78 Yamaha DT 400B start up

Discussion in '2 smokers' started by Imflyinn, Jun 1, 2013.

  1. Imflyinn

    Imflyinn Adventurer

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    Hi everybody,
    I'm new here and to motorcycles. I'm a college engineering student and have very little experience with motorcycles. I have had this bike sitting in my grandfather's basement and have just gotten the ok to finally get it fixed up. It was last ridden in 1980, and is in great condition for the age. It was put away the right way, but may or may not have been started up once between now and then. It is all together and I have the instruction manual for the bike. Can anyone give me a list or advice for everything that I need to do in order to get it ready to get fired up and ridden, or have a link to a site that would tell me everything that I need to know?
    [​IMG]
    #1
  2. joexr

    joexr Banned

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    Is it dual shock or monoshock? B would be a 1975 dual shock and a 1978 would be an E. Hopefully the carb and gas tank were drained. Drain and refill the oil tank and change the oil in the transmission.
    #2
  3. Imflyinn

    Imflyinn Adventurer

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    The manual mentions a rear shock so I'm assuming it must be a dual shock? Thanks for clarifying the year, I wasn't positive what year it was, it is a B so it must be a 75. There is a 50/50 chance that it was drained. It was stored without the gas tank most of the time, I'm not sure if everything was put away the way it should. I know it was put away correctly, but may have been started for just a minute since then about 20 years ago then not completely drained. There was a small amount of oil under the bike, should I go through the engine and change out o rings before I try to start it? I still need to take the glow plug out to make sure the engine isn't seized which it shouldn't be. Step one for me is getting it home, I may need to walk it over a quarter mile home before I can start on it.
    #3
  4. joexr

    joexr Banned

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    Are the fenders silver or yellow?
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  5. Imflyinn

    Imflyinn Adventurer

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    Silver
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  6. joexr

    joexr Banned

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    '75 then. Get a new spark plug and make sure there's oil in the tank and transmission. 2-cycle oil in the oil tank and 4- cycle in the transmission. Should be a filler cap on the transmission , I think with a dipstick. The oil tank has a sight-glass to tell when to add. This gets filled almost to the top and is slowly used up. I'd try to get it running first , then see what was leaking.
    #6
  7. Imflyinn

    Imflyinn Adventurer

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    Thank you, I was off by a couple years. I am hoping to pick up the bike around Tuesday and start working on it and learning more about it, and hopefully learning to ride on it in a few weeks.
    #7
  8. joexr

    joexr Banned

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    Check out Clymer and Haynes to see if either still has service manuals available.
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  9. Imflyinn

    Imflyinn Adventurer

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    Are they copies of the original? I actually have the original manual that came with the bike.
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  10. joexr

    joexr Banned

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    Do you have the service manual or the owners manual? Just looked it up , the Clymer is still available.
    #10
  11. lrutt

    lrutt SILENCE.....i kill you

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    I think I'd do a little premix as well first start in a long time. Can't hurt.

    Also verify the oil pump is bled and no air bubbles. Just to make sure. Once running you can do a quick test to make sure it's pumping.

    and make sure the air filter element has not deterioriated. If it's foam lots of times it will just crumble. Do't want that in ur motor. Either make or buy a replacement but avoide going to a KN IMO.

    I also think I'd clean the carb out anyhow. Is the tank rusty or shiny? if rusty, put an inline filter in then do a cleanup on the tank. Either evaporust, vinegar, electrolysis, whatever.

    I tend to take a very conservative approach to starting a long dormant motor. Sure you can just go boot it to life but you can also greatly reduce it's life expectancy if things aren't all right.

    Do it right or do it over. BTW, what's your location?? in case you need some help.
    #11
  12. joexr

    joexr Banned

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    Good points , especially on the airfilter.
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  13. Imflyinn

    Imflyinn Adventurer

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    It looks like the owner's manual, I will have to look around to see if I can find a service manual laying around, if not I will definitely go for the Clymer manual. I will definitely check out the carb and filter as soon as I can. I live in Massachusetts, and it is raining now so I can't pick it up today, hopefully tomorrow. My dad will be around when I get it home and he knows the bike inside and out, but this is something I would like to do without his help until start up time. If I do need to buy parts for it do I need to buy original parts or will newer parts fit? Unfortunately my local shop with the owner who originally sold the bike closed so I will need to find a new place, but I am very short on cash to begin with so I would like to keep it as cheap as possible.
    #13
  14. Shocktower

    Shocktower Long timer

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    One of the first things is, main seals, they rot and you will know after it seizes then the carb and make sure the air boot is not cracked the rest is good times :clap
    #14
  15. Imflyinn

    Imflyinn Adventurer

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    Just a quick update, got the bike home today. Got stopped on the way with it by a guy who said a similar one was his first bike and how it would start up right away for sure. I can't start looking at it tomorrow, but hopefully Thursday night I will be able to start messing with it.
    #15
  16. gloud

    gloud Been here awhile

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    Do the main seals unless they have been replaced in the last few years they are cheap and only take a few hours to do. it will save you $$$ in the end.
    #16
  17. Imflyinn

    Imflyinn Adventurer

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    Got into the bike today, and I will replace the main seals for sure. The engine is in perfect shape but the carb is frozen. I have PB Blaster and WD-40 on it now, is there any way to get it unfrozen or will I need to buy a new one?
    #17
  18. joexr

    joexr Banned

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    If you can , pullit out so you can work on it. Will the top unscrew?
    #18
  19. Imflyinn

    Imflyinn Adventurer

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    The top will unscrew but not come off completely
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  20. Imflyinn

    Imflyinn Adventurer

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    Right now it is only connected by the top piece. I took a piece of a clothes hanger and have the carb suspended upside down from the handle bars so hopefully the WD-40 will get in there
    #20