XS650 Mikuni BS38 on 1980 xs650...

As the ad says, you'll need manifolds for the 38s, different size than the 34 ones. It appears that set is a "mix and match" from several years. It is also missing the butterfly shaped bracket that ties the carb tops together. You should disassemble and examine all the internals. The main bodies are '78-'79 but the float bowls are '77 or older. From the jet sizes they claim they put in, the bowls may be '75 or older. '76-'77 carbs used a 122.5 main. '78-'79 carbs used a 135. Neither set used 42.5 pilots.

The seller claims to know and sell XS650 stuff. They obviously don't know much about the carbs. Or maybe they're just another dishonest eBay seller.
 
In the third picture (left side of carbs) they have drilled a hole in the throttle lever and added a big spring, I guess to help close the throttle, probably because the throttle plates are binding and not closing like they should.
 
I forgot to mention to everyone that I am 100% new to bikes (building, at least). Do you know of anywhere that has some info on taking apart/cleaning/assembling the carbs? I don't want to just start unscrewing shit...
 
http://jbmindustries.com/HOLDERS.html for manifolds

The "bible" on the stock carbs. http://www.amckayltd.com/carbguide.pdf

Like Leo sez read it till your eyes bleed. Straight up? That set of carbs is going to drive you nuts. They look more like a pile of parts than a set of carbs for a newby to work on. The good news is that you probably can't make em much worse than they already are.
 
Last edited:
gggGary said:
http://jbmindustries.com/Yamaha650.html for manifolds

The "bible" on the stock carbs. http://www.amckayltd.com/carbguide.pdf

Like Leo sez read it till your eyes bleed. Straight up? That set of carbs is going to drive you nuts. They look more like a pile of parts than a set of carbs for a newby to work on. The good news is that you probably can't make em much worse than they already are.
Click to expand...

fuck. not what i was looking to hear, but thanks for being straight forward. what would you recommend? how much trouble would it save me to buy a different set of carbs?
 
Well I would recommend..........
You might want to PM retired gentleman see what he could do for you with that set of carbs as a start. Those carbs do have worth, hard to tell how much without seeing the insides but rebuilders need parts carbs and those may have useable parts for a rebuilder. The thing is a guy that knows his way through a set of carbs with some other sets to pick parts from could build up a set. You will pay more trying to get a complete set of working carbs out of those than you paid for them (by a long shot) Do you have good manifolds? BS34s can be had for your bike and are about the same or a little easier to work on.
 
gggGary said:
Well I would recommend..........
You might want to PM retired gentleman see what he could do for you with that set of carbs as a start. Those carbs do have worth, hard to tell how much without seeing the insides but rebuilders need parts carbs and those may have useable parts for a rebuilder. The thing is a guy that knows his way through a set of carbs with some other sets to pick parts from could build up a set. You will pay more trying to get a complete set of working carbs out of those than you paid for them (by a long shot) Do you have good manifolds? BS34s can be had for your bike and are about the same or a little easier to work on.
Click to expand...

I started this thread to figure out which manifolds I needed but I don't have any as of now. I'll message that guy, but should I start looking for a pair of bs34s in the meantime? And what would you say I should be ready to spend for a decent pair?
 
I don't want to pop your bubble, really. Those carbs could be usable but experience says "maybe not" I guess we want to help but the info about what you have, want to do, is a little thin. Overhauled carbs start at 1-120 go to $300+ the trick is getting a set that really is in running condition for your bike where you live.
 
gggGary said:
I don't want to pop your bubble, really. Those carbs could be usable but experience says "maybe not" I guess we want to help but the info about what you have, want to do, is a little thin. Overhauled carbs start at 1-120 go to $300+ the trick is getting a set that really is in running condition for your bike where you live.
Click to expand...

honestly, my goal is to get this bike running obviously. i guess what i'll do is keeping talking to people about these and hopefully find someone near me more knowledgeable than me to take them to and have a look at them to tell me. ill go ahead and buy what i need to fit these to my engine and take it from there. if they turn out to be worthless, i guess ill have to buy the other ones. my uncle is a builder in california and he wins all sorts of awards and shit constantly, so i e-mail him questions...but i need someone face to face...and he's in california :(
 
I have a set of 76/77 BS38s that I will sell to you for $100 plus actual shipping.

I will guarantee that:
1. every bit and piece is there, is in the correct place, and is correct for 76/77
2. the diaphragms are good (no holes)
3. everything that is supposed to move does move: diaphragm assembly, choke plungers, throttle plates, floats

I have not removed the floats, so I don't know if they have holes, but I have no reason to believe they do have holes in them

You will have to disassemble and thoroughly clean everything, but it's not that hard with the carb guide and the exploded drawings.
You may have to replace rubber parts, such as the jet nozzle o-rings if you get that far into disassembly. I will even throw in a pair of those o-rings -- I bought a bulk supply of them a while back.

I know my way around BS38s, and I will try to help you if you have problems.

PM me your email and zip code, and I will send you pics and shipping cost.

The $100 is more than eBay, but the eBay ones don't come with my guarantees.
 
gggGary said:
Well I would recommend..........
You might want to PM retired gentleman see what he could do for you with that set of carbs as a start. Those carbs do have worth, hard to tell how much without seeing the insides but rebuilders need parts carbs and those may have useable parts for a rebuilder. The thing is a guy that knows his way through a set of carbs with some other sets to pick parts from could build up a set. You will pay more trying to get a complete set of working carbs out of those than you paid for them (by a long shot) Do you have good manifolds? BS34s can be had for your bike and are about the same or a little easier to work on.
Click to expand...

Thanks Gary, for your faith in my carb abilities, but I'm not a carb repair guy. As recommended already, darienmd should read the carb guide and learn as much as possible about his carbs. Perhaps he can find some carb help locally in Florida.
 
retiredgentleman said:
Thanks Gary, for your faith in my carb abilities, but I'm not a carb repair guy. As recommended already, darienmd should read the carb guide and learn as much as possible about his carbs. Perhaps he can find some carb help locally in Florida.
Click to expand...

i saved a link to that carb guide and plan on spending sunday going through it multiple times. thank you guys for all the kind words of wisdom!
 
The carbs are basically identical so if you only work on one at a time you still have a pattern to go by.
Don't go poking stiff wire around in the holes till your sure what you are poking.
Most of the holes are a certain size for a reason.
Carb cleaner in aerosol cans is handy for flushing those holes, be careful and wear eye protection it can blind you.
 

Similar threads

DogBunny
would this oil pressure gauge work?
Replies
6
Views
751
Superjet
Superjet
S
XS1 handle switch
Replies
5
Views
1K
Sarilhos
S
TwoManyXS1Bs
CruzinImage BS38 carburetor floats -- Review
4 5 6
Replies
100
Views
16K
Marlin72xs
Marlin72xs
Aucbar
Sissybar for xs650-D
Replies
6
Views
2K
Aucbar
Aucbar
scott s
Help me find this seat
Replies
3
Views
1K
scott s
scott s
Back
Top