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Discussion Starter · #1 ·
Hi everyone, thanks in advance for reading this and offering advice if you can.

I bought an '82 GS650 about a month ago. Unless it's been sitting in the sun for a few hours (or has been running), it needs a dose of starting fluid before starting. Other than that, the bike was running fine.

Two weeks ago the bike started to bog down when I gave it gas. The sound would change, but no acceleration. I was doing 30-40 at the time. This lasted for a minute or so, not being able to accelerate, but then stopped just as suddenly as it started. For the next 5 minutes the bike ran fine. Then the bike started to bog down again, and as I pulled over the revs dropped all the way to 0 and the bike died. Switched petcock to RES and got the bike started, filled up with gas, and went home. The bike rode fine so I thought the bogging was just me running on fumes.

Took the bike out last week, ran fine for about 30 minutes. As I was pulling onto my street the bike started to bog down, same as before. No acceleration the whole way home (~1 min. ride). Next time I tried to start the bike, it dies whenever I close the choke. If I give it gas as I close the choke it'll stay running, but dies when I close the throttle.

Took out the carbs for cleaning, looked pristine (the guy I bought the bike from must've just cleaned 'em). Checked the fuel filter and fuel line, no problems there.

Any thoughts on what would cause a bike to bog down like that, or what I can do to try and fix it? I've read that too much gas will cause bogging, but it seems strange that the bike ran fine for weeks and then starts to bog down.

Gonna put the carbs back today (if it ever stops raining) and test the sparks, but other than that I'm at a loss.

Thanks again,
- James
 

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Adjust the carbs.
It could be a simple mixture adjustment, or you might need some different jets

If Im not mistaken I think that bike has anti-tamper caps on the mixture screws which will have to be removed before you can make adjustments.

Id do a plug chop though before making any adjustments. It could also be starving for fuel too, which is a lean condition.
If you get white plug on the chop its on the lean side,...with that in mind, there are a few things Id check before diving into the carb.

Tank cap vent clogged.
Fuel filter clogged
Kink or clogged fuel line
 

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Plug chop is a method of determining if the cylinder is running lean or rich.

You start off with some fresh clean spark plugs.
Run the bike up to cruising speed, pull in the clutch and hit the kill switch. You want the engine to go from cruising throttle to dead stop. Its ok if the bike coasts, but the engine must stop instantly for it to work.

Pull the plug. Look at the end of the spark plug.
The color tells you whats going on inside that cylinder

White = Lean
Light Brown = Normal
Dark muddy brown = Rich

you can also diagnose other problems as well. Such as burning oil, wrong octane gas causing carbon deposits, pre-ignition, etc.

Here is a link to photos of different plug chops to show you what to look for.

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html
 

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I guess you could, but I dont really like the thought of a bike at full throttle on the centerstand.

The easiest way is to take the old plugs with you. Put the new plugs in the bike, take off, get it up to speed, hit kill switch, pull over...take the plugs out, and put the old plugs back in...Ride home where you can inspect them at your leisure.

Here is a real good website with pretty much everything you need to know about tuning your carbs and the plug chop method.

http://www.justkdx.dirtrider.net/printcarbtuning.html
 

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Discussion Starter · #9 ·
That looks like a good article there.

I pulled the plugs but didn't see any sign of running rich or lean. The plugs looked like #14 or #19 from that first link you posted, so I don't think too rich/lean is the problem.

It finally stopped raining this weekend so I put the carbs back in. The bike started up ok :D and I let it warm up for a good long time before taking it for a spin, but it died as soon as I pulled out of the driveway (i think I ran out of gas). Yesterday I put gas in the tank, and again the bike started with no problems. Let 'er warm up and went for a few zips around the block with no problems. Problem solved.

Or so I thought. Got home from work today, eager to take a longer ride. Went around the block few times just to make sure things were OK, then headed out a bit farther. Just when I thought everything was fixed, bike started to sputter a bit and then died on me. Couldn't get it to start back up and ended up pushing the dang thing all the way home.

One thing I noticed while looking around the bike is that the two inside exhaust pipes have giant cracks in them, right before they join with the outside exhaust pipes and enter into the muffler. What kind of problems could a bad exhaust system have on performance? Would it cause bogging and/or dying like that?
 
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