81-550T, R/R tested good, but…

[bwringer]

But, one last question please: That 3rd yellow stator wire connects to a W/G wire running to the headlight switch.
I should disconnect that yellow and connect it to what color wire in order for it to run into the R/R?
Thanks! Bill

The white/red wire.

[Buffalo Bill]

Just tried that, thanks…

Thanks Brian,
I just came in from the garage and tried that, and ran the engine too.
I had a look at the wiring diagram and came up with the W/R wire, but is it really that simple?
I ran the bike up the highway and back, pulled up to my garage and the bike held a fast idle then came down to 1100-1500 rpm. There still is a load when the headlight is on and the idle slows, but I take that for normal.

It all gets back to this bike's frustrating problem: after it's well warmed up from some riding, it won't hold an idle below 2200rpm with out stalling out.
By trying to fix this problem, I've really improved every other aspect of it's running, but it just won't fix.
Things I've done:
Tried the coil mod trick (bummer, returned it back again).
Replaced the coils with some from a 97 Bandit 1200.
Replaced the piston rings.
Changed out the main jets for some slightly bigger ones, (makes great top end power now).
Changed the pilot jets with some slightly larger.
Replaced all the intake pipes.
New battery.
Replaced the plugs.

[Nessism]

Wonder if it's sucking false air past the throttle butterfly valve shafts? Something is wrong if it won't idle properly.

Where are the pilot/mixture screws set and have you vacuum synced the carbs? My old 550T was dead stock and the idle would hang until the pilot/mixture screws were opened up to 3.5 turns.

[Buffalo Bill]

Ed…???

Ed, you're one of the few 550 owners who respond to questions, could your references please be specific: “the idle would hang”. What do you mean?
Thanks. Bill

[Nessism]

Ed, you're one of the few 550 owners who respond to questions, could your references please be specific: “the idle would hang”. What do you mean?
Thanks. Bill

After the engine is warmed up, the idle would not drop down to the normal 1100 rpm level, or only would do so slowly. Basically, the idle would "hang" at 2000 rpm or so and not consistently move lower. This is typically a sign that the engine is drawing false air but my old 550T did this with the mixture screws in further than 3.5 turns.

[Buffalo Bill]

Thanks, that's useful…

The Hanging idle concept could be correct, because as a reaction I can unscrew the fast idle screw until it reaches an exact point, then it just plummets down from 2200 and dies. This only happens after the engine is completely warmed up by riding.
I was suspecting things like the base of the vacuum tube for the petcock on the #2 carb. The valve ends could be letting air in too.
Thanks. Bill
P.S. I think this was my 1000-th post!

[tom203]

Your first post said that idle was ok with headlight off- which implied an electrical problem; maybe bad connection in headlight circuit or a r/r that doesn't deliver at low rpms dropping system voltage. That stator loop to left hand switch is useless IF you run with your headlight on- you're better off just sending stator output to r/r. But the r/r has to be working at 1500 rpm as well as 4000. A faulty r/r could deliver 15 volts at 4k thanks to higher frequency, but fall way off at low rpms.
On my bike, when I bypassed that loop ( and cleaned connections), my output went from 12.3 v ( nothing) to about 12.8 v ( something) at 2000 rpm. I'm still using the original r/r and I check it over the rpm range to ensure it's behaving. IF you notice excessive loading at idle, I'd suspect a poor r/r, especially since your battery is fairly new.

[Buffalo Bill]

Thanks…

Thanks Tom.
I'll check out the charging volts again, now that I've bypassed the headlight loop. However I'm using a cheap analog multitester, not accurate to .1 volts.
Bill

[Redman]

Bill,

15volts should charge the battery just fine, I have gone years and years with less than 14 (better now).

You measuring that at the battery?
Or at the R/R?
If measuring at the R/R, it is possible to be loosing several tents or more along the way to the battery, if any bad connections. Is real easy for a bad connection to be loosing a volt and a half or so, and that volt and a half make it so batteryt really isnt being charged well and make it seem like it is loosing charge over time when really it just wasnt charged that well to start with.

Stator papers have you measure for any voltage drop beteen batt+ and RR hot, and then also between batt- and RR-. And you can do that with your analog meter. I often use my 18 dollar radio shack analog meter rather than going and getting my better digital meter from my work tool kit.

Dave

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