Balky vacuum advance?

[Bonz]

Hey guys!

I posted a month or so ago about "clearing out the cobwebs" in my 80 1100 SG by running it hard up through the gears, and the bike runs smoother all around. However, I still have a flat spot that rears it's head, mostly as the bike is in the first 3-5 miles so I think it's just the bike needing to warm up.

But, when the power goes flat (very rarely, but it happens) after I have the bike well warmed up and many miles of riding, it makes me wonder if the vacuum advance is a bit sticky? I'll click down a gear, and the extra revs snap it out of the funk, then I shift back to the original gear I was in and it is fine.

I couldn't find any info by doing a search in regards to a sticky vacuum advance, but I may have missed something.

Thanks in "advance" for the thoughts.

[XSPastor]

Hmmm,

Have you checked your pick up coil wires lately? See this tech tip.

pick up coil wire fix

[thewiz]

"....I'll click down a gear, and the extra revs snap it out of the funk

What that might be doing is spoolin' up the centrifugal advance some and flingin' them tired ole, unlubricated weights out, thus advancing your timing ..... there seems to be inordinate amount of talk about timing, vac and centrifugal advances right now on this forum. Pretty easy to check the advances once you pull off timing cover.

I wonder if all the original centrifugal advance mechanisms are failing at once? ...arrrrgghhh ..... I too am having some of these issues.

[Bonz]

That's my thought. Not that they are failing outright, though possible. Just that they may get sticky over time and a need good looking at and cleaning/lubing/checking wires like you guys are all saying.

Leaving for vacation, have to get to it when I'm back in a week.

I'll keep you posted and thanks for the help.