Canadian Carbs Needle Slide Valve Sticking Open
Posted: Sat Aug 29, 2020 12:07 pm
I've been noticing on my carbs that I'm able to take my finger, slide the black needle slide valves open all the way, and often it will stick open. It's worse on some carb bodies compared to others. It's part 12 on this diagram: https://www.motorcyclespareparts.eu/en/ ... carburetor (Bike is a 1992 xj600s with Canadian carbs)
I've noticed previously that tightening down the brass acorn nut in the float bowl (part 16) will often make it easier for the slide to get stuck. I believe this may be due to the pressure slightly warping the plastic slide block (part 17). I'm not completely sure that this is a huge problem when I'm actually riding the bike, as the slide will really only become stuck after a near full throttle, and even then the vibration may knock it loose or it may slide back into position after I get the bike home and take off all of the parts required to see the slides.
What I have noticed though is that once the bike is running warm (After about 20-30 of riding), taking off from stops in first gear often has the bike seem to bog down for a second before the power finally kicks in. What I'm hypothesizing is that the needle valve has gotten stuck open, and for that few moments the bike is running rich as fuel pours out from an entirely open needle valve.
I've thoroughly cleaned all of my carbs, especially around the slides. I have vacuum that does properly work all of my valve slides. I've got 100 main jets, 15 pilot jets, and I've moved my needle ring to the second position from the edge of the needle so that it runs just slightly leaner if that helps out with diagnostics. All of my slides and slide blocks seem to be in pretty decent shape.
So far I've found nothing online or anyone else having these issues, especially because the canadian carb slides are this weird non-cylinder shape. Any help would be extremely appreciated! I'd like to sell the bike soon but want to make sure that it's in top condition before I do so. Thanks!
I've noticed previously that tightening down the brass acorn nut in the float bowl (part 16) will often make it easier for the slide to get stuck. I believe this may be due to the pressure slightly warping the plastic slide block (part 17). I'm not completely sure that this is a huge problem when I'm actually riding the bike, as the slide will really only become stuck after a near full throttle, and even then the vibration may knock it loose or it may slide back into position after I get the bike home and take off all of the parts required to see the slides.
What I have noticed though is that once the bike is running warm (After about 20-30 of riding), taking off from stops in first gear often has the bike seem to bog down for a second before the power finally kicks in. What I'm hypothesizing is that the needle valve has gotten stuck open, and for that few moments the bike is running rich as fuel pours out from an entirely open needle valve.
I've thoroughly cleaned all of my carbs, especially around the slides. I have vacuum that does properly work all of my valve slides. I've got 100 main jets, 15 pilot jets, and I've moved my needle ring to the second position from the edge of the needle so that it runs just slightly leaner if that helps out with diagnostics. All of my slides and slide blocks seem to be in pretty decent shape.
So far I've found nothing online or anyone else having these issues, especially because the canadian carb slides are this weird non-cylinder shape. Any help would be extremely appreciated! I'd like to sell the bike soon but want to make sure that it's in top condition before I do so. Thanks!