1982 Yamaha 650 - no start

Discussion in 'Motorbike Technical Discussion' started by dmschuler, Jul 10, 2008.

  1. dmschuler

    dmschuler Guest

    Good Evening!

    My nephew called me last night. The bike he just bought won't start.
    I'm going to try to help him get it going again, and thought I'd do a
    little research first. I've read the posts related to no start
    conditions, but I thought I'd also post a message here too. One thing
    I know I'm going to need is an electrical diagram - does any one have
    one that they'd be willing to share, or is this something that only
    comes with the shop manual?

    He said it was having electrical problems. He mentioned that it got
    wet, and hasn't started since. Electric start won't work at all. Kick
    start yields just a sputter.

    My plan is to do a complete electrical inspection - grounds, fuses,
    look for corrosion, etc. One of the posts I've read indicated that
    there could be corrosion in the iginition switch - can that be taken
    apart? Once I'm satisfied that all connections are solid, I'll start
    with spark test, fuel flow (gravity feed?), other basic checks, etc.

    Is there anything these bikes are notorious for?

    dmschuler, Jul 10, 2008
    1. Advertisements

  2. dmschuler

    . Guest

    If the battery is old and sulfated, it may not produce enough voltage
    operate the transistorized ignition system. Transistor ignitions are
    dead stone reliable, they either work, or they don't.
    Most newbies don't know how to "choke" a motorcycle with constant
    vacuum carburetors. Since there is NO flat choke plate like a car has,
    you have to leave the twist grip alone when starting. Just pull the
    "choke" knob or move the "choke" lever to the full ON position and
    crank the engine.
    Usually not. But, if you work the ignition switch through all of its
    positions several times, it should clean the contacts itself.
    Yes, most motorcycles of that era had a gravity feed system. Many had
    a vacuum-operated automatic shutoff petcock. If you see the letters
    PRI by the petcock knob, that's the PRIME position, and it will fill
    up the carbs even if the engine isn't running yet.
    Yes, they were notorious for being bland and boring, so they were
    "Universal Japanese Motorcycles".

    BTW, does he have the twin or the 4-cylinder 650?
    ., Jul 10, 2008
    1. Advertisements

  3. dmschuler

    Who Me? Guest

    Engines in general are notorious for not running (good) if the battery is
    I suggest you test that........and the main connections .......before you
    waste a lot of time on other things.

    Except for the safety interlocks, kill, clutch, neutral, side-stand, a bike
    engine is really no different than a small car or a big lawn