet kit" There are two jet kits on the market: one from DynoJet / K&N and another by a company called Factroy Pro. These jet kits really help cure the carbureted 2V motor's lean running. You'll find cold running is greatly improved with much faster warm-up. Overall, the bike will feel more responsive, but power isn't dramatically improved. With careful setup and dyno tuning, up to 75 horsepower is attainable.

  Jet kits are OK but pretty lame in the big picture. With the Dynojet kit, run the stock jets, and set the fuel mixture screws to about 4 turns, but otherwise follow the Dynojet instructions.

• Air box rings The ProItalia airbox ring really helped to wake up my bike's performance with the Stage II jet kit and added amazingly to its sound. But since it is a stock airbox that's been hacked a little too low, it is a bit flimsy, requiring me to safety wire the metal straps that secure the ring to the airbox. K&N / DynoJet makes an aluminum unit (also sold by FBF) that was based off the bottom of the stock box that looks great and didn't flex at all. Problem is that they don't always seem to fit. An aftermarket piece that seems to work is that offered by www.drdesmo.com.

  We just cut back customers' air box lids a little bit higher and results in a more rigid frame.

• Keihin 41mm Dual FCR kit Definately the first performance part you should put on your bike! Skip the jet kit, save the $$ you'd blow on that and just get the carbs. Even if you have to run them with stock pipes. Read what I have to say about them in the FCR FAQ. Don't be a puss, just get them.

  The individual 41 FCRs on the short Malossi manifolds absolutely kick butt in conjunction with extreme headwork and the Staintune spaghetti system! Insane torque and unlimited top end. With all the work I did to the heads, you'd think that mid-range torque would suffer, but NO! The thing pulls way hard. It just grabs your butt and flings you forward. Look at the rebuild and engine parts pages for some pics.

  While the Malossi short intakes and single FCRs (pic) are powerful, I don't think their gains warrant installing them on a street bike. You must have extreme head work and the spaghetti system to take advantage of the extra flow. I totally recommend the dual FCRs for 98% of the people out there. Keep in mind that the difference between the single FCRs and short intakes and the dual kit is not that big of a step. Other than increased throttle pull, you may not even be able to differentiate between the two while riding.

  Head work is pretty impressive: simple cleanup combined with FCRs and the spaghetti system, the 2V motor's horsepower peak moves up to near 8500 rpm and has a useful overrev up to 10,000 rpm. If you pay someone $2000~3000 to change the angle in the ports, you'll be able to break into the 90s. I've seen claims of 97 and more hp from a carbureted 900 2V motor.

• K&N O2 sensor and air/fuel meter The only way I finally figured out that the needles were waay off on the singles kit was with these aids. Pics: O2 sensor and K&N ratio meter.