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New XS500 member, I hope you'll accept me. Starting frustration

Discussion in 'The Garage' started by Daniel Moulton, Mar 3, 2022.

  1. I know the xs500 is a bit of a downer in the XS line but I cant find a forum for them, so I hope youll accept me.
    I am working on a 76 XS500 cafe. I picked up the bike up for $100. After a lot of work I tested to see if it would run and I got it running enough to give me the confidence to keep going.

    Im now at a point to get it started again but she wont turn over. I get a backfire(misfire?) while using the starter fluid or when I use the kickstart from both cylinders but thats about it. I have a checklist of things it could be and checked off just about all of them.

    New starter solenoid
    New spark plugs
    New spark plug wires/boots
    Good spark
    New petcocks
    New fuel line/filters
    Brand new carbs w/ new jets (Mikuni 34M)
    New pod air filters
    Carb bowls full
    Fuel Air mix screw is out 2 turns
    idle screw is out about halfway
    Choke in
    Good battery charge (Antigravity 8 cell)
    throttle assembly working correctly
    Starter motor works (although it sounds a bit slow but I may just be going crazy)
    Oil is clean and full
    Tested compression and its well within the recommended range on both cylinders
    No fuses blown (Using the Motogadget M Unit)

    Im at a loss. The next thing ill try is removing the starter and taking that apart to see if anything is going on there, but is sounds like its not getting fuel making a "Chug-A-Chug-A-Chug" while occasionally giving me a giant backfire. Any advice or direction would be amazing
  2. CaptChrome

    CaptChrome XS400 Addict

    Welcome to the group! I can't speak for anyone else but me, but a bike is a bike and they are all interesting in their own ways. And I think you can learn a lot about your own machine by reading about someone else's experience with a completely different machine. These old bikes are really pretty similar.

    Anyway, about the issue - what do you know about the timing setup? I don't see that on the list and am wondering what you have checked or done with it.
    Daniel Moulton likes this.
  3. Thats probably because I havent checked anything with the timing. This is my first bike that uses points so I will need to do some research. Is there something specific that ill need to check? YouTube academy has been pretty useful but if you have any specifics you dont mind sharing, it would be helpful
  4. CaptChrome

    CaptChrome XS400 Addict

    Now we are on to something. Basically, you are going to need to find two things:
    1. The timing reference marks. On the XS400, they are under a small cover over the alternator. On some other bikes they are on the other end of the crank from the alternator.
    2. The points. On the XS400 they are at the top of the engine under a cover at one end of the camshaft. On other bikes, they are under the same cover where you have the timing reference marks.

    Once you know the location of those two things, the marks are used to set the points to open and close at the right times to cause your spark to occur at the right times. This can be done with a small battery and light or with a multi-tester with a continuity check function. But let's not get too far ahead, do a little research first to find the answers to the first two questions and then we can proceed to the next step from there.

    I will try and look around for specific info as I can, and I am sure if someone here knows the answers they will be along at some point.
  5. Thats extremely helpful. Now at least I have something to check. I was able to track down a service manual and Ill check that out to see what info that has in it.
    stillwater and CaptChrome like this.
  6. CaptChrome

    CaptChrome XS400 Addict

    The service manual will have everything you need to get it running! Look at that and come back with questions. Also be sure to report back on how it goes.

    BTW, your points are under the small round cover with three bolts on the right hand case cover and I think the timing reference marks might be accessed under the small round cover on the left side with two bolts (not positive on this though.)
    stillwater likes this.
  7. Its been a while, but I have an update and even more questions. I have done extensive research on points and how they work. I have found that this video is extremely helpful, I have to say they are pretty neat and a simple design.

    I took a break from this project because of one thing. I foolishly left a plastic funnel in the oil (opening?) and tried to crank the engine over... I felt pretty dumb. it sliced off about an inch of plastic and I had to figure out how to remove the oil pan below to retrieve it (most of it) I felt pretty defeated and needed to take a break before this broke me.
    Anyway I am back at it and tried to set the timing following this video. but it seems something is really wrong. when I turn the engine and test the Left point for continuity the plate or rotor with the fire marks is nowhere even close to where it should be. Like 1/2-3/4 of a turn
    I am thinking its the crank chain? timing chain? im not sure. Im also not sure how it could have gotten that far off.
    You guys were extremely helpful and Im hoping you can guide me through possible solutions now
  8. flea

    flea XS400 Member

    lol... welcome to the world of xs starter motors , its one of the things that yamaha persisted on getting wrong no matter which xs model , even with the xv 750 / 1000 they couldnt get it right , good thing most xs are easy to kick over , would suggest also getting on the xs650.com forum as its a lot more active and a lot of over all knowledge as a few of the members had the 500 as well , dont know if the starter rebuilds are the same but you can get the kits for the 250/400 new still or possible the xs650 rebuild kit will fit
    Daniel Moulton likes this.
  9. So another update after taking it all apart and trying to time it. The rotor behind the points plate was not locked into place and was spinning freely. After inspecting that plate I noticed that there were 2 possible ways to align it. I tried both and it seems to be much closer to the fire marks now. I will put everything back together and let you know how it goes when i try to fire it up.
    flea likes this.
  10. After timing the points as close as I could, I hooked everything back up and tried to turn it over. All I got was a massive misfire from both cylinders.


    But then I got to thinking, that maybe they were misfiring because the spark plugs didnt match up with the correct valves. I checked with my multimeter and I was correct. Somehow I got them crossed. I switched the wires and BANG, it started right up!
    This has easily been one of the greatest achievements of my life

    I havent had a hard life.

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