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Here’s the parts of the puzzle:
As bought from the PO, my 1980 GS850G had a V-H 4-1 exhaust, and non-K&N pod filters. It would fire up at a touch of the start button, needing only a little choke if it was cold. Idle was smooth, and acceleration was smooth and quick – but only up to about 5k rpm. Then it would flatten out, and could not be pushed beyond 5500 rpm at all.
From all my reading and research, certainly sounded like a carb setup issue. I have finally got a chance to tear into the carbs now, and here’s what I have found:
Carbs were fairly clean, with no evidence of plugged passages or crud. Carb #1 had that broken-and-glued float pin post, but I think that was working ok until I touched it during teardown. I also found the following deviations from stock:
Main jets - #140 (#115 is stock);
Pilot jets are #20 (#40 is stock)
Jet needles are NOT stock as they have the multiple clip positions and the clips are in the third slot from the top. MIGHT be Dynojet needles – setup is per Dynojet instructions?
“Air correctors” have been put in the passages, like what is described in the Dynojet Stage 3 instructions?
The replacement #1 carb I bought from another member here does NOT have the ‘air corrector’ installed – that was my first hint mine were different.
The slides lift holes have been drilled – again, like the Dynojet instructions. I know that because the drilling job was crappy. The lift hole looks ok from the bottom, but from inside, you can tell they weren’t careful. I don’t know if those oval holes will adversely affect performance.
So it looks like someone did a half-assed Dynojet conversion.
I was considering return to stock exhaust and air box (and have those parts), but with what I see in the carbs, I’m considering staying with the 4-1, getting K&N pods and getting the full Dynojet Stage 3 kit, because I can’t reverse the modifications to the slide lift holes, and the ‘air corrector’ inserts.
What say the carb gurus?
As bought from the PO, my 1980 GS850G had a V-H 4-1 exhaust, and non-K&N pod filters. It would fire up at a touch of the start button, needing only a little choke if it was cold. Idle was smooth, and acceleration was smooth and quick – but only up to about 5k rpm. Then it would flatten out, and could not be pushed beyond 5500 rpm at all.
From all my reading and research, certainly sounded like a carb setup issue. I have finally got a chance to tear into the carbs now, and here’s what I have found:
Carbs were fairly clean, with no evidence of plugged passages or crud. Carb #1 had that broken-and-glued float pin post, but I think that was working ok until I touched it during teardown. I also found the following deviations from stock:
Main jets - #140 (#115 is stock);
Pilot jets are #20 (#40 is stock)
Jet needles are NOT stock as they have the multiple clip positions and the clips are in the third slot from the top. MIGHT be Dynojet needles – setup is per Dynojet instructions?
“Air correctors” have been put in the passages, like what is described in the Dynojet Stage 3 instructions?
The replacement #1 carb I bought from another member here does NOT have the ‘air corrector’ installed – that was my first hint mine were different.
The slides lift holes have been drilled – again, like the Dynojet instructions. I know that because the drilling job was crappy. The lift hole looks ok from the bottom, but from inside, you can tell they weren’t careful. I don’t know if those oval holes will adversely affect performance.
So it looks like someone did a half-assed Dynojet conversion.
I was considering return to stock exhaust and air box (and have those parts), but with what I see in the carbs, I’m considering staying with the 4-1, getting K&N pods and getting the full Dynojet Stage 3 kit, because I can’t reverse the modifications to the slide lift holes, and the ‘air corrector’ inserts.
What say the carb gurus?
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