My engine keeps producing this whiteish smoke

[Molino]

Hey guys. Last summer I had my GS550 running, it was a bit rough, but ran none the less. Now this summer I've went to tinker around with it and it's not running like it used to. From what I can tell, either two cylinders arn't firing (but they look like they're cranking, the valves are moving), or one cylinder isn't firing. If I try to run the bike every time it makes its 4th stroke I can see puffs of sort of white smoke come out of 3 of the exhaust ports. When I have the pipes on and I try to have it idle, I get this loud screech/pop from one of the pipes (2-1 exhausts), every compression stroke.

I'm almost baffled, (I came from working on 2 strokes, valves are new to me) I hope the engine didn't kick the bucket on me. Anyone know what could be happening here?

 

[BassCliff]

Hi,

What maintenance have you performed on the bike? There are two lists HERE. Have you done all of them?

Required maintenance:

***********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.

Carburetor maintenance:

Replace the intake boot o-rings, and possibly the intake boots. Here's the procedure:
http://bwringer.com/gs/intakeorings.html
Here's an overview of what happens with this particular problem:
http://cycleorings.com/intake.html
You'll also want to examine the boots between the carbs and the airbox. There's a good chance these are OK, but check them over.
And finally, if things still aren't exactly right, you'll want to order a set of o-rings for BS carbs from the GS owner's best friend, Robert Barr:
http://cycleorings.com
Once you receive these rare rings of delight, then you'll want to thoroughly clean and rebuild your carburetors. Here are step-by-step instructions that make this simple:
http://thegsresources.com/gs_carbrebuild.htm (for CV carbs)
Or for VM carbs: http://www.thegsresources.com/files/vm_carb_rebuild.pdf
*******************************

If you go through these lists completely and do the work properly, you are almost guaranteed to have a great running machine. If you take any shortcuts, skip any steps, or do incomplete work, you will be frustrated. You have a 30 year old motorcycle that probably needs 20 years worth of maintenance.



Thank you for your indulgence,

BassCliff

 

[Guest]

If I try to run the bike every time it makes its 4th stroke I can see puffs of sort of white smoke come out of 3 of the exhaust ports. When I have the pipes on

I don't know of a better way to destroy your valves, don't ever run it without the headers. Cold air (relatively) and hot valves don't mix.

 

[Molino]

So you think the valves are messed up on those two cylinders? I didn't run it like that, just cranked it over to make sure they were moving.

I did the carb maintenance and replaced the plugs last summer. I don't think it's a carb issue unless the two cyl arnt getting any fuel and that's why they're not firing. I think an engine issue so I figured I'd ask here because y'all have heard it all before

 

[Guest]

I haven't seen it. From what you said it sounded like you were running it without the headers. If not "never mind", but that would be a good way to damage it if you had. I would do a valve adjustment if you haven't done that yet, before doing anything else. Then run a compression check. If that is within specks, than you will know something about your piston rings and valve condition. Then you can go on to the rest of the required maintenance, O-rings, boots, carbs, electrical system. All that dull stuff has to be done before the fun stuff can happen.