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New member, new bike, and some questions

Discussion in 'The Garage' started by Nichalus, Mar 18, 2023.

  1. Nichalus

    Nichalus XS400 New Member

    Hello, first post on the forums and was looking for some advice.

    Last fall I obtained my first street bike, 1982 xs400 heritage special. It was my boss's, she rode it a little bit a few years ago, had a kid, and quit riding it. It sat in the garage for 4 years and her husband recently took the carbs off and sent them to a friend for cleaning to get the bike running again.

    They got a divorce, she said if I could haul the bike away it was mine, and the carbs were never seen again and never will be :p

    So the weather here in Michigan is just starting to break and I am getting the urge to get this bike running and take my very first ride down the road on my first bike. But I've run into some problems with my original plan, "buy carbs off eBay, rebuild, grease and inspect everything, ride."

    My vin number and title shows the bike is a 1982 xs400. But the stamp on the engine says 360cc. I do not know much about Yamahas (Honda ATV guy), could this be a swapped in engine?

    Distinguishing factors I know about my bike:
    -Spoked wheels
    -Manual drum brakes front and back
    -Electric start, glass fuses (will be upgraded to modern fuse block)
    -Six speed, 1-N-2-3-4-5-6

    My questions for the experts:

    -Were the 400's only bored to 360cc? I thought there was a separate bike, the xs360, is that bored smaller or do I have an xs360 engine in my xs400?

    -Consequently, should I order carbs for the xs360 or xs400 for this bike?

    -Mike's XS has a "performance" new carb kit that includes intake manifold, throttle cable, and nice filters for a price cheaper than used carbs and rebuild kits... would it be foolish to toss a non-stock setup onto a non-running bike? It would be so much easier as I need intake manifolds and a cable anyways, and it's all in one neat kit for a decent price.

    Thank you for all your help, this is my first street bike and first Yamaha and I am super excited to learn the ropes on it. I am relatively mechanically inclined with engines from cars and bikes, but these decisions stump me a little bit since google doesn't offer much good information on these bikes and their differences.

    Attached are a few pictures of the dusty bike when I brought it home. If engine numbers or close up photos are needed I'll grab them right away! Apologies for my girlfriend's judgemental face, she wasn't the happiest to be woken from a nap to unload a dirty motorcycle I brought home. IMG_20220910_123631483_HDR.jpg IMG_20220910_192107552_HDR.jpg
  2. CaptChrome

    CaptChrome XS400 Addict

    Welcome to the forum! Nice score on the bike, but I think you are about to find out that free bikes aren't always cheap.

    The bike is indeed an SOHC Heritage Special that looks pretty complete. The engine, however is not the original. I can see from the pictures that it has squared off fins on the cylinder block and head that the specials don't have. If the casting on the cylinders says 360cc, then it is probably an engine from an XS360 - can you post the engine number that is stamped on the crankcase right side near the kickstart crank? We can use that as additional evidence as to what carbs you need.

    If you are going to have to get carbs anyway, I would probably consider the Mikuni VM series round slide carbs. I don't have any knowledge of the MikesXS stuff, but the Mikuni VMs might be easier in the long run with tuning advice and jetting, and they work well without the stock intake setup. One source that sells complete kits for either the XS360 or XS400 is at https://speedmotoco.com/yamaha-xs360-carburetor-kit---mikuni-vm30-carburetor-kit---replacement-kit/
  3. Nichalus

    Nichalus XS400 New Member

    Thank you for all the information. I know this bike will cost me much more than what it takes to get it running, I've got a 1982 Honda ATC 185s, and have obtained a few old machines to fix and get attached too I mean sell. I have known my boss for years and trust that the bike was running when parked, and all it needs to get it running is carbs, but there will be many things to find a long the way broken, rotted, leaking, etc. on a vintage machine like this. Still doesn't steal my love for old bikes!

    I don't recall the exact number, but I think this bike (or at least the odometer on it, but the general condition seems to back it up) has only 14k miles. Everything is in great condition but I have been re-greasing and inspecting everything for good measure. Not to mention replacing all the crusty old electronics I don't want to trust. Tires are in great condition and were new right before storage, and the bike was stored off the ground too.

    I will have the engine number posted tomorrow afternoon after work. I will check out speedmotoco for carbs and supplies in the meantime.
    CaptChrome likes this.
  4. Nichalus

    Nichalus XS400 New Member

    Engine #1T6-005349
  5. CaptChrome

    CaptChrome XS400 Addict

    Yup, it's an XS360 engine. Specifically the "1T6" is the model code and the numbers following it are the serial number. 1T6 is the code for a 1977 XS360-2D. Your bike VIN should start with "14V" which is the code for a 1982 XS400SJ.

    One thing to check for is if the person doing the engine swap removed the TCI box (electronic ignition) from the bike. The 1980-1982 SOHC 400s used this instead of a points ignition. It is mounted to the underside of the battery box and looks like this:

    If it is there, remove it and store it off of the bike. You can sell this on the marketplace here to some needy owner with a fried box and offset some of the cost of buying the new carbs.
  6. CaptChrome

    CaptChrome XS400 Addict

    Holy Frankenbike Batman! I just relooked at the first picture that was posted. It is hard to tell, but it looks like the engine swapper retrofitted the electronic ignition to the XS360 motor. It looks like the bike is using the late model cam rotor cover and not the points cover and there appears to be the wires from the pickup coil coming out of that cover leading up under the tank to plug into the wiring harness. If this is the case, the TCI box will definitely be mounted under the battery box, and you should leave it right there because you need it.

    If this is true, then whomever did the swap, I salute them!
  7. Nichalus

    Nichalus XS400 New Member

    That's funny, in my learning journey about this bike I was reading somewhere that they made the change from points ignition to electronic ignition somewhere down the model line. When I start tearing into the electronics in the next few weeks I will survey what kind of system one of the previous owners fitted to this bike. I know my boss sure didn't lol. Good thing you brought it up, I would have just overlooked it!
  8. CaptChrome

    CaptChrome XS400 Addict

    I think you are going to find that the ignition components you now have on that engine are stock XS400 ones that were removed from the original engine and "transplanted" onto the donor engine. A transplant was also done with the starter motor and associated bits as it sure looks like there is a power wire going to the housing where the motor is. XS360-2D bikes did not have a starter, they were kick only. If you have electric start, that was added to the donor engine as well.

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