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Need help with 1977 XS400 Carbs

Discussion in 'The Garage' started by Shaun, May 16, 2023.

  1. Shaun

    Shaun XS400 New Member

    Hi All,

    This is my first post on this forum as well as my first bike! I recently purchased a 1977 Yamaha XS400 off of a gentlemen from Facebook for $75. He bought it from a family member as a parts bike but offered to sell it to me as a rolling chassis initially but threw the engine in because he didn't want to go through the hassle of selling it. The engine works but he took one of the carbs for his other XS400 build. I'm not sure where I would purchase a new set of carbs for it. I'm a younger guy and very new to motorcycles so this is my first I plan on converting. Any help on where to find new carbs or any generic replacements that fit would be greatly appreciated.
    Archilles likes this.
  2. tstidham

    tstidham XS400 Addict

    For factory carbs, mikuni bs34 off ebay is probably your best bet. Mikesxs has a performance carb kit available, but you'll need to put pod filters on them and likely need to do some customization and tuning. If your missing the factory air filter hoses and stuff anyway, this may be a good option anyway.
    Archilles likes this.
  3. Shaun

    Shaun XS400 New Member

    thanks! should I go with mikesxs's carbs or can I run some ebay carbs of the same size? What are the downsides of not using oem carbs?
  4. gpounce32768

    gpounce32768 XS400 Enthusiast

    I'd go for ebay carbs unless they're really rough; designed and jetted for the bike, they'll fit properly and so on. OTOH maybe the mikesxs carbs would fit and be fine- might be a good deal if they're complete. old nasty ebay carbs may have lots of other issues besides clogged; wrong jets, leaky/missing floats, leaky/missing float valves, diaphragm and needle issues.. the list goes on and on like the worst record album of all time.

    My move would be to compare prices and risks, then gamble on what I'm willing to lose. Theres no certainty when bring back a basketcase. I'm reluctant to add up what I dumped into my '82 Seca to get it in shape- a significant part of the money being wasted pursuing dead ends. But I do it for fun, so whatevs..

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