Well I've managed to an HRC MC28 hrc jet kit via various auctions. I picked up some jha kit AS25A needles too.

Before setting out to do the install, i have a few questions, I've searched the forum and haven't found answers to these.

Q1
I've noticed the jetting section provides base clip positions for the mc21 kit but provides numbers with several significant digits. Is it safe these are mm down from the top of the needle? I've also noticed that both the hrc and jha needles are quite a bit fatter, hence leaner, then the stock needles. All I'm really trying to do is remove the flat spot. Any comments on the difference in the needles is appreciated. ( stock vs hrc )

Q2
The needles appear to be the same length as the stock. Since i mainly sourced the kit from parts, does the mc28 kit require the longer main jet holder?

Q3
I'm running 155 mains in front and rear, so far bike runs great when I'm on the main jet so I'm inclined to leave them alone. Is there any reason to make the rear one size smaller or front one size bigger? I guess a plug chop would answer that...!

Q4
I'm a fan of making one change at a time. What effects do the y and x pieces have on jetting? Obviously they are the easiest to install. I'm okay dropping all the parts in at once, but would like to understand their influences.

Q5
I haven't plugged the pilot jets. I thought i read someplace that the mc28 didn't have them, but info seems conflicting. I confess when i rebuilt the carbs the first time they didn't stand out. If they do exist, I'm open to plugging them, will that drive me to a bigger or smaller main jet?

Like I mentioned above, I'm only trying to clean up a flat spot that is around 1/3 throttle. Other than that its spot on. But i also realize that what fixes the flat spot mat drive me to change some other settings to get it back right.