richardthemotorcycle1
XS650 Guru
Hey guys just clean my carbs, started bike today and gas coming out right side air box, both floats were set the same, what could it be?
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Carbs, one side leaking gas
- Thread starter richardthemotorcycle1
- Start date
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- Tags
- carb advice needed
well I hate to say it but I can't see it being anything else but your float needle valve not shutting off for some reason. 
probably need to come off again.
I've got my carbs on the table in front of me as I type and the more I work on them the more I realise just how meticulous we need to be with these 40 year old carbs.
Did you measure both sides of each float ? these floats can get twisted and end up different heights at each end.
22mm+-1mm from the gasket surface with only the lightest pressure from the float weights. Best to lower them down gently onto the needles so that the needle springs do not get compressed and give a false reading.
The other suggestion I'd make is to gently operate each float at an angle to make sure nothing is binding with friction anywhere and make sure that the float Tab is horizontal with the floats inverted so no undue lateral pressure is placed on the float needles or they'l stick in the bores
good luck matey.
probably need to come off again.I've got my carbs on the table in front of me as I type and the more I work on them the more I realise just how meticulous we need to be with these 40 year old carbs.
Did you measure both sides of each float ? these floats can get twisted and end up different heights at each end.
22mm+-1mm from the gasket surface with only the lightest pressure from the float weights. Best to lower them down gently onto the needles so that the needle springs do not get compressed and give a false reading.
The other suggestion I'd make is to gently operate each float at an angle to make sure nothing is binding with friction anywhere and make sure that the float Tab is horizontal with the floats inverted so no undue lateral pressure is placed on the float needles or they'l stick in the bores
good luck matey.
Last edited:
richardthemotorcycle1
XS650 Guru
Thanks peanut, I take them back off and check it out.
Float spec for the '81 and newer BS34s is 22mm (± 1mm). Don't use 24mm, that's wrong. If you did use 24mm, you probably wouldn't have an over flow problem but rather a lean running problem. The fuel level in the bowl would be 2mm lower than it should be. I know that doesn't sound like much but when it comes to float settings, it is a lot.
richardthemotorcycle1
XS650 Guru
Hey 5twins, no I set them at 22mm, should I replace the float needle valve?
Apologies Richard I should have checked before offering advice .
Best listen to 5twins he's always right and he co-wrote the carb guide
richardthemotorcycle1
XS650 Guru
Hey guys, took carbs off again and adjusted the float, put back on and it's still leaking just the right side, the bike don't sound right when giving it throttle, almost like it has a air leak but I check and can't found any
richardthemotorcycle1
XS650 Guru
Hey guys, re-adjust the float, doesn't leak, re-clean carb, my question, when putting mixture screws back, should you take o ring off and washer and put them in first or can you leave on screw to put back in?
You can leave them on the screw, just get the sequence right. You want the little washer between the spring and the o-ring so the spring doesn't dig into and chew up the o-ring. The o-ring is at the bottom of the stack and seals into the bottom of the hole.
richardthemotorcycle1
XS650 Guru
Thanks 5twins, that how I did it and this time I made sure carb clean sprayed a out all by-pass holes and all the jets too and passages.
It is easier for me.to make the stack on the needle and turn the carbs upside down to insert.
richardthemotorcycle1
XS650 Guru
Thanks weekendrider.
richardthemotorcycle1
XS650 Guru
Trying out clean carb tonight, hopefully it well start, my question is with the new Danstall reverse cone mufflers have any affect on my air mixture setting? I'm 3 turns out.
richardthemotorcycle1
XS650 Guru
Hey guys cleaned my carbs and still no throttle, the only thing I didn't spray down through was the brass tubes, maybe they are clogged? What you think, I have a Manuel choke. I'm ready to scream
never had this much trouble with my carb off the 83 heritage special.
never had this much trouble with my carb off the 83 heritage special.
what do you mean by 'I have no throttle' ?
You need to be more specific if anyone is to help you. Remember we cannot see hear and test your bike we only have your description to go on.
Do you mean the throttle cable is stuck
or throttle valves do not open?
or when you open the throttle the engine does not respond ?
If the latter then you need to either state exactly which part of the throttle opening isn't responding correctly or post a video so we can see and hear the problem.
Each part of the throttle opening uses different jets and components
You need to be more specific if anyone is to help you. Remember we cannot see hear and test your bike we only have your description to go on.
Do you mean the throttle cable is stuck
or throttle valves do not open?
or when you open the throttle the engine does not respond ?
If the latter then you need to either state exactly which part of the throttle opening isn't responding correctly or post a video so we can see and hear the problem.
Each part of the throttle opening uses different jets and components
richardthemotorcycle1
XS650 Guru
Sorry peanut, when I say no throttle I mean to say after my bike starts, and I enguaged the throttle there is no response, when I use throttle my diaphragm slids vibrate but don't move up, and it's like I'm not getting enough gas, now I took carb off again and I have made sure all passages are open, I have carb cleaner spraying out of choke circuits, out the brass tubes, all the jets, out the by-pass holes, check floats again, not sure what else to do.
When the engine is idling and you twist the throttle nothing happens ? is that right?
The engine doesn't increase revs .
The slides lift due to the vacuum created by the engine when you open the throttle valves (butterfly disks)
With the engine off have you tried lifting the slides fully up with your finger and then cover the top air vent at the front of the cab and release the slides.
Both slides should stay up until you remove your finger allowing air into the vacuum chamber above the diaphrams.
If the slides drop then you have an air leak somewhere on the diaphrams .
Make sure that your air filters are not covering the front top vents preventing your slides from rising and that your slides are the right way round with the cutouts facing the engine.
The engine doesn't increase revs .
The slides lift due to the vacuum created by the engine when you open the throttle valves (butterfly disks)
With the engine off have you tried lifting the slides fully up with your finger and then cover the top air vent at the front of the cab and release the slides.
Both slides should stay up until you remove your finger allowing air into the vacuum chamber above the diaphrams.
If the slides drop then you have an air leak somewhere on the diaphrams .
Make sure that your air filters are not covering the front top vents preventing your slides from rising and that your slides are the right way round with the cutouts facing the engine.
richardthemotorcycle1
XS650 Guru
Yeah no rev, I have done the slide test and they are good and sealed. I did notice spraying in where the gas holes goes on, I'm getting more gas coming out of the left float valve.
I don't understand this at all 
You can push your slides up easily with your finger yet when you open your throttle valves the slides don't lift and the engine doesn't rev up ???? something screwy here .
You didn't answer either of my points about the slide orientation and the slide air intake openings.
What is this ?? spraying in where the gas holes goes on
You can push your slides up easily with your finger yet when you open your throttle valves the slides don't lift and the engine doesn't rev up ???? something screwy here .
You didn't answer either of my points about the slide orientation and the slide air intake openings.
What is this ?? spraying in where the gas holes goes on
richardthemotorcycle1
XS650 Guru
sorry for confusing you, I wanted to say when I sprayed my carb cleaner to see if gas was getting to the float valve, to made sure gas was going into float bowl, it seem to spray out both side, just more on the left carb, I'm starting to think its more electrical, my 83 Heritage acted the same way after cleaning because my choke wasn't work right, replaced spark plugs, (that fix it)
