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(Moved from Discussion... not sure if this is a carb/fuel question, or electrical/ignition, so flipping a coin...)
After letting my 1980 GS1000G sit, partially disassembled, in my garage for the past year (I know... bad owner), I've been putting her back together, but am running into a problem with the left pair of cylinders not firing.
Last year, I did a valve adjustment and carb teardown, with carbs fully disassembled, dipped, and cleaned (#1 had been clogged up due to tank rust), new (oiled) filter, new set of o-rings, new fuel/air lines, and resealed the airbox. The airbox boots were pretty new (still soft and flexible), but I added new boots/pipes between the carbs and engine. When I reassembled it all last year, I couldn't get her running, which I assumed at the time was because, like an idiot, I hadn't dealt with the tank rust.
This month, I pulled the carbs again, stripped and re-cleaned them following the guides (though they were still clean), did a bench sync and reassembled it, and set all 4 adjustment screws to 2.5 turns from the bottom. My next step was going to be to try out my new carbtune, using a clean coolant reservoir for fuel. After plugging the vacuum line to #2 (per the carb balancing instructions), it started up with minimal choke. It ran at a pretty high idle (1500-2000 or so) with the throttle released, but the RPM fluctuated (loping and racing) so much that I couldn't dial the idle back to normal or else it would stall.
After I let it warm up (with a fan on), the headers for #3 and 4 were hot (they tested around 190F), while those for 1&2 are cool to the touch (around 85). I checked the #1 float drain, there was fuel. I checked spark plugs and gaps (1 & 2 were wet), and pulled the plugs to visually confirm spark off of all 4 leads (which are pretty new NGK). I confirmed that the leads to 1 & 2 do not share the same coil. Battery is brand new, and had a full charge when I started testing. Tried again, but headers for 1&2 still were cool. I tried fiddling with the air adjustment screws - tweaking 1 and 2 had no affect on the RPM (not surprising, if they're not firing). I also checked compression (cold though), which seems to be within spec (120-140).
One thing I neglected to do this time was measure the float heights, but when I did it last year they were all spot on, no adjustment was needed. I suppose they could both be off now for some reason, but but before I pull it all apart again to check, I'm hoping y'all might be able to point me to something else that I might have overlooked and/or screwed up.
Thanks!
Chris
After letting my 1980 GS1000G sit, partially disassembled, in my garage for the past year (I know... bad owner), I've been putting her back together, but am running into a problem with the left pair of cylinders not firing.
Last year, I did a valve adjustment and carb teardown, with carbs fully disassembled, dipped, and cleaned (#1 had been clogged up due to tank rust), new (oiled) filter, new set of o-rings, new fuel/air lines, and resealed the airbox. The airbox boots were pretty new (still soft and flexible), but I added new boots/pipes between the carbs and engine. When I reassembled it all last year, I couldn't get her running, which I assumed at the time was because, like an idiot, I hadn't dealt with the tank rust.
This month, I pulled the carbs again, stripped and re-cleaned them following the guides (though they were still clean), did a bench sync and reassembled it, and set all 4 adjustment screws to 2.5 turns from the bottom. My next step was going to be to try out my new carbtune, using a clean coolant reservoir for fuel. After plugging the vacuum line to #2 (per the carb balancing instructions), it started up with minimal choke. It ran at a pretty high idle (1500-2000 or so) with the throttle released, but the RPM fluctuated (loping and racing) so much that I couldn't dial the idle back to normal or else it would stall.
After I let it warm up (with a fan on), the headers for #3 and 4 were hot (they tested around 190F), while those for 1&2 are cool to the touch (around 85). I checked the #1 float drain, there was fuel. I checked spark plugs and gaps (1 & 2 were wet), and pulled the plugs to visually confirm spark off of all 4 leads (which are pretty new NGK). I confirmed that the leads to 1 & 2 do not share the same coil. Battery is brand new, and had a full charge when I started testing. Tried again, but headers for 1&2 still were cool. I tried fiddling with the air adjustment screws - tweaking 1 and 2 had no affect on the RPM (not surprising, if they're not firing). I also checked compression (cold though), which seems to be within spec (120-140).
One thing I neglected to do this time was measure the float heights, but when I did it last year they were all spot on, no adjustment was needed. I suppose they could both be off now for some reason, but but before I pull it all apart again to check, I'm hoping y'all might be able to point me to something else that I might have overlooked and/or screwed up.
Thanks!
Chris
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