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First bike, first build!

Discussion in 'The Garage' started by Fullmetal, Nov 12, 2014.

  1. Fullmetal

    Fullmetal XS400 Enthusiast

    What's going on guys? I've been a fan of motorcycles ever since I was young, and it's always been a dream of mine to own one. Well, my 22nd birthday is just around the corner and I figured now was the time! I jumped onto craigslist and 2 days later I came home, now the proud owner of a 77 Yamaha XS360!


    Only 2 previous owners, with 15xxx miles on the motor, and it's still fully functional. The guy I bought it from mentioned that the carbs would need some adjusting, but other than that, the bike feels like it came straight from the factory still. I've had it for about 3 weeks now, but I'm a complete noob when it comes to motorcycles (most of my friends are car guys, although that doesn't help much haha.) I've done some basic stuff, like changed the oil, replaced the shift lever (the original had been rewelded before, but very poorly), run some seafoam thru the system, but there are things I've noticed with the bike that need to be addressed:

    1) I noticed the carbs leak gas while it sits overnight. Usually, only the bottom half (where the floats are) are wet.
    2) The petcock leaks when I have it set to reserve, and I'm pretty sure it's not supposed to do that haha.
    3) When the bike is cold, it idles low and roughly, but when it's warm, the idle is very high (in between 3000-4000)

    That's all I've noticed so far. I know I probably need to take apart the carbs and clean them, but tinkering with them is a foreign concept to me. Over the winter, I want to make the bike into a mix between a tracker and a bobber but retain the original look of the bike (the paint is chipped in places, but it's almost perfect.)

    I have more to say, but unfortunately I'm running out of time in class so I have to end it here (for now). If anybody can help with the current issues I have, that'd be great. I appreciate any and all feedback and look forward to spending much time here. Cheers!
  2. Sesty

    Sesty H.E. Pennypacker

    nice looking bike!

    definitely clean those carbs a few times, there are some good videos and walk-throughs on just how to clean them on this site. Then build a manometer and sync the carbs

    the float needles maybe dirty and letting gas flood the carbs, make sure no gas got in the oil before you ride it.
  3. levdir

    levdir Rounded bolt brigade

    Welcome to the forum!
  4. trzcina2

    trzcina2 XS400 Enthusiast


    Nce bike! I definitely envy your rims! :thumbsup:
  5. BBS360

    BBS360 XS400 Guru Top Contributor

    Looks like a great bike!

    I'd say the build is done. :thumbsup:

    Can I ask what you paid?
  6. Fullmetal

    Fullmetal XS400 Enthusiast

    Sesty: Thanks! Before I figured out the petcock was leaking, a little bit of gas got into the oil (thankfully it wasn't being ridden during this time). She's now got clean oil and cleaning the carbs is the first thing on my to-do list!
    levdir: Thanks, glad to be here!
    trxcina2: Thanks!
    BBS360: Thanks, I paid $1050 and don't regret it one bit!

    Regarding my future plans for the bike, like I mentioned, I like the philosophy behind cafe/bobber style bikes but I've grown to like street trackers as well. So what I'm thinking is to give it the body/stylings of the former and the heart and soul of the latter. I also don't want to do anything that can't be undone, so I can save the stock parts. Idk if it's possible, but here's my plan so far:

    -Teardrop style gas tank (would one off a similar year xs400 be a direct swap?)
    -A slimmer, shorter seat
    -Front end swap
    -New rear shocks
    -Pod filters
    -2 to 1 exhaust with a shorty muffler
    -Engine internals (idk if that's even possible on this bike, but I would love to do something here)
    -Smaller turn signals, replace headlight/tailight, smaller gauges, move the battery box, etc. (typical cafe/bobber stuff)

    Right now, there's a big chance my area will receive snow tomorrow, so I'm gonna use this chance to take off the carbs and give them a really good cleaning. Hopefully they're not in too bad of shape, but you never know with a 37 year old bike!
  7. Fullmetal

    Fullmetal XS400 Enthusiast

    Been a bit busy, my band just got back into town this morning. Before I left, I managed to tear apart the carbs and get them cleaned up. To my surprise, they were pretty clean already and the gaskets looked new. I'm guessing the PO had already rebuilt the carbs. Which is less of a headache for me, I suppose haha. Only thing I really have to replace are the carb boots, which were pretty dry rotted.

    I haven't had the time to start rebuilding them yet, but I should have time tonight. I bought some pod filters the other day, as well as replacement boots. While I'm doing all this, I really want to swap the exhaust to the 2-into-1 setup, but I'm having a difficult time finding a good set. I've seen the MACs but most of the ones I find are for 80s model XS400, which I've heard would be different than late 70s model. Is there any truth to that?
  8. Fullmetal

    Fullmetal XS400 Enthusiast

    Life's been a bit hectic these past few weeks. Haven't had much time to really do much to the bike until today. I finally put the carbs back on the bike, fresh boots and everything, and wanted to take her for a quick ride before I installed the pod filters.

    However, when it came down to it, the bike just wouldn't fire up. I noticed a few things that I don't remember being around before I started working on the bike.

    1) Every other kick or so, there was a "dead spot" where the kickstarter would pretty much stop in it's place before really even turning the cylinder. After that would happen, it'd kick over like normal (but still not starting) for a turn or two before hitting another dead spot. Could this be a clearance issue?

    2) After some kicks, it literally sounded like the engine was gasping for air, or at least pulling a lot in (or maybe forcing some out?) I took off the airboxes to see if this would help, but every so often it'd still gasp.

    I haven't really found much info on either problem, so I'm hoping someone can help a brotha out!

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