.png "Powered by vBulletin")
update ...
we *think* we solved it. the boot from the air box to carb #3 was pushed in/folded slightly, like a grommet that's about to pop out. it wasn't obvious but when we got good light in between the carbs and the engine we could see a gap. well, not a gap, but it didn't look exactly like carb #2.
pulled them, double checked that the butterfly valves are sealing and everything else looks right, and put it back together. much better, but still rough and hesitating. sprayed some starting fluid up around each boot in turn, and still some increased rpm when the ether got in around the edge of boot 3.
pulled them apart again, pulled the boot out, and no apparent tears or problems. put the boot back in rotated so what was the bottom is now the top (even though its symmetrical, unlike the boots for 1 and 4) and tried a slightly different approach to putting the carbs back in.
short version: lightly secure the air box to the frame, fully seat the carbs on the air box boots, tighten clamps, carefully seat carbs into intake boots, tighten clamps, and THEN tighten the air box to the frame.
in any case ... it runs better, no variance in RPMs when sprayed with ether, and the idle adjust screw actually adjusts the idle.
it's been raining for three days, so no test ride ... but it looks promising at this point.
tl;dr too much air into carb thanks to poor installation
we *think* we solved it. the boot from the air box to carb #3 was pushed in/folded slightly, like a grommet that's about to pop out. it wasn't obvious but when we got good light in between the carbs and the engine we could see a gap. well, not a gap, but it didn't look exactly like carb #2.
pulled them, double checked that the butterfly valves are sealing and everything else looks right, and put it back together. much better, but still rough and hesitating. sprayed some starting fluid up around each boot in turn, and still some increased rpm when the ether got in around the edge of boot 3.
pulled them apart again, pulled the boot out, and no apparent tears or problems. put the boot back in rotated so what was the bottom is now the top (even though its symmetrical, unlike the boots for 1 and 4) and tried a slightly different approach to putting the carbs back in.
short version: lightly secure the air box to the frame, fully seat the carbs on the air box boots, tighten clamps, carefully seat carbs into intake boots, tighten clamps, and THEN tighten the air box to the frame.
in any case ... it runs better, no variance in RPMs when sprayed with ether, and the idle adjust screw actually adjusts the idle.
it's been raining for three days, so no test ride ... but it looks promising at this point.
tl;dr too much air into carb thanks to poor installation
Comment