Use new clamps (or wider ones) on the carb boots to the head, too. They leak now, from being hard. This adds much roughness, and dark sparkplugs, and other such issues. You can also replace them: they cost about $80 per set, new from Honda.
You can also cut one spring at a time if you wish, which will make it like automotive distributors where the early advance is faster, the later slower.
Thanks Hondaman & others,
I took care of the boot issue earlier this summer. When I removed the old ones, I did find evidence of a small leak (a little staining) on #3 boot. All boots were hard but still pliable with a squeeze, no cracks, etc. Weird thing was, when I held the boots in hand and mounted one of the original 1974 clamps, I could pinch the clamp by hand and make the ends meet.. All those clamps "looked" fine (tangs not bent over from over tightening, etc.).
Replaced everything with a new set of Honda OEM intake and airbox boots. Also purchased a set of the new style Honda clamps (seem to recall the ones used on the VF750).
Also took any ignition issues out of the equation earlier this year. I thought I might have a weak spark at low rpm. When testing the coils, I couldn't get a consistent OHM check on one or two of the secondary leads so I bit the bullet and went the Dyna route (coils, CDI, & wires). Would have liked to have kept it stock but there wasn't much difference in price of a new Honda coil pack vs. the Dyna system.
All of theses repairs are an attempt to correct a rich running engine (from idle to about 4000 rpm, runs clean above that). It's been this way for a while now and I haven't been able to pinpoint the issue.
Research on this site and others recently lead me to checking my OEM needles and needle jets.
This also made good sense to me. I've tried many things but I've never been able to take the "Blurble or Hesistation" out of this bike from idle to 3500 - 4000 rpm. Never really needed choke to start and the issue became more pronounced as the bike warmed up.
Never made sense to me that the main or pilot jets could "wear out" just by gas passing through them. All my jets are original OEM's and look to be in good shape.
The needle and needle jet do rub against each other, that they could wear made sense.
What I'm assuming now is that an excessive about of gas may have been coming through the needle jet when the needle is lowered in the hole (i.e. idle to 1/4 "ish" throttle). Gas flow through the needle jet at low throttle settings should be minimal if any. The side of the needle is flat in that range and the taper doesn't come into play until the throttle is opened more.
I removed all the needles from the slides and the needle jets from the carbs. Then performed a "wiggle" test of those two pieces in the area that looked shiny / grooved.
Seemed to me to be a fairly loose fit (some worse that others) so I bought 4 new Honda OEM needles and needle jet sets. I'm pretty sure this gamble is going to pay off. According to my "wiggle test", the new needle & jets are a much tighter fit.
Between this latest fix and the spark advance correction, I'm hoping to have this issue resolved.
Regards, Ken