An all too common myth is the "rejet the carbs because..." myth. Because of altitude. Because of an aftermarket exhaust. Because the factory made the carbs too lean. Because it just doesn't run right. Because someone told me so. Like deer whistles, high-voltage ignitions, and little bells hanging from your footpeg, this is fallacy, folklore, superstition.

Hondas having constant velocity (CV) carburetors are not affected in the same way non-CV carbed ones are. Essentially, they are self-compensating for altitude. This is easily explained by how CVs work. The slides lift in response to the difference in pressure between manifold pressure and atmospheric pressure. And since both change equally with altitude, there is no net change in the pressure differential. The only places in function the CV carb does not self-adjust is at the two places where the slide doesn't move: idle and wide open. And yes, there is an advantage to a slight rejetting for those two places, but not a performance one, only an emissions one. Honda themselves said this if you don't believe me. If you feel your bike performs poorly at altitude, it is not necessarily something that can be fixed by carb alteration. Your CV-equipped bike is under-powered at altitude due to the reduced oxygen that in turn reduces cylinder compression. It has nothing to do with carburetion and cannot be fixed through that means.

The only exhausts which upset the carburetion of most vintage Hondas are those with no baffles. The insistence otherwise is a clasic and now ancient untruth.

Equally fallacious is the oft-repeated idea that Honda made their bikes too lean. In fact, like every motor vehicle manufacturer, if anything they are a little rich. Industry professionals are well aware of this.

It is sadly a pervasive falsehood that performance shortcomings can be solved by carburetor modification. The fact that is lost in this deception is that virtually every case where a jet kit solved a running issue it was through covering up (with a flood of fuel) a maintenance need. That is, the maintenance item should have been attended to and the jet kit would never have seemed so necessary. Note this if nothing else: Non-maintenance is responsible for virtually all that ills vintage Hondas. It is the least performed and the least valued. Don't believe it? Answer these questions. How much cylinder compression does your bike have? What are your valve clearances? Are you using fuel stabilizer continuously? What is the pilot screw setting? How and how often are you synchronizing your carburetors? What concerns you more, ethanol or maintenance?