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Yep. Also with the 76-and-forward carbs it's possible to vary idle speed adjustment independent of synch adjustment, and there's no fiddling involved matching slack on two throttle cables to get the throttle plates opening at the same time.
Take Warning15
XS650 Addict
OH, so I would need a new single cable and new throttle cable assembly? Or could I just use what I have? I have two separate throttle cables now.
I think you can use what you have now, just remove one cable from the twist grip. Eventually, for a neater look, you may want to pick up a later single cable throttle assembly (housing and twist grip). Be aware that assemblies '79 and newer will not have the on/off headlight switch. That was eliminated from the housing after '78.
Take Warning15
XS650 Addict
As always, thanks a lot!
not sure if this is the right place to post this but it is relevant I guess.
I was checking my carbs today as they were refurbed by the PO
I noticed that one of the floats was set at 21mm height which I assume should be 25mm?
However the thing that concerned me the most was the angle of the float tang which was set at approximately 45 degrees to the float needle jet
The Float Tang must contact the float needle exactly perpendicular to the Float Needle or else the float tang will apply a sideways pressure to the Float needle in operation and quite likely cause the Float Needle to stick and bind against the side of the needle tube wall.
The only way the Float Tang can be made to contact the needle on this carb is for the float bracket to be realigned . I am not sure if these floats are original or aftermarket replacements but they are s**** quality either way
I was checking my carbs today as they were refurbed by the PO
I noticed that one of the floats was set at 21mm height which I assume should be 25mm?
However the thing that concerned me the most was the angle of the float tang which was set at approximately 45 degrees to the float needle jet
The Float Tang must contact the float needle exactly perpendicular to the Float Needle or else the float tang will apply a sideways pressure to the Float needle in operation and quite likely cause the Float Needle to stick and bind against the side of the needle tube wall.
The only way the Float Tang can be made to contact the needle on this carb is for the float bracket to be realigned . I am not sure if these floats are original or aftermarket replacements but they are s**** quality either way
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Yes, something's not right. Your floats appear to be originals but who knows. The tang usually ends up near horizontal, even on the BS34 plastic floats .....
Two ideas come to mind. First, maybe the float needles were replaced with incorrect (and shorter) ones. Second, maybe the spring-loaded pin in the float needle is stuck in the compressed position. They can do that if they get gummed up. I can probably measure the length of a correct float needle if you need that for comparison to what you've got.
One more thing, if your carb set is a '78-'79, float spec is 24mm ± 1mm.
Two ideas come to mind. First, maybe the float needles were replaced with incorrect (and shorter) ones. Second, maybe the spring-loaded pin in the float needle is stuck in the compressed position. They can do that if they get gummed up. I can probably measure the length of a correct float needle if you need that for comparison to what you've got.
One more thing, if your carb set is a '78-'79, float spec is 24mm ± 1mm.
yep I concur 
The PO had obviously made some adjustment as there are some fresh tiny scratches on the tangs.
God knows how these carbs actually worked .
The needle springs are free and clean but your idea about them being too short is a good one.
I'll remove them and measure.
I assume these carbs are origninal 78-79 SPll but the PO had refurbed them so its entirely possible he fitted the wrong length float needles
My float brackets look quite different to yours
The PO had obviously made some adjustment as there are some fresh tiny scratches on the tangs.
God knows how these carbs actually worked .
The needle springs are free and clean but your idea about them being too short is a good one.
I'll remove them and measure.
I assume these carbs are origninal 78-79 SPll but the PO had refurbed them so its entirely possible he fitted the wrong length float needles
My float brackets look quite different to yours
You might also want to check the float needle seat. It should have a seal washer under it where it screws into the carb body. Without it, the whole assembly would sit lower and possibly explain the need to bend the tang more to achieve a proper setting.
thanks i'll check that. I can see i'm going to need to strip check and rebuild these carbs or they'll never work.
Heres the needle 12.2mm shaft and 2.4mm spring 14.6mm total length and carbs for ID.
i notice the main jets are 145 !?
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To I.D. the carbs, I'll need to see the other side (where the air filter attaches) and the float bowls. Yes, they are a later linked set but that could be '76-'77 carbs as well. There were two linked sets of 38s used and they differ quite a bit in both jetting specs and construction details.
145 mains aren't totally off the wall if this is a '78-'79 set. But they would probably be about the max you'd need or want. 140s or 142.5s are the norm for basic "pipes and pods" type mods.
