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Carbs keep flooding into main throat.
- Thread starter CaseySmithersxs
- Start date
.... Yes, especially then!
CaseySmithersxs
XS650 Junkie
Okay guys, my carbs aren't leaking anywhere NEAR like 6x5s0 are. Mines just a very slow gradual leak... I guess the new orings didnt fix the problem.... Looks like in back to square one. And I'm almost positive my carbs only have that one link tube at the bottom, and not that other one over the vents.
Definitely a mystery.
Not sure if this was done or not, this got confusing real quick, but here's what lets the fuel level equalize in the carbs:
It's the vents that let fuel rise in the bowls. Normally them being clogged would cause fuel starvation and levels always too low. But you never know...
These are 78+ BS38s, I think on the pre-78 the vents are here:
BTW compressed air would likely not be enough to completely unclog, varnish does not just get blown out usually some solvent is needed (carb cleaner, mineral spirits etc.)
HTH
Not sure if this was done or not, this got confusing real quick, but here's what lets the fuel level equalize in the carbs:
It's the vents that let fuel rise in the bowls. Normally them being clogged would cause fuel starvation and levels always too low. But you never know...
These are 78+ BS38s, I think on the pre-78 the vents are here:
BTW compressed air would likely not be enough to completely unclog, varnish does not just get blown out usually some solvent is needed (carb cleaner, mineral spirits etc.)
HTH
CaseySmithersxs
XS650 Junkie
I will deff try that man. Open for anything. Also my bike stumbles bad right off of idle in every gear, should I bump my needles up a notch?
CaseySmithersxs
XS650 Junkie
Haha true that.
o-ring was never the problem .................Fix one thing first. Start chasing abnother problem and you wont know what you are trying to fix.
CaseySmithersxs
XS650 Junkie
True that guys. Thanks for keeping me in line haha
stumble off idle is usually weak pilot circuit apparently . Try screwing the pilot screws out 1/2 turn at a time to max 4x turns . If no improvement you'll need to increase pilot jet size.
If you've ever used compressed air on assembled carbs, there's a chance that the brass floats collapsed (a little to a lot). If so, they won't float properly and you must use the 'clear tube method' to set floats.
CaseySmithersxs
XS650 Junkie
I've already set the floats with the clear tube method
have you given up casey ?
Have you checked both the diaphragms are seated correctly and sealing?
If you lift the slide to the top and put a finger over the slit at the top of the venturi to seal the vent ,the slide should stay up at the top.
If one or both slides start to fall slowly then you have a leak somewhere . It could either be the diaphragm holed or not aligned and seated properly.
Some techs recommend that the diaphragms should be bedded in a rubber sealant to ensure a good seal.
I've used a hi temp windscreen silicon on the carb stubs to make absolutely sure I didn't get any air leaks on the inlet side
Have you checked both the diaphragms are seated correctly and sealing?
If you lift the slide to the top and put a finger over the slit at the top of the venturi to seal the vent ,the slide should stay up at the top.
If one or both slides start to fall slowly then you have a leak somewhere . It could either be the diaphragm holed or not aligned and seated properly.
Some techs recommend that the diaphragms should be bedded in a rubber sealant to ensure a good seal.
I've used a hi temp windscreen silicon on the carb stubs to make absolutely sure I didn't get any air leaks on the inlet side
CaseySmithersxs
XS650 Junkie
Yea diaphragms are good, one problem i do still have is the carbs still slowly flooding when the bikes off, I've got the new o-rings on the needle jets and they have been on for over 2 weeks. I went in a 50 mile cruise, and they still slide right out(needle jet). Are they sopposed to do this? Or are they sopposed to be seated and hard to come out?
Your float valve(s) is(are) leaking, pure and simple.
CaseySmithersxs
XS650 Junkie
The valves and seats are new... From 650 central. And I cant get it to leak on the bench. But if I go for a ride then park the bike, boom. And it's not fast at all.
Any suggestion is answered with "i have done that" or "thats not the problem".
Can't help those that wont listen. Some time you have to go back and do things again and again and go over peoples answers. The problem has, (99.9%), probably been answered at least twice.
Don't have any more help for you on this, good luck and if you ever find out the problem post an answer.
Can't help those that wont listen. Some time you have to go back and do things again and again and go over peoples answers. The problem has, (99.9%), probably been answered at least twice.
Don't have any more help for you on this, good luck and if you ever find out the problem post an answer.
CaseySmithersxs
XS650 Junkie
10-4. Peace
Doesn't matter where you bought them, or how new they are, you have a leaking float valve(s).
Fail-safe way of bench testing float valves:
Carbs upside-down on bench. Float bowls removed. Fuel cross-over tube connecting the two carbs attached. Float valve seat gaskets (washers) installed, float valve seats screwed in tight. Float valve needle installed. Floats and hinges do NOT need to be installed.
Plug one fuel inlet.
Attach a piece of tube (18" is good) to the other fuel inlet. Put other end in your mouth, and suck until you get a good vacuum, then "hold" the vacuum with the tip of your tongue. Vacuum should hold "forever." If tube slips off of your tongue, you have a bad float valve. Remove the cross-over tube, plug the cross-over nipple, and repeat to discover which valve is bad (or both).
This is 100% reliable. If you don't discover a leaking float valve, I will give you my bike.
Fail-safe way of bench testing float valves:
Carbs upside-down on bench. Float bowls removed. Fuel cross-over tube connecting the two carbs attached. Float valve seat gaskets (washers) installed, float valve seats screwed in tight. Float valve needle installed. Floats and hinges do NOT need to be installed.
Plug one fuel inlet.
Attach a piece of tube (18" is good) to the other fuel inlet. Put other end in your mouth, and suck until you get a good vacuum, then "hold" the vacuum with the tip of your tongue. Vacuum should hold "forever." If tube slips off of your tongue, you have a bad float valve. Remove the cross-over tube, plug the cross-over nipple, and repeat to discover which valve is bad (or both).
This is 100% reliable. If you don't discover a leaking float valve, I will give you my bike.
Last edited:
ippytattoo
Just another grumpy old hack.
CaseySmithersxs
XS650 Junkie
Sorry spud, you owe me a bike? I'm telling my float valves are good. I've done everything you guys have said to do. My bad if it pisses yall off that nobody including myself can find the answer, but this is a f****** forum, could have sworn thats what these are for. Troubleshooting and sharing builds.
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