82 GS650 Idle/Electrical issue

[MrSark]

I picked up a GS650 that was sitting around for a couple of years, and was intermittently started during that time. Took as much of the old gas out of the tank as I could and did a full tear down and rebuild of the carbs (used the kits from one of the popular supplier sites to replace the jets and gaskets). Put the bike back together, filled the tank with good fresh gas, replaced the plugs--they were fouled from the previous owner force feeding fuel to make the bike run--and after a little bit of a stern talking to it started right up on full choke and idled fine @ 3k RPM.

I gradually took the choke off and got the bike to idle at about 1500 RPM. It would idle for a few minutes and then slowly die. If the bike was about to stall I could tap on the throttle and it would idle again but then shortly after it would die. During this time it wouldn't race at all. I was unsure if the petcock was broken so during this time I left it on Prime.

Anxious to get out and ride a little, I took the bike for a quick 2.5 mile test ride around the block (city driving--petcock in the ON position). At the first stop light about a half mile down the street the bike idled at 3000 RPM, and subsequent lights I would have to open the throttle a little to keep it going. During the ride the bike was very smooth with no noticeable flat spots, engine racing, or hesitation. Once I got back, the engine stalled, and there was no juice left in the battery to restart the bike.

From searching around I am thinking my next steps are to do a test of the stator/rectifier for the battery problem. As for the idle issue, I am thinking my next steps are to check for intake leaks on the intake side of the carbs, and possibly replace the O-rings. The only difference that I see is that I am not having a high idle problem. It idles great with no choke for a few minutes and then dies. Once it dies the first time after taking the choke off it will not idle properly again unless I tap the throttle to keep it going. Also some suggestions I read were to do a compression test as well. Are there any other suggestions from riders with a similar problem? Thanks for the help.

1982 GS650G Shaft Drive
27k+ miles

[fgh]

You of course know that the stator will not produce enough current to run the bike at idle and has to use battery current to run. If your battery is weak the bike will stall. check the charging system as prescribed in the Stator Papers and repair as necessary. Let us know what's going on after you've eliminated electric supply from the equation.

[bakalorz]

You of course know that the stator will not produce enough current to run the bike at idle and has to use battery current to run. If your battery is weak the bike will stall. check the charging system as prescribed in the Stator Papers and repair as necessary. Let us know what's going on after you've eliminated electric supply from the equation.

Ummm no; sometimes at least, the bike will run with a totaly crap battery.

My 650's battery was pretty much shot when I bought it, a year later it was dead dead dead ... as in leave it on a charger for hours, and it still wouldn't even try to turn over. but after jumping it or push starting the bike would run fine.

and although my stator was fine, one of the bullet connectors was toast, so it was only running on 2 out of 3 phases (which kind of compensated for the fact that the regulator was toasted too)

All that said, he should fix the battery and/or charging system, but I suspect that is not the reason it won't keep running.

[duaneage]

I vote for O-rings on the intake boots. Maybe even the entire boots are bad and leaking, Could also be airbox problems. How are the rubbers for the airbox? There are many things on the intake side to check and if it has sat for a few years.

take a look at at the screen inside the tank on the petcock, it may be loaded up, and I would run a filter on the fuel line for a few weeks until it gets cleaned up.

[MrSark]

Thanks for the replies. The boots appear to be in decent shape, no cracking and not brittle. I used the WD-40 trick to get them pliable for the carb re-attachment and will WD-40/propane trick to test for leaks. The battery is new this season, and I have been reading the stator papers and will check the stator and rectifier next. Fuel flow is fine, and will take the screen suggestion under advisement. The tank is pretty full, so when I run it down I will take out the petcock and see if the screen is clear. Will let you know how it turns out.

[Nessism]

From my experience if the intake O-rings haven't been changed before you will be miles ahead by just do the job now - pay me now or pay me later.

Regarding the battery, if it's strong enough to turn the starter you are good as far as idles is concern. By all means check the stator and regulator/rectifier though and fix what needs fixing.

And by all means check the valves. Not likely to cause the problems you discribe but necessary none the less.

[MrSark]

After a couple of weekends of being busy, I was able to fault check the charging problem today. Once I took off the battery I saw that the negative lead from the RR was not connected anywhere (duh probably from when I was putting the airbox back on) but continued with the fault check for the stator and RR. The stator and RR check out, and the voltage I get at 5000 RPM is 13.3v. I ceaned the connections and the bolt in the battery case that holds the negative leads down in solvent and re-assembled.

I did an oil change today as well, and it looks like I have the problem with the oil pan threads being stripped. I saw there was a rubber stopper/wingnut device there but didn't realize why until I tried putting the new plug in. I will tend to that after the riding season when the bike is in storage where I can drop the pan.

It was a typical hot/humid day here, so I am going to take another test ride tomorrow--but it still starts right up with 3/4 choke and settles right down to idle when I take the choke off after a few minutes. I'll let you know how it turns out.