Today 04:17 PM Dave8338 Is the bike stock (air box, filter, pipes)?
Have you completely torn down and soaked the carbs and replaced all the o-rings in them? Sounds like a lean condition.
I agree with Dave and here is some info from Bass Cliffs website on 850's. I am sure he will be along shortly for your "official" greeting.
***********Quoted from Mr. bwringer************
Every GS850 [and most other models] has (or had) a set of well-known issues that MUST be addressed before you have a solid baseline for further troubleshooting. It's a vintage bike, and it's quite common (as in, every single GS850 I have had contact with) that there are multiple problems that have crept up and slowly gotten worse over the years. It's not like a newer vehicle, where there's generally one problem at a time.
These common issues are:
1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.
What I have noticed at the rallies is that very, very few 850Gs are actually running right. Make VERY sure it's actually running the way it's supposed to before busting out the modifications.
Brian's E-Z and fun plan for GS850 happiness:
1) Seal the airbox and air filter with weatherstripping.
2) Ensure no intake leaks. Spraying WD-40 or water doesn't tell you much, since very small air leaks can cause problems even though they won't suck in enough WD-40 to make a difference. Replace your intake boot o-rings and boots if needed, and seriously consider spending the lousy $28 for new airbox/carb boots.
3) Ensure clean carbs with correct settings, new o-rings, and original OEM jets. No, not just squirted with something. I mean completely disassembled.
4) Check/adjust valve clearances (Manual calls for every 4,000 miles. This is not optional.)
5) Ensure healthy electrical system.
6) Seriously consider upgrading coils and plug wires.
7) Install new, stock NGK B8-ES plugs gapped to .031".
8 ) Fine-tune float height and idle mixture screw to ensure best off-idle transition.
9) Clean air filter and reinstall with only the lightest oil mist -- over-oiling and/or letting the filter get dirty is a common and critical mistake, and will make the bike run funny at low speeds and run rich. This may take a few tries.
10) Make sure the exhaust seals are sealing.
11) Ooh, much better now, huh? You're gonna need upgraded suspension - Progressive or better fork springs and shocks. Set suspension sag appropriately.
12) Upgrade brakes with new pads and stainless lines to deal with all that extra speed.
13) Install new petcock, since I'm going to head to the roof with a rifle if I have to read about yet another #2 plug fouling and failed hillbilly attempts to rebuild the petcock and/or deny there's a problem.
14) Oh yeah -- check compression somewhere in there to ensure the valves and rings are reasonably healthy.
15) You'll probably need new OEM clutch springs -- the clutches last forever, but the springs get tired after 20 years or so under pressure. E-Z and cheap.
