[Drastion]

Here are the instructions that come with the kit.

And here is some info on the difference between jet kits.

It part of the difference in the qualities of various jetkits is the degree of engineering that went into determining the angle and length of the milling operations on the fluting -- the Ivan's kit for example uses 4 different millings to create the particular shape it has (while dynojet's is simply cast with a specific shape that is far courser and far more likely to be "sloppy" in it's fueling).

[The CyberPoet]

Does Ivan's rejet kit come with decent instructions? I always thought factoring in weather temp, altitude, etc, is necessary when rejetting or is that just dealing w/ 2-stoke engines?

No, that is not unique to two-stroke engines, although they are more sensitive to it than most four-strokes -- it's actually a factor of the basic carb design.

Constant Velocity [CV] carbs, such as used on the stock Katanas, are mostly self-correcting for altitude, weather, temp, etc, and should function well within about 8k feet of altitude of whatever the baseline setting is for (i.e. - one set correctly at sea level should work fine in Denver). CV carbs are easy to spot because the throttle cable(s) directly operate a butterfly in the passages of the carb, while the slide-diaphram is vacuum controlled.
Thus, while you will experience a bit of a power loss at significant altitudes due to the air simply being thinner in general (less oxygen moving into the engine), it is not an error in fueling that needs to be corrected for on CV carbs (using different sprocketing to change the gear ratios will help offset any losses).

Flat-Slide [FS] carbs, in which the throttle cable(s) directly pulls/pushes on the slide-diaphram, are preferred in racing applications because they provide faster and more direct throttle changes, but are also generally non-self-correcting for weather and altitude (which is why race teams are always fettling with the carbs to tune them spot-on-perfect for a specific track). FS carbs are also used as stock carbs in some very small engine applications (under 49cc scooters for example), because the OEM manufacturers tend to believe the odds of such a small engine experiencing signficant altitude changes are minimal (but there are CV carbs in virtually any engine size class these days).

Although FS carbs were stock in some applications, most open road-use carb'd motorcycle applications have come with OEM CV carbs for the past 25 years or so.

I was also wondering if you can buy the same size needle and jets that come Ivan's kit individually??

I am unsure if Ivan would be willing to sell you his needles separately. As I said before, his are specifically milled in an unique way (as are FactoryPro's), and are thus unavialable from anyone else. If you had a full tool & die shop with equipment of sufficient accuracy, you could probably buy mikuni 'stock' needles and then machine them across their entire lengths to match his, but unless you were doing it in larger batches, it would be cost-unproductive (you could use that same time it would take you to measure & duplicate to earn an income with the tool & die shop that would more than pay for a full jetkit ordered from him).

Cheers,
=-= The CyberPoet

[slanteeeyes]

Yeah, I don't plan on setting up a tool & die shop anytime soon lol--Thanks cyber, you've been a great help.