Kdobbs '82 Build Thread

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Kdobbs372

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Hi everyone. I’m new here on this forum. I’m new to the XS 650 community. I’m finding lots of great information here.

I just acquired a 1982 Yamaha XS 650.I am not sure what carbs I have as all this is new to me. They look very rough and I will need to rebuild. I’ve heard different opinions about different carbs.

Can someone help identify these for me? Should I rebuild these or should I go to a totally different carburetor? If so, what is your recommendations? Best carb rebuild kit? Etc? Thanks to everyone for there help.
 

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Off hand they look to be in pretty good condition - you’ll know more when you open them - don’t be scared if they are full of goo from old evaporated gas - here is a couple of examples how bad it can look and how they can turn around and be useful again.
As already mentioned original mikuni jets/needle etc - I did make some bowl seal on my own though - these are BS38, but same concept.
 

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Like everyone sez...
BS-34's. Good/great carb.
Don't be afraid if they're gooped up.... 90% of the time you can save 'em.
Avoid non- Mikuni brass like the plague. Nobody makes a kit that's worth a shit... buy the individual genuine Mikuni bits.

Once you get the carbs sorted, run non-ethanol gas exclusively. Do that and you'll never have to open 'em up again.

Another good source of genuine Mikuni brass...
https://www.jetsrus.com/
1740502756295.png
 
Kdobbs372 said:
You guys are the best. I’m a little overwhelmed by this project. But asking questions and referring to manuals and getting the right tech specs. I think I can handle it. Thanks again to everyone.
Click to expand...
These carbs are relatively easy to work on... as carbs go. On a scale of 1 to 10, I'd say they're a 3 or a 4.

Take your time, read the carb guide 'till your eyes bleed. Cleanliness is everything. Shop air and a blow gun is your best friend here...
Well, that and this forum. You can do it.
 
Those intake boots look to be the original 40+ yr old boots. Best thing you can do is toss 'em in the bin now and order new ones. Look for ARS branded boots, not the Chinese junk ones. Ask here before you order.

If I'm not mistaken, Cruisinimage has 'em... at least the made in Japan ones. have a look there.

https://www.cruzinimage.net/
 
Jim said:
Those intake boots look to be the original 40+ yr old boots. Best thing you can do is toss 'em in the bin now and order new ones. Look for ARS branded boots, not the Chinese junk ones. Ask here before you order.

If I'm not mistaken, Cruisinimage has 'em... at least the made in Japan ones. have a look there.

https://www.cruzinimage.net/
Click to expand...
I found that the ones I recently bought branded Tourmax are marked ARS and are Japan made. Cruzinimage likely have the same or similar.
 
OK everyone I’ve got the carbs pretty much apart. The Jets seem really buggered up at least where you try to get the flathead into them. I can’t tell what size jets they are. Not sure how to read or I don’t see any numbers. Plus I have these little mystery black rubber things as pictured inside one of the orifices of each carb. Not sure what’s going on there. So if I want to order all new jets are there specific sizes I need to order? Please see pictures and again thanks to all for all your help
 

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Drain is here. Loosen the screw and fuel comes out the bottom.

1740532138737.png


Where your chunks of rubber are is supposed to be a small round rubber plug. You'll need to order 'em.

All your other questions, such as the plastic floats and jet sizes and such are answered in the carb guide... the one I suggested you read and reread... which apparently you ain't... :er:

Did you do a slide drop test before you tore 'em apart? That's in the carb guide, so I'm guessin' you didn't...
 
Btw, I don't mean to come off as a harsh asshole, but following directions is kinda important when people are trying to help you. Eventually they'll just throw up their hands and quit offering help.
So take it in the spirit intended... trying to help you.:)
 
Kdobbs372 said:
So if I want to order all new jets are there specific sizes I need to order?
Click to expand...
@Wingedwheel and @Jim gave you the places to buy jets. Both sell OE and aftermarket. Be careful what you're buying. Get genuine Mikuni.

From memory:
pilot jet #42.5
main jet #135

If you really want to do this right, you need JIS screwdrivers, at least a #2. You may want to replace the butterfly shaft seals and float valve o'ring. You'll find those in the tech section under GREAT O'RING THREAD or something like that. At the carburetor store, buy float bowl gaskets.
 
 
Last edited:
Jim said:
Btw, I don't mean to come as a harsh asshole, but following directions is kinda important when people are trying to help you. Eventually they'll just throw up their hands and quit offering help.
So take it in the spirit intended... trying to help you.:)
Click to expand...
Oh I did and thank you! Sometimes I get ahead of myself and I need reminded to slow down, educate and take my time. I just downloaded it and am now digesting it line by line. Again, thank you!
 

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