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Discussion in 'The Garage' started by Scotty4, Aug 15, 2020.

  1. xschris

    xschris XS400 Guru Top Contributor

    If the oil is at the correct level and on the center stand nothing will shoot out. You can adjust with the bike running. Just loosen the timing plate before you start. Another thing to make sure of is your jet needle assembly. Two things that still makes me think something is off with the bike is the very blue head pipe and the very high compression numbers. With all the motors I have tested even with low miles never got one over 155 ( cold and dry). With that high of 175 you would think it will need race fuel to run right.
    DSC03972.JPG
     
  2. xschris

    xschris XS400 Guru Top Contributor

    Just another thing to check off is to make sure the air filters are still in good shape. The foam can fall apart and get sucked in to the motor. With such a low mile bike it has to be simple, unless it's why it was parked in the first place. You did say you replaced the diaphragms with some aftermarket ones. Maybe that's part of it.
     
  3. Scotty4

    Scotty4 XS400 Enthusiast

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    I purchased the diaphragms from the recommended site on here and got the 73mm ones I believe, just checked yesterday and they're still in great shape. Needles have spring, then washer, cir clip, then plastic bushing, the annoying plastic long deal, and then snap ring.

    Air filters are new as of a few years ago, dsd purchased them as the foam was aged. My grandparents were hoarders so grandpa rode the bike a few times before it got lost in the mess of the garage. Wasn't until grandma wanted to park in the garage that he cleaned that side and gave us the bike.

    If I finally give up, I'll ride it over to Nova Motorcycles in Turners and have them show/teach me where I went wrong, but I think I can get it going with the help of the forum
     
  4. Scotty4

    Scotty4 XS400 Enthusiast

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    And as for the blue headpipe, that may be due in part to many years of start attempts with a few seconds of running too lean (plastic emmissions caps on) and not synced. The first time I ran it it was lean as well.
     
  5. Scotty4

    Scotty4 XS400 Enthusiast

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    Okay @xschris timed with light, bike was a bit retarded. Let warm up and verified LF line at idle and II at 3000. Turned screws to 3 turns out from 2.5 and readjusted idle to 1200.

    Took for a spin, hesitation is gone, nice and smooth thru the range. Just a slight jerk once getting on throttle, this normal or should I adjust the screws a tad?

    I want to buy an IR gun so I can see what my headers are doing and adjust the screws from there.
     
  6. xschris

    xschris XS400 Guru Top Contributor

    Ride it for a while. Long rides not around the block. Vacuum carbs can be a bit jerky and with your type of diaphragms maybe even more. After a long ride let the bike fully cool down then pull the plugs. Post pics. Make sure the chain is lubed and adjusted properly as that can cause a jerky feeling.
     
    Scotty4 likes this.
  7. Scotty4

    Scotty4 XS400 Enthusiast

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    Will do. Waiting on Vermont plates currently to retitle the bike so once they show up I'll go for a long cruise! Ive just been going two miles up the road then back with my Washington expired plate on it!
     
  8. Scotty4

    Scotty4 XS400 Enthusiast

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    Here are pics of left plug first, and right plug. I went full throttle in 4th and killed it before coasting to the driveway. A little lean? I'm still having to kick it 6 or so times before it fires without choke, won't start with choke. I'm at 3 turns out on screws. Need more advanced timing?
     

    Attached Files:

  9. xschris

    xschris XS400 Guru Top Contributor

    Those are not iridium plugs. If your running non-resistor caps you should use resistor plugs. Ngk bpr7es. Or bpr7eix. The end of the plug your showing is your pilot to mid range only. The mains are deep into the plug. Look up plug chops on you tube or google it.
     
    Scotty4 likes this.
  10. Scotty4

    Scotty4 XS400 Enthusiast

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    Ok, I pulled plugs again and realized my mistake. I had the oem resistor caps with the iridium plugs previously and had swapped back to stock plugs. I then changed the caps to non resistor and forgot to switch to iridiums again. Swapped the plugs and the surging is gone. Still dies when warm at idle so I purchased every pilot jet size above 42.5 (except 45 because Mikesxs was out) to try. Ill probably set the mixture screws to 2-1\2 turns and leave it then see which gives me the best there with slight adjustment.

    Right now its 4 turns out with hanging rpm and dies when warm. Almost there!!
     
  11. xschris

    xschris XS400 Guru Top Contributor

    I would only get real mikuni jets. After market ones are not made as well and can be wildly off on size and quality. Jetsrus.com has real ones.
     
    Scotty4 likes this.
  12. Scotty4

    Scotty4 XS400 Enthusiast

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    Put in the 47.5 jets, set the carbs to 2-1/2 turns, pulled out the choke and it fired first kick which it never has. Pushed in the choke moments later and it stayed idling perfect, took for a small spin and the low end stutter is gone so its going in the right direction. I let it warm up for a few minutes and it sat at 1200 perfect then slowly bogged and died. Tried adjusting out the mixture screws to 3 then 3-1/2 then 4 and it would start after a kick or two then bog and die.

    Took for another spin around the yard in 1st and 2nd and its still hanging.

    I have a 50.0, 52.5, and a 55.0. just keep stepping up???
     

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