Carb slide springs

[heepey]

I have spent most of the summer working on what appears to be a '81 Special. Wiring, cam chain guide, oil strainers, etc. It now starts and idles but dies with any throttle opening. Pulled carbs off and they are a mess and not the correct ones for this bike. They look like early BS38s. Mikes xs has a kit that matches the jet numbers and gaskets. The big problem is there are no slide springs. The slides appear to be early style and the diaphragms look OK. So my question is, "Are there any sources for these springs or alternates that will work in these carbs?"

 

[gggGary]

I have good used ones, a pic of your slides will help me match a pair of the correct length, there were a couple lengths used. .

 

[5twins]

I don't think those springs are available anywhere. You'd need to scrounge some used ones. But personally, I wouldn't waste my time, effort, and money on an early set of unlinked BS38s unless it was an early bike and they were the correct original carbs. I think you'd be better off searching for a whole new set, a later set of linked BS38s or some BS34s (correct for your model).

 

[toglhot]

I personally wouldn't spend any money on BS carbs at all, the prefix 'BS' is a dead giveaway. VMs, Delortos, Webber, even a syringe filled with petrol would be a better choice.

 

[JJames]

I personally wouldn't spend any money on BS carbs at all, the prefix 'BS' is a dead giveaway. VMs, Delortos, Webber, even a syringe filled with petrol would be a better choice.

Those might be too $pecial for a Special.

 

[heepey]

I have good used ones, a pic of your slides will help me match a pair of the correct length, there were a couple lengths used. .

These have the plastic buttons that hold the needle down inside the slide. The bike started and idled but died with any throttle opening.

 

[gggGary]

Do you HAVE springs? they are seldom an issue...
Sorry to be a pain looks like 74 75 bodies can you shoot in the intake?
Not sure it makes all that much difference. I'm headed to the shed I'll look for a pair of springs.

 

[5twins]

Yes, more pics (both sides, front, back, bottom). Some things appear odd with that carb set from what I can see so far. They may not even be 650 carbs. 650 carbs didn't have the fuel line on the outside like your right carb does. Also, it looks like you have a choke assembly on each carb, and the set only uses one throttle cable. '75 and older 650 carbs only had one choke, on the left carb, feeding the rich mix over to the right carb through a short hose. They also used two throttle cables, one running to each carb.

 

[Jim]

I personally wouldn't spend any money on BS carbs at all, the prefix 'BS' is a dead giveaway. VMs, Delortos, Webber, even a syringe filled with petrol would be a better choice.

"Everything in it's place."
Back in the 70's and 80's I used to regularly take my XS' into the mountains of Idaho, New Mexico, Nevada and Colorado. They were the only bikes I had that would go through a 10,000ft pass without have a fit over the ordeal. My RD's, DT's and Brit bikes could only wish they could run smoothly at those altitudes.... if at all.
No, they ain't racing carbs... but when it comes to cross country work, they're the next best thing to fuel injection.
Oh, and they're relatively easy to tune too.

 

[gggGary]

Yes, more pics (both sides, front, back, bottom). Some things appear odd with that carb set from what I can see so far. They may not even be 650 carbs. 650 carbs didn't have the fuel line on the outside like your right carb does. Also, it looks like you have a choke assembly on each carb, and the set only uses one throttle cable. '75 and older 650 carbs only had one choke, on the left carb, feeding the rich mix over to the right carb through a short hose. They also used two throttle cables, one running to each carb.

AHSO I get it now! That piece of fuel hose is being used to connect chokes, for some reason the choke shaft has been hacked in two? Oh boy....

 

[5twins]

Yes, what they may be are XS500 carbs like the set I adapted for 650 use. They are spaced closer together so some parts need to be swapped (top and bottom brackets, butterfly shafts, choke rod) .....

But I suppose, in a pinch, the too short 500 choke rod could be cut and extended via a short length of rubber hose. Those being 500 carbs would also explain the two chokes and the right carb's fuel line being on the outside .....

 

[heepey]

I will get more pics tomorrow. The whole bike is a collection of parts but I had been looking for an XS560 for a while and this was all I could find. The tank is a Kawasaki and it wouldn't surprise me that the carbs are not right for it. The parts linking them are all modified.

 

[heepey]

Do you HAVE springs? they are seldom an issue...
Sorry to be a pain looks like 74 75 bodies can you shoot in the intake?
Not sure it makes all that much difference. I'm headed to the shed I'll look for a pair of springs.

The bike was supposedly running but there were no springs in them when I opened them up.

 

[heepey]

Yes, what they may be are XS500 carbs like the set I adapted for 650 use. They are spaced closer together so some parts need to be swapped (top and bottom brackets, butterfly shafts, choke rod) .....

View attachment 223096

But I suppose, in a pinch, the too short 500 choke rod could be cut and extended via a short length of rubber hose. Those being 500 carbs would also explain the two chokes and the right carb's fuel line being on the outside .....

View attachment 223097

View attachment 223098

These pictures look a lot like what I have but more more cleanly done.

 

[5twins]

Internally, the 500 carbs are the same as a '76-'77 650 set so jetting should be based on that. And the basis would be a 4M1 needle and Z-8 needle jet. The other jets are chosen to work with those 2 components (25 - 27.5 pilots, 125 - 132.5 mains).

 

[heepey]

More pictures of the carbs. 20 inlets, 122.5 mains, 30 pilots, 4J24 needle, Number on the outside of both carbs: 1A8-60 along the lip for the bowls.

 

[toglhot]

Well, there's the problem, I'd be surprised if everything wasn't blocked, there's oxidising, suggesting they have had water in them at some time, and they are pretty darn dirty. It's a good bet some of that oxide and dirt has found its way into jets and orifices. A good, clean, strip down and blow out with compressed air will work wonders. I can see the throttle linkage has been welded up, the choke cross over pipes have been blocked off and a choke plunger installed on both carbs. Looks like they are both left hand carbs. As the throttle linkage has been bodged up, it's a good bet the seals on the at least one of the carbs throttle shafts is cactus. One of the butterfly screws on the left carb has been replaced as well, possibly to swap the linkage around, I'd suggest you check the other end of the screw to make sure it has been mushroomed, you don't want a screw coming loose.

 

[5twins]

Yes, those appear to be '76-'77 XS500 carbs. The jetting you found, plus the fuel line location on the right carb, pretty much verify it .....

If they still have the Y-6 needle jets, which they probably do, I think they will be too lean. Also, I see the bowl vents are capped. They need to be open to atmosphere or eventually a vacuum will form in the bowls and fuel will stop flowing. Originally they had short clear hoses on them but you don't need them .....

 

[heepey]

I would like to make this bike run with these carbs. I can fix most of the issues if I can get the springs and necessary jets. Mike's XS has a kit that looks to be the jets I would need. I would just like to make an around town cruiser; doesn't need to be original just run.

 

[heepey]

Yes, those appear to be '76-'77 XS500 carbs. The jetting you found, plus the fuel line location on the right carb, pretty much verify it .....

View attachment 223545

If they still have the Y-6 needle jets, which they probably do, I think they will be too lean. Also, I see the bowl vents are capped. They need to be open to atmosphere or eventually a vacuum will form in the bowls and fuel will stop flowing. Originally they had short clear hoses on them but you don't need them .....

View attachment 223547

Yes the needle jets are Y-6.