145 mains aren't totally off the wall if this is a '78-'79 set. But they would probably be about the max you'd need or want. 140s or 142.5s are the norm for basic "pipes and pods" type mods.
OK, from that added picture, it's official - you have a '78-'79 carb set. I checked some float needles and they measure the same as yours. What may be different is the float needle seat. Your carb set should use a #2.0. The '70 and '71 carbs used a #2.5. That means the hole in it would be bigger and that may cause the needle to sit in there lower. Maybe the P.O. put those 2.5's in by mistake? Also, some measurements on the seat - total length top to bottom is about 14.4mm. This includes a lip on the bottom for a filter screen to snap onto. Some of the aftermarket replacement seats may not have that lip. Then the overall length would be more like 12.5mm.
thank you 5twins that is very helpful . I appreciate it.
Tomorrow I'll strip the carbs so that I can familiarize myself with its construction function and jet sizes etc .
Because of the big discrepancy in position and angle of the float tang I feel certain I will need to bend the float pivot bracket to a sharper angle which will allow me to bend the float tang up level where it should be.
I will also check the needle valve seat size , thanks for the tip and images .
Tomorrow I'll strip the carbs so that I can familiarize myself with its construction function and jet sizes etc .
Because of the big discrepancy in position and angle of the float tang I feel certain I will need to bend the float pivot bracket to a sharper angle which will allow me to bend the float tang up level where it should be.
I will also check the needle valve seat size , thanks for the tip and images .
That solder job on your float where the bracket attaches looks rather heavy. Maybe it was a P.O. repair of some sort. I can get some better pics of factory stock floats from different angles if you need them. Maybe that will show if your bracket is mounted or bent differently. The side view a couple posts up is all I have at the moment.
I'm kinda seeing that, too. 5Twins' float bracket pic seems to have more bend at the pivot point, lowering the whole bracket to proper valve tip height, and peanut's float bracket seems to not have enuff bend, raising the whole bracket, requiring the tang to be bent down.
Kinda like this, but upside-down:
C------ 5Twins
C_____ peanut
Brian902
XS650 Junkie
Just checking, but Peanut are you measuring from the raised edge of that carb?
Should be the gasket surface with gasket removed.
Should be the gasket surface with gasket removed.
I didn't even notice that but I think you're right. Still, 21mm from the raised edge probably equates to 24 or 25mm from the gasket surface. But that tang is still at a 45° angle so something is amiss.
yes you are right Brian I was measuring from the raised edge of the chamber but I realised that today.
5twins you were right about the missing fibre gasket under the float valve #6
There are quite a few things missing and a stripped thread on one of the float chamber fixing holes. ( the only one thats too shallow to drill and tap
) Not sure how I am going to fix that at the moment because the fuel bowl is bound to leak with only 3x fixing screws
The shouldered spacer #37 is missing off the cold start fixing.
The carbs are a mess to be honest . Nothing is correctly aligned or working properly. Whoever threw these together had no mechanical understanding or finesse
I'll see if I can order up a car refurb kit and buy a used set of carbs to use as a donor.
Thanks for all your help on this. Your level of expertise is impressive
5twins you were right about the missing fibre gasket under the float valve #6
There are quite a few things missing and a stripped thread on one of the float chamber fixing holes. ( the only one thats too shallow to drill and tap
) Not sure how I am going to fix that at the moment because the fuel bowl is bound to leak with only 3x fixing screwsThe shouldered spacer #37 is missing off the cold start fixing.
The carbs are a mess to be honest . Nothing is correctly aligned or working properly. Whoever threw these together had no mechanical understanding or finesse
I'll see if I can order up a car refurb kit and buy a used set of carbs to use as a donor.
Thanks for all your help on this. Your level of expertise is impressive
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These carb from a company that built many versions of it. Some are very close, others not even. They made the changes to the carbs to fit the specs of the bike the carbs fit.
The carb kits come with parts that will fit in your carb but not fit your application. Buying the kits you may get parts you can use but not often.
Your best bet is to just buy the parts you know you can use. Most of the kits the float bowl gasket is usable, most of the brass parts aren't.
Leo
The carb kits come with parts that will fit in your carb but not fit your application. Buying the kits you may get parts you can use but not often.
Your best bet is to just buy the parts you know you can use. Most of the kits the float bowl gasket is usable, most of the brass parts aren't.
Leo
