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Hi all
I been looking around the forums trying to figure out where I should go from here. (I hope it doesn't involve a hand basket
).
A little bit of history, or just skip to the summary below.
I have an 82 GS850. I got it from my father in-law two years ago with 24,000 miles. All I did to get it running was to clean/rebuild the carbs and replace the foam air filter. I replaced all the jets with new ones from the kits. The bike ran well that summer (my first bike so what do I know
) and averaged around 44 mpg. Near the end of the riding season I took the bike to a recommended mechanic (that supposedly had a lot of experience on older bikes) for valve adjustment (now 28,000 miles). He said they were all WAY out of adjustment (may never have been done before), and the bike seemed to run better. I never winterized it because I started it up and ran it around every couple of weeks when the weather was decent. The next riding season (last Spring / Summer / Fall) I started noticing a drop off in mileage gradually falling to the low 30s, and popping (backfiring?) coming from the mufflers.
During this time I cleaned the air filter (I had put too much oil in it previously). Pulled the carbs and cleaned them (didn't tear them down completely just dissembled the upper and lower parts and sprayed carb cleaner through all the jets). Overall the carbs looked clean and didn't see anything obvious. I also did a bench sync on the carbs and verified with a kit-bashed manometer, and everything looked pretty balanced per the repair manual. At 36,000 miles I got brave and decided I was going to shim the valves myself (thanks to everyone here, the cable tie trick worked great). They were all way too loose. I'm not sure if the mechanic just guessed what it needed or if they changed that much. I got them all back int spec but still no improvement in mileage, however the popping diminished but didn't entirely go away. I also did the coil relay mod at this time. Riding partners were saying they could smell raw gas when following me, I could also smell it when I was stopped at traffic lights. At this point I decided to not mess with much since the weather was getting colder and I didn't want to mess something up since I was still riding it when ever the weather was nice.
I found that #2 spark plug was fouled, and replaced it and it quickly fouled again (within 300 miles). I've played with the air flow screw on the carbs trying to lean it out without any luck. I have torn down Carb #2 and it looked clean (I did clean it again just to be sure). I have just done a compression test and #2 was about 100 and the other cylinders were at 120. I put a little oil in the cylinder and it jumped to 120. All the plugs seem to have the same strength of spark (calibrated eyeball), however not what I would call strong.
In summary:
1982 GS 850
Stock airbox and pipes.
Was getting 44 mpg two years ago now getting about 30.
Raw gas smell while running (no sign of gas dripping anywhere)
#2 spark plug fouls quickly.
What I've messed with:
Cleaned the carbs (they looked pretty clean already).
Benched sync the carbs
Cleaned out the air filter (had too much oil originally)
Shimmed the valves within 2,000 miles
Installed the coil relay mod
Where to go from here.
After reading various threads on this site I'm leaning toward a ring job, but not looking forward to that major of a job. I've read the GS Greeting page and will look at the intake boots because I've noticed the idle speed varies, but I don't think this is the culprit.
If anyone has any other advice or ideas please let me know.
Thanks
I been looking around the forums trying to figure out where I should go from here. (I hope it doesn't involve a hand basket
).A little bit of history, or just skip to the summary below.
I have an 82 GS850. I got it from my father in-law two years ago with 24,000 miles. All I did to get it running was to clean/rebuild the carbs and replace the foam air filter. I replaced all the jets with new ones from the kits. The bike ran well that summer (my first bike so what do I know
) and averaged around 44 mpg. Near the end of the riding season I took the bike to a recommended mechanic (that supposedly had a lot of experience on older bikes) for valve adjustment (now 28,000 miles). He said they were all WAY out of adjustment (may never have been done before), and the bike seemed to run better. I never winterized it because I started it up and ran it around every couple of weeks when the weather was decent. The next riding season (last Spring / Summer / Fall) I started noticing a drop off in mileage gradually falling to the low 30s, and popping (backfiring?) coming from the mufflers. During this time I cleaned the air filter (I had put too much oil in it previously). Pulled the carbs and cleaned them (didn't tear them down completely just dissembled the upper and lower parts and sprayed carb cleaner through all the jets). Overall the carbs looked clean and didn't see anything obvious. I also did a bench sync on the carbs and verified with a kit-bashed manometer, and everything looked pretty balanced per the repair manual. At 36,000 miles I got brave and decided I was going to shim the valves myself (thanks to everyone here, the cable tie trick worked great). They were all way too loose. I'm not sure if the mechanic just guessed what it needed or if they changed that much. I got them all back int spec but still no improvement in mileage, however the popping diminished but didn't entirely go away. I also did the coil relay mod at this time. Riding partners were saying they could smell raw gas when following me, I could also smell it when I was stopped at traffic lights. At this point I decided to not mess with much since the weather was getting colder and I didn't want to mess something up since I was still riding it when ever the weather was nice.
I found that #2 spark plug was fouled, and replaced it and it quickly fouled again (within 300 miles). I've played with the air flow screw on the carbs trying to lean it out without any luck. I have torn down Carb #2 and it looked clean (I did clean it again just to be sure). I have just done a compression test and #2 was about 100 and the other cylinders were at 120. I put a little oil in the cylinder and it jumped to 120. All the plugs seem to have the same strength of spark (calibrated eyeball), however not what I would call strong.
In summary:
1982 GS 850
Stock airbox and pipes.
Was getting 44 mpg two years ago now getting about 30.
Raw gas smell while running (no sign of gas dripping anywhere)
#2 spark plug fouls quickly.
What I've messed with:
Cleaned the carbs (they looked pretty clean already).
Benched sync the carbs
Cleaned out the air filter (had too much oil originally)
Shimmed the valves within 2,000 miles
Installed the coil relay mod
Where to go from here.
After reading various threads on this site I'm leaning toward a ring job, but not looking forward to that major of a job. I've read the GS Greeting page and will look at the intake boots because I've noticed the idle speed varies, but I don't think this is the culprit.
If anyone has any other advice or ideas please let me know.
Thanks
). No sign of any gas smell or back firing and a lot more power than before.
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