Idle Adjust Question

[mak68]

Hello,
Let me start by saying that I've found this forum and many of the regulars' tips and advice to be a real big help to me, so a big thanks.

My issue is not so much a problem as it is more of a question. I'll first give a rundown of the particulars:
The bike is an '82 GS750T, all stock, in pretty decent condition appearance wise anyways. Had for 7 weeks and it's been running quite well afaik. This is what I've done to it so far:
1-Changed air filter and sealed the airbox/cover with weatherstrip.
2-Changed oil and filter (Castrol 4-stroke 10w40 and Wix filter)
3-New plugs (NGK D8EA gapped to .028")
4-Went over the stator papers and accordingly the electrical is healthy. Re-connected the R/R ground to the battery negative terminal. Went over every connection and ground I could get my hands on, ensured they were clean and greased 'em with dielectric grease.
5-Rebuilt the starter (part of what I do for a living), it seemed a bit slow. Good thing as the brushes were worn and the commutator needed a good cleaning.
6-Replaced the stock solenoid with a heavy duty Ford. I get them at cost, around $4.00 Can. So why not.
7-Did the coil relay mod. Definitely gave the bike more jam. Very nice tip.
8-Adjusted valve clearances. All 16 at .005".

Here's the thing, the last couple of days, it's idling rougher than I'm used to. While riding it also bogs/stutters once in awhile as it's warming up, I've noticed it mostly in 1rst, 2nd, 3rd gears. I've also noticed the engine lopes a little bit at stop lights (1rst gear, clutch lever pulled in).
Did the petcock vacuum tests according to here:
http://www.cycleorings.com/petcock.html
Petcock is healthy.

Plugs have soot, all 4. So I decided to do the "highest RPM idle adjust" from here:

http://members.dslextreme.com/users/bikecliff/images/highest_rpm_plug_chop.html

To be crystal clear, this is the screw I was adjusting:




Following the high idle procedure, step by step, by the time I got to adjusting carb #1, there was no difference in idle, no matter how many turns, clock or counterclock, the idle stayed the same, no bogging, no increased RPM, nothing. What I did afterwards was bottomed all four mixture screws, and brought them up 1.5 turns (lean the mix as I understand it). The idle is still rough, but no bogging or loping at stop, so far.

The next thing on the agenda is carb cleaning, and my guess is that the idle issue is related. I've already got four kits from Parts'n More in hand, and have the O-ring sets ordered from Robert Barr:
http://www.cycleorings.com/
(Great deal on those rings btw).
Plus a manometer and colortune on the way.
My mechanical background has been cars, and fuel injection, not so much carbs. But this no change in idle has been bugging me. Any ideas? Something I might have to worry about?
Input appreciated.

 

[doctorgonzo]

I've never had a lot of success with "highest rpm method" either. Same as you, can't get enough idle change. Lots of things COULD be going on, including dirty carbs. Sync has a big effect on idle as well. That carbtune may smooth it out quite a bit. I had a wandering idle until I did it. I'd try about 2 turns on the pilot and see if it has good or bad effect. I keep meaning to buy one of those Ford Solenoids.

 

[Steve]

I've already got four kits from Parts'n More in hand, and have the O-ring sets ordered from Robert Barr:

Keep the kits fro Parts'n More sealed, maybe you can sell them to someone else. Chances are that the o-rings from Robert Barr are all you will need inside the carbs.

When you get the carbs cleaned, finish up with a bench sync. When you get the carbs back on the bike, do a dynamic sync. That sounds to me like it might be your problem now, but no sense in doing it now if you are getting ready to dismantle the carbs for cleaning.

Yes, that is the correct screw to adjust for idle mixture. When you re-assemble your carbs after the cleaning, all the other screws and jets should be reasonbly snug. Your highlighted adjusters are the only ones that are to be left 'less-than-snug'. You indicate that the bike is all stock (airbox and exhaust system), so start with that screw somewhere between 1 1/2 and 2 turns out from lightly seated. That will be good enough to start the bike for further tuning.

.

 

[almarconi]

Keep at least one of the rebuild kits..never know when a part will fall down the sink, disappear in the grass or slide under a cabinet. If you ruin one of the screw heads trying to get the carb apart its nice to have a spare at hand.

 

[Guest]

thats an exhaustive list of things you've already done!
while the carbs are off, inspect the intake boots and the orings behind them and replace as necessary
a good carb clean is likely to solve your prob

 

[mak68]

Thanks for the carb rebuild tips and advice guys, appreciated.