Help me figure what Carbs are on my XS-650 Frankenbike...

[OgreOwner]

I have looked over the material on the stock carbs that came on the XS-650 and how there are stampings to id them. The Carbs on my bike, which I am now calling my Frankenbike as it looks like someone in the past did things to it..., do not have those stampings. If I can figure out how to do it, I will upload pics of all aspects of the carb that is on my bike:

Top View:


















Hopefully the attachments will be visible...

 

[DogBunny]

1970/1971/1972/1973 BS38s.
Check the throttle shaft for slop -- up-down, side to side, in-out. If there is much slop, don't bother with them they will never run right.

 

[lukemylo]

mine had those same carbs.

 

[XSLeo]

For ease of adjustment, get a 76 or later set of carbs.
In 76 is when they went to the linked carbs and a single throttle cable. Your carbs use a straight out carb holder. The 74 up use an angled holder. If you decide to use the later carbs, get a set of 74 to 79 carb holders.
The later BS34's have a bit better throttle responce and will give slightly better mpg's. The only thing is they won't work with your bikes stock air filters or side covers.
Inspect your carbs as Dogbunny said. If they pass then use them. They are a good carb. With the raised floor design I think they will run stronger from idle to 1/2 throttle or so than any of the later carbs.
I have a set like those but the holes in the body where the throttle shaft's go through or very worn. Leak air so bad I can't run them.
If I can figure out a way to repair the holes and get a good seal I would like to try them.
Leo

 

[jd750ace]

I'm already pretty much set to get a pair of EX500 carbs to go on mine.

 

[ippytattoo]

jd, I have a set of ex500 cvk carbs on my '81 and other than putting the last set of mains they are all set and work very well. Right now there is still break-up around 5k rpm but I have the larger mains on hand and ready to go but I have been working on my ardtail so the carbs have been on the back burner. I have an ongoing write up in my build thread so you can see where I have had to go on the jetting. It may save you some time, money on jets and frustration.

 

[jd750ace]

I have read thru a bunch of stuff on the Aussie site, and search here occasionally. I'll follow along. I might try Uni's for filtration, as they are a just a tad more restrictive on average than the K&N pods. Loved my EX when I had it, and it worked well. I'm sure the fueling curve will be a little different, but if I can get them to do what I want up to about 6K, I'm not gonna freak if she won't ton out. Reliable, set and forget, versus the tinker farm is what I'm after.

 

[lukemylo]

i put carbs off a 1980 xs and they work great !!!

 

[650Skull]

72XS2-73TX carbs Carby Evolution wont fit XS1-1B

reading your intro you mentioned soaking the carbs in a can, if you didn't completly strip them then you will have destroyed your shaft seals or any other rubber left in there.

The right carbs for your XS2