Noob Owner Carb Struggles

[Chris Rabenhorst]

Hello All,

Longtime bike owner, first time XS owner. Now i’m wading through a new bike with a lot to learn. It’s titled as a 1979 XS650F that was bobbed by a builder in Denver around 2010 / 2011. As it has sat awhile I’m giving it some TLC. I’m replacing the cracked carb holders and have run into my first question. From my initial read, the carbs should have been 38MM. They actually measure 34MM and i’m having a hard time ID’ing them online. Any help is greatly appreciated.

Thanks,
Chris

 

[Scharst]

I believe those are off of a Suzuki drz400

 

[5twins]

Yes, those are not original 650 carbs. A popular swap is the carbs off a Kawasaki EX500 which is what they may be. Do a search here for that, there's a giant thread on fitting them.

 

[650Skull]

These are EX500 carbs.............

 

[5twins]

OK, so those aren't them, lol.

 

[grizld1]

The EX500 carbs are Keihins, the pics Chris posted show Mikunis. Don't know about the DRZ, though; would have been quite a chore fabricating brackets, choke actuator, and throttle shaft to link a pair of those. Chris, there's no data pool on those late Mikuni vacuum lifted flat slide carbies on the XS650, but they're dedicated 4-stroke carburetors and tuning should be a fairly easy process. If you check out everything else first, you'll spend less time chasing your tail. The PO made a major mistake by installing those cone filters. Vacuum carbs like still air at the intake, and your best bet is to hook up to the OE air box if you can. If you have to use pods, use Uni foam filters.

Edit: just looked again; Scharst, you're probably right, those are singles with both bell cranks in place instead of a common throttle shaft, probably not even bracketed. Good luck, Chris; if that's a sample of the PO's skills, you'll need a lot of it.

 

[Beags64]

BST34's? These are the center two of four, was told they came off a GSXR. Plan is to try the other 2 on my '78 motor. One good thing is angled carb holders flipped over puts the float bowls back to level.

 

[gggGary]

What is that?

It scares me.