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Hi all, I need help 1977 not starting

Discussion in 'The Garage' started by Niro, Nov 3, 2019.

  1. Niro

    Niro XS400 Enthusiast

    they sounded strange to me too, I planed on looking at them again. Oil is valvoline 20/50 wet clutch, and seems full. Any suggestions for a more permanent bond and seal for the manifold barb?
    I’m going to pick up the throttle spring and new vacuum hose from the dealer tomorrow.
     
  2. xschris

    xschris a lifestyle not a trend Top Contributor

    Some high temp epoxy will work. Are those manifolds from yamaha? I never had a barb get loose on any of the ones I have used.
     
  3. Niro

    Niro XS400 Enthusiast

    Got them with the bike, not sure if they are yamaha
     
  4. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Every set of aftermarket boots Ive had, the barbs always come loose. When the bike is hot they will be loose enough to pull out with your fingers.

    I use a pair of needle nose pliers to hold the barb while I put the caps back on.
     
  5. Niro

    Niro XS400 Enthusiast

    Barb is bonded with jb weld, works fine for now, doesn't seem to leak.
    I did the valves again, broke the valve cover plug, had to wait for a new one
    got the throttle spring for the carb
    replaced the vacuum hose


    It seems to run nicer, a little quieter, fewer vibrations, and maybe a better pull in the mid-range. I did the valves 3 times, the last time i was using a fixed wrench (that i didn't have the first couple of times) and not a ratchet, i feel like the ratchet didn't allow me to stop exactly on the spot (needing to change directions on the ratchet to hold the crank from wanting to spin).

    We had a nice weekend high 60s low 70s, so i had 0 starting issues after doing the valves and adjusting the idle and air screws. This morning was a little cold, about 45 degrees, it didn't want to start, not even with starting fluid. Is this going to be a summer-only bike? or not a morning bike?

    The right side was a little richer than the left, I am going to look into it.

    I think i am also going to check what its like with smaller jets, ill go back to 142.5 main, and see how it feels
     
  6. xschris

    xschris a lifestyle not a trend Top Contributor

    Always re-sync the carbs with manometer after adjusting valves.
     
  7. Niro

    Niro XS400 Enthusiast

    I am still having a hard time starting it in the cold, it starts, but it takes some work (starting fluid and many kicks). When it's warm, it starts fine, when warmed up it starts on the first kick.

    It seems like my main issue is cold starts. When it starts, it rides nice, pulls strong and maintains a somewhat consistent idle speed, not sure if it is masking other issues, but i hear some of you guys saying it starts on the first kick cold or warm and I want that :)

    I changed the mains to 142.5 (from 145), it seems like i was running a little rich, synced the carbs, the bike felt great, i could idle it on 1000-1500 and it sounded good. Rode great (no freeway tho), ill do the spark plugs reading after riding it a little more and see what's going on there. (no change on the cold starts)

    My choke dust seals are loose, got them new but i guess its the wrong part. Do they have any effect on the vacuum? are they just dust sealers?

    Also, I keep reading about the mix screw washers/selas, from what i was reading, I do not have them and do not need them, could anyone confirm that some models do not have them?

    Last, my mix screws springs look too short, at 3 turns they almost have no pressure on the screw, at 3.5 they are loose. Could i just stretch them a little ?

    Thanks again
    Nir
     
  8. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Difficulty start in cold weather is the nature of the beast. It can run crappy until its warmed up. This is what old machines do, its all they do. You need to prime the bike before you start it every time unless the bike is hot. Put the choke on and kick it 3 times and then turn the ignition on and start it.
     
  9. Big Al

    Big Al XS400 Member

    I used to get that on a CB650 I had. I synced the carbs and replaced the tired old coils. Sometimes it's two or three little things going on at the same time taking you down the rabbit hole. Have you had any recent carb work?
     
  10. Big Al

    Big Al XS400 Member

     
  11. Big Al

    Big Al XS400 Member

    Hey Niro, I'm going through almost the exact same problem right now. I got a stock air box though. One thing that I learned about pod filters is that you should go up about 15 stages from the stock jets. Also one cylinder will be your base cylinder with primary coil. That cylinder is typically jetted a couple stages higher than your secondary cylinder. Reason being is that the primary requires a bit more fuel for intial start up. The air pods reduces all resistance to your carbs giving you a ton more air than what's required, hence needing bigger jets to off balance. You will likely have to experiment with different stages of jets to get 'er bang on. Hard learned experience
     
  12. Niro

    Niro XS400 Enthusiast

    Priming it helps, starting in the cold is slowly getting better, or the weather is getting warmer lol
     
  13. Niro

    Niro XS400 Enthusiast

    Hi Big Al
    Thank you for your feedback. Im pretty happy with how it rides, I dont have any hiccups or dead spots on the throttle, it still needs fine-tuning, but works well for a 43 year old :)
    my main issue is cold starting, I am experimenting with jets now.
    Thanks
     

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