HRC F3 vs SS/SP Needles - Why are SS/SP Richer????

[999Gomerz]

KRC everyone,

I have written a few posts with questions and no one seems to answer them. Not sure why, but i'll try again.

If the root diaeter of the needles increases as the letters goes up, ie 8JF & 8JG are richer than 8ZH 8ZJ 8ZK.

ie the SS/SP are narrower than the F3 needles an thus the SS/SP would be richer.

Can anyone tell me why this is the case?? I thought the F3 ones would be richer cause more engine mods.

[cajun]

That would be an unknown here. HRC does things that only they know. BUT. What are you trying to accomplish?

[Cammo]

HRC does things that only they know.

Pretty much!!

If the root diaeter of the needles increases as the letters goes up, ie 8JF & 8JG are richer than 8ZH 8ZJ 8ZK.

This is not how they're classified. The diameters are listed in the parts description of the manuals, some of them are the same between the ss and f3 kits, though the taper on them is different to account for different fuelling requirements.

It looks as though honda made some progress on improving the fuelling between the 90 f3 and the 92 ss kits. Bigger pilot jets were offered in the later ss manual which add extra fuel to the whole rev range (not just one part as many believe). This covered up any minor glitches in the fuelling transitions by allowing you to use slightly leaner needles and main jets.

I usually found that the getting the needle fuelling spot on was the least most critical part of the hrc carb setup.

[Drunkn Munky]

Slight thread drift, of the 2 needles in the HRC kit 8ZF and 8ZG which is the leaner?

[lukemillar]

Slight thread drift, of the 2 needles in the HRC kit 8ZF and 8ZG which is the leaner?

Pretty sure that the 8ZG are leaner

[Cammo]

of the 2 needles in the HRC kit 8ZF and 8ZG which is the leaner?

Usually the thicker the needle the leaner it will be, however ideally you'd want to measure the diameter at various points on the taper as one could be richer than the other at particular points.

There's some needle measurements here, but no comparison of F and G:
viewtopic.php?f=24&t=17476&p=122008&hil ... le#p122008

Seat of the pants is just as good as any measurement I reckon when it comes to midrange fuelling!

[999Gomerz]

Thanks guys.

I was just trying to understand why maybe the SS/Sp were richer given less engine mods.

Cammo shed some logical light on the matter.

Cheers,