1982 GS850g not starting

[sillymike]

Hi everyone:
just picked up a 1982 GS850g. The P.O. says it ran before, but i'm 90% sure this isn't the case since the spark plug wires were crossed and the throttle cable was hooked up to the choke.

the carbs were off, so I decided to rebuild them. Changed the oil, compression is good, new spark plugs.

I thought it would fire right up with some gas and the rebuilt carbs. I can get it to fire with starting fluid, but it won't stay going once the fluid burns off. I put fluid back near the intake, and it can fire. Runs for like 5-10 seconds this way.

Checked everything I could think of. There is definitely gas getting to the carbs, I made sure by checking the drain plugs. I thought maybe there might be small airleaks around the airbox boots, so I put gasket sealant around them just in case.

So, I'm stumped. It's almost like gas just can't come out of the carbs and into the combustion chamber, but I know all the passages are clear because I just rebuilt them.

I know it's fuel related because it fires with fluid. What's the next thing to check?

thanks so much!

[Nessism]

Did you follow the carb rebuild tutorial as linked on Basscliff's website (and my signature)? If not, that may be the problem.

[sillymike]

well... I didn't follow the guide while I was doing it, but I had a friend-of-a-friend there who is a motorcycle mechanic helping me.

I also just read the guide you suggested, and that's exactly what we did. Some things were different (i.e. used different methods of checking float height, etc) but everything was done.

Any other thoughts? And thanks for the reply!

[Steve]

Just checking on the details of the "rebuild".

How long did you soak the carbs?

If it wasn't at least overnight, you need to do it again.

.

[bwringer]

An 850 pretty much won't run without the airbox and filter in place.

Make sure the airbox sides are sealed (use foam weatherstripping) and that the filter isn't crumbling and is only lightly oiled. The air filter frame should be also be sealed to the airbox with foam weatherstripping.

It won't run right without the snorkel on the airbox, either.

You'll also need to check the valve clearances -- they get tighter over time, and this goofs up the vacuum in the carbs and the bike slowly gets harder and harder and harder to start. A lot of 850s got parked at around 10-15,000 miles because the owners were scared of checking valve clearances for some dumb reason, and the bike was getting too hard to start...

A properly tuned GS starts instantly, cold or hot. If it's not running before your thumb leaves the starter button, you have a problem.

Of course, intake boots covered in sealer are decidedly suboptimal... the sealer will deteriorate very quickly, so replace those ASAP. If they're still OK, replace the intake o-rings.

There's a list on Basscliff's site. Do that. All of it, every scrap.

[sillymike]

hi-
thanks for all the replies. I actually don't know what basscliff's website actually is, to get to the carb one i just followed the signature link.

Would you mind posting the website you are referring to?
thanks!

[Steve]

Here ya go, BassCliff's website.
.

[sillymike]

thanks! I'll check it out and get back to y'all

[subforry]

I think some of the carb rebuild guides have the initial setting of the butterflies open too far - the idle screw is in too far. At starting RPM, there will not be enough vacuum to pull in fuel if the butterflies are open too far.

Also I would not use starting fluid. If you must, use it very sparingly. It is very volatile and can cause damage to internal engine parts.

[BassCliff]

Greetings and Salutations!!

Hi Mr. sillymike,

You received your "mega-welcome" in THIS THREAD. I have repeated it here for your convenience.

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. You'll find all kinds of helpful tips, procedures, manuals, diagrams, "how-to" guides, etc, in the links below. Let's get started.

Let me dump a TON of information on you and share some GS lovin'.

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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please Click Here For Your Mega-Welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[bwringer]

I think some of the carb rebuild guides have the initial setting of the butterflies open too far - the idle screw is in too far. At starting RPM, there will not be enough vacuum to pull in fuel if the butterflies are open too far.

Also I would not use starting fluid. If you must, use it very sparingly. It is very volatile and can cause damage to internal engine parts.

Actually, it's best to just not use starting fluid at all. It's destructive, dangerous, stuff and there's nothing useful you can learn from it or accomplish with it.

Need to know if compression is OK? Use a compression tester. Need to know if you have spark? Pull a lead, insert a plug and check. Need to know if the timing is right? Look at the marks.

[sillymike]

Hi everyone:
I know this is an old thread at this point, but I just got through going through the carbs exactly as in the guide.
Didn't vacuum synch yet but did a visual bench synch (with the wire).

Still the same problems. Not starting, sounds like it wants to but just won't. Have spark, have compression, carbs are exactly as specified in the guide but with a visual synch. Should be good enough to get them running to do a vacuum synch, but nothing.

I'm stuck as to what to try next. I feel like it really is close, maybe even one of those situations where once I get it going it'll be easier and easier.

Thoughts? I'm working my way through all the info on basscliff's webpage but I'm more than open to advice in the meantime.
thanks in advance!

[BassCliff]

Hi,

Yes, the carbs do not have to be vaccum sync'd to get the engine to run. They just have to be close (bench sync). Ensure that the carbs have been completely disassembled, cleaned (dipped), and properly reassembled with a new O-ring kit. DO NOT use aftermarket "carb rebuild" kits.

Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

And:


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

Did you put the airbox back on? Is it properly sealed? Is the whole air intake system properly sealed? New intake boots and O-rings? New carb boots? A clean, lightly oiled air filter?


Thank you for your indulgence,

BassCliff

[Steve]

Where are you? Maybe one of us is close enough to help you in person.

.

[bwringer]

Possibly a dumb question: what order are the spark plug leads in?

One coil (usually the left coil) fires 1 and 4 (the outer two cylinders), and the other coil fires 2 and 3 (the inner cylinders).

It's VERRRRRRY common to find this goofed up if you or the PO are used to four cylinder car engines.

Also, check the voltage at the coil.

And I hope you've tossed that damn starting fluid in the trash, too.