Just Cleaned Carbs First Time, Now Having Trouble Starting the Bike
Posted: Sun Jan 14, 2018 9:56 pm
Hello Everyone, first post! Been enjoying lurking around the forum so far (so awesome there is a cb650 forum!) and see I have a pretty common complaint but I have some specific questions about my situation hopefully you could help me with.
I have an 81 cb650c I've been riding around for about 3k miles to its current 21k. It's been running okay (loves the choke) but is a bit weak until 2.5k rpm. I figured it's an old bike and the first owner let it sit for 9 years so I'd try to clean the carburetors.
I got them off yesterday, opened them up (but kept them together), cleaned out the main jets, saw they were 120s (bigger than stock I think) and the float needles looked new so I'm guessing some work had been already done on them. Besides some gunk on the slide bores everything was looking pretty good.
Get to carb 3 though where the fuel accelerator pump is adjoined and find the o-ring sitting there was disintegrated, held together with some kind of yellow sealant. Also the boot for the diaphragm rod fell apart basically as soon as I touched it. Without replacement parts on hand I ended up putting it back together without the o-ring or the boot, figuring they weren't doing much before in the shape they were.
I now think this may be why I can't the bike to start. I turned it over until the battery died, then got a jumper and turned it over some more. I opened the release valve on bottom of the bowls to find just a smidgen of gas in carb 1, the others dry. I suppose this means that o-ring I removed was really critical? What do you think? Any other checks I should do? There is also the vacuum stop between the tank and the carb, I don't know how to check if fuel is flowing through this but it was pristine inside. Fuel seems to leave the tank just fine until then.
By the way, even at full tightness, the boots from the airbox don't make a good seal against the carburetors. Should I be worried about this?
Thanks!
I have an 81 cb650c I've been riding around for about 3k miles to its current 21k. It's been running okay (loves the choke) but is a bit weak until 2.5k rpm. I figured it's an old bike and the first owner let it sit for 9 years so I'd try to clean the carburetors.
I got them off yesterday, opened them up (but kept them together), cleaned out the main jets, saw they were 120s (bigger than stock I think) and the float needles looked new so I'm guessing some work had been already done on them. Besides some gunk on the slide bores everything was looking pretty good.
Get to carb 3 though where the fuel accelerator pump is adjoined and find the o-ring sitting there was disintegrated, held together with some kind of yellow sealant. Also the boot for the diaphragm rod fell apart basically as soon as I touched it. Without replacement parts on hand I ended up putting it back together without the o-ring or the boot, figuring they weren't doing much before in the shape they were.
I now think this may be why I can't the bike to start. I turned it over until the battery died, then got a jumper and turned it over some more. I opened the release valve on bottom of the bowls to find just a smidgen of gas in carb 1, the others dry. I suppose this means that o-ring I removed was really critical? What do you think? Any other checks I should do? There is also the vacuum stop between the tank and the carb, I don't know how to check if fuel is flowing through this but it was pristine inside. Fuel seems to leave the tank just fine until then.
By the way, even at full tightness, the boots from the airbox don't make a good seal against the carburetors. Should I be worried about this?
Thanks!