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My 2 steps forward 1 step back bike build

Discussion in 'The Garage' started by short1, Jun 24, 2018.

  1. xschris

    xschris XS400 Guru Top Contributor

    You need to re-sync after valve adjustment. Do it with a warm motor and at idle. Oh the joys of running a non stock setup with these bikes.
     
  2. short1

    short1 XS400 Addict

    I threw in 47.5 pilots, replaced the passage plugs and resynced the carbs. Starts and idles great, revs right through no stumbling or hanging. Just took it for a ride...starts out good but midrange is a little jerky until full throttle with the rpms up then it smooths out. Im guessing needle needs to be shimmed? To adjust the non-adjustable needle I would put a washer in before the needle correct? The only notch on it is what holds the clip in so idk how else I would do it. What thickness washers should I use? Not alot of info for this type...Also it was about 250° at the head after ride
     
  3. xschris

    xschris XS400 Guru Top Contributor

    You would shim under the clip that holds the needle. That would make it richer by raising the needle. I would look for a shim that is the thickness of the groove. What do the plugs look like? 250 is kind of cold after a good long ride. 265-285 is a bit better. The plug read will tell you what needs to be adjusted. Look up plug chops.
     
  4. short1

    short1 XS400 Addict

    So the shim would just slide on up to the clip, or it would be between the clip and plastic ring? Sorry I'm a visual learner lol. It was only about 5 minute ride on side streets to see how it pulled, still waiting on plate
     
  5. xschris

    xschris XS400 Guru Top Contributor

    Yes between the clip and the plastic ring. You need to run at highway speeds for a good length of time in order to clean to plugs and get the bike fully warm. Short rides and lots of idle time is the worst thing for these bikes.
     
    buztabuzt likes this.
  6. short1

    short1 XS400 Addict

    So the c-clip will still go on the needle even if not on the notch? They're new plugs too. I know it's not great but I didn't let it idle much and like I said it's not legal yet so didn't want to go far...I'll try tonight to see if I can figure out the shims
     
  7. xschris

    xschris XS400 Guru Top Contributor

    Leave the c-clip alone. Pull off the plastic part then slide the shim on. Then put the plastic part back on.
     
  8. short1

    short1 XS400 Addict

    Ok, got it, I thought the clip held the plastic thing on thats why i was confused..makes way more sense after realizing it slide off the other way. Start with 1 shim at a time I suppose?
     
  9. xschris

    xschris XS400 Guru Top Contributor

    Yes small bits at a time.
     
  10. short1

    short1 XS400 Addict

    Been awhile since I've updated. Since its getting nice out i'm trying to get things dialed in. I've replaced the throttle shaft seals and checked for air leaks, all sealed up finally! It's still jerky under load and I can't figure it out. I've got 147.5 mains 47.5 pilots and 1 shim on the needle, mixture screw is out 4 turns. Carbs are synced with a homemade manometer. It's starts right up on choke and after a few seconds will idle and rev fine without. I've tried little adjustments on the carb, if I put the mix screw in or out half a turn it idles rough and either bogs or hangs depending which way. I added a 2nd shim on the needle and it was way rich, removed the shims and it didnt want to run. So i went back to the above settings. No matter what i do it doesn't change the jerkiness under load. Tonight I put in fresh plugs and went for about a 15 mile ride with opportunity to get the rpms up. It was about the same jerkiness though sometimes above 4500rpm it would take off like a rocket, but not every time. I'm kind of at a loss as to where to go next...pulled the plugs right after the ride, left to right side respectively
    20190425_193819.jpg 20190425_193828.jpg
     
  11. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    I dont think you have enough time on the plugs, but you say that the bike stumbles, so your setup is wrong anyways..

    Plugs look like theyre washed..? From tunning too rich perhaps. Something is not even between the 2 cylinders. Toming too advanced perhaps.

    Id get all settings stock, and try different main jets and get your full throttle first before moving on. You must be able to go full throttle at around 5k rpm all the way to redline with no stumble.
     
  12. short1

    short1 XS400 Addict

    Since you mentioned something of it, and trying to bring it all to stock settings seems like a huge undertaking right now, I decided to look into the timing side of things. Should there be screws holding this down? It's kind of flopping around..i don't feel like it's supposed to do that...
    20190426_124816.jpg
     
  13. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Yes there should be a screw(2) on the top and bottom, they hold the timing unit secured and clocked where you set it. If you turn the timing unit clockwise, you will advance the timing, counter turning will retard.
     
  14. short1

    short1 XS400 Addict

    If you look close at that pic you can see a crescent on the edge where it was tightened down originally, I just set it there to see how it went. When i started it, it sounded different...Just went for a nice long ride and it's running great! Pulls smooth in all gears and there's power anytime I give it throttle, no hesitation or stumble, no pops or backfires. Unbelievable oversight that gave me so much grief! Thanks for all your help guys, seriously grateful I suppose I should verify the timing, make sure the valves are adjusted and resync the carbs
     
    buztabuzt likes this.
  15. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    You will need a timing light, not sure if theres a way to use a test light. I use the test light to get everything close, then the timing light for the final setting. My bike has points ignition so its a bit more involved.

    Valves
    Carb sync
    Timing

    Thats the order I go.

    Make sure you dont have it set too advanced. That can cause major problems. Too retarded and the bike wont run right, or at all in low rpms.
     
  16. short1

    short1 XS400 Addict

    Got a question about the clutch...I just can't find that sweet spot in the friction zone I've been riding my bike every chance I get and I can't seem to get comfortable with the clutch. I've adjusted it per manual instructions, there's a little free play in the handle before it pulls, it engages/disengages about midway. Taking off in 1st it just seems it's either on or off like a switch rather than easing into it. I've been driving manual trans including bikes for almost 30 years and I just can't seem to get a handle on this one. Is this how these bikes are or is there something I should be looking into? Love riding it but this is driving me nuts
     
  17. xschris

    xschris XS400 Guru Top Contributor

    That's just how these are for the most part. Not going to act like a car remember these are wet clutches and a very simple design.
     
  18. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Our clutches are sloppy like dirt bike clutches. My clutch handle is a bit floppy. I keep it like that purposely. The clutch should really only engage at the last bit before letting it go.
     
  19. short1

    short1 XS400 Addict

    I guess I'll deal with it and try to get accustomed, thanks guys
     

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