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Doesn't want to start, dies out right after.

Discussion in 'The Garage' started by buztabuzt, Jun 11, 2019.

  1. Have now cleaned up wires, brakes, clutch. Been into the carbs a few times now and not afraid of doing it again if needed. I solved the float sticking so it no longer dumps gas out the air filter (needle tang needed slight bend back into form to allow easy plunging)... small victory.

    Wanted to start tuning but appears she's not ready. Still resistant to starting. Fired up once or twice on choke but died out within 3 secs. Sparking fine. Right plug looked normal, perhaps slightly wet from gas. Left plug looked blackish from carbon, probably from when I had it temporarily running a month ago but the carb was flooding it.

    Do I try going in and out with mix screws? I started 3-3.5 turns out as suggested. It's just very resistant on the e-start. As an aside, the kick start now moves without resistance... All I can guess is i mucked it up when adjusting clutch?
    Last edited: Jun 11, 2019
  2. I should reiterate the punter who had my bike previously drilled holes in the exhaust so perhaps I need to adjust mixture screws for that?
  3. SoulMan

    SoulMan XS400 Addict

    I would assume its carb relate. Clean the carbs again paying attention to the small passage that's in the bottom of the float bowl. I poke it with a small guitar string and spray carb cleaner in it and blow it out with the air compressor.
  4. xschris

    xschris a lifestyle not a trend Top Contributor

    Start with some new plugs. Pilot mix screws 2.5-3 if you have stock air filters and intake. Holes in the stock mufflers are never good. What's the compression on the motor? Non-ethanol gas? ethanol gas that sits for even a short amount of time can gel on the bottom of a tank unless treated with something that prevents it.
  5. Non ethanol and I added stabil and inline filter. Compression around 145. Agreed - I will have the holes welded in the muffler but was hoping I could ride it to a shop to do so.

    I'll get new plugs for a trial. Also, battery isn't great. I have started it with this battery multiple times but doesn't seem easy. May just replace to rule it out. Can trickle up to 12.65 or so. Dwindles to 12.5v. Once I try to e start once it won't recover much past 12.3V unless it's charged higher (trickle or stator)
  6. Fired away! Did small tweaking with mix screws but big thing was adding in New non iridium plugs. Once it is reliable I'll try iridium again. Pic is after 2 minutes and after 1 minute so not enough to get a good read I don't think

    The concern remains that it still smokes from header pipes / exhaust wrap when gets up to temp - I think / hope it's the wrap and not something else but hard to tell. Obnoxiously loud with drilled exhaust.

    Might try to get a short ride in tomorrow to see how it reacts. Idle hung a lot at first but second time I started I lowered idle screw and enriched mix out 1.5 turns further it was better. Probably around 4.5 out now but not certain since I've tinkered so much I should prob reset it. Maybe after test run. Passed carb cleaner spray test

    Attached Files:

  7. SoulMan

    SoulMan XS400 Addict

    I think if you want to use iridium plugs you need non-resistor caps.

    p.s. your bike looks nice! :)
  8. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Theres no point in making adjustments when you arent actually riding the bike. Go for a 20 mile ride. Keep the idle mix at 2.5-3 turns out and dont mess with it yet.

    Plugs look wet.

    Dont rush to change settings and try new plugs. Tuning can take a long time. Get your bike set up and leave it alone. Change your jets or raise the needle when you need to and thats it. Ive ridden my bike for up to a week at times before jetting again.

    It took me probably 3 months before I had a decently tuned bike. Theres a lot of settings that will work and improper ways of compensating.. You do not want to be compensating.
    buztabuzt likes this.
  9. xschris

    xschris a lifestyle not a trend Top Contributor

    The bike needs to be run at highway speeds to get good tests. 4 turns out for pilot mix screws is max any more and you need to up the jets. Your plugs look like the pilots are too rich already. Fix your mufflers and then start the tuning.
    buztabuzt likes this.
  10. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Also, exhaust wrap will smoke for a while. Youre supposed to apply it wet and let it shrink.

    I wrapped an old exhaust for my mini bike and it smoked for days, and ruined the pipe. To be fair, i was riding the bike in swamps and wet muddy areas.

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