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A friend of mine has a '76 900ss (lucky b*stard) and it has run fine since he bought it, but last week it began coughing as thought the vertical cylinder was running lean, he limped it home and gave me a call.
I went to look at it tonight and fiddled with the carbs for about an hour before retiring home to think about the problem. Here goes, when you start the bike, you have to tickle the carbs and it runs fine (what sweet music thrugh the Conti megaphones) for about a minute, then the left tailpipe starts popping and eventually shoots flame before the bike dies. Tickle the carbs and it runs fine for about a minute. I took the carb off and checked the te floats for proper adjustment, all of the jets are clean, needle and seat are functioning properly, accelerator pump works, no air leaks between carb and cylinder head, reset the mixture screws to a baseline that matches the other carb (they weren't more than 1/4 turn different) and reasembled. Fired right u[ and ran beatifully for about a minute. tickled the carb with the engine running and it claered up for awhile and then went ti sh*t again. I rechecked that the floats were adjusted properly and not sticking, but it appears to not be getting any fuel into the bowl while running. The plugs appear to be burning about right, a little dark, but there is no load. BTW it has the 40mm Del'Ortos as factory for an Australian bike.
I went to look at it tonight and fiddled with the carbs for about an hour before retiring home to think about the problem. Here goes, when you start the bike, you have to tickle the carbs and it runs fine (what sweet music thrugh the Conti megaphones) for about a minute, then the left tailpipe starts popping and eventually shoots flame before the bike dies. Tickle the carbs and it runs fine for about a minute. I took the carb off and checked the te floats for proper adjustment, all of the jets are clean, needle and seat are functioning properly, accelerator pump works, no air leaks between carb and cylinder head, reset the mixture screws to a baseline that matches the other carb (they weren't more than 1/4 turn different) and reasembled. Fired right u[ and ran beatifully for about a minute. tickled the carb with the engine running and it claered up for awhile and then went ti sh*t again. I rechecked that the floats were adjusted properly and not sticking, but it appears to not be getting any fuel into the bowl while running. The plugs appear to be burning about right, a little dark, but there is no load. BTW it has the 40mm Del'Ortos as factory for an Australian bike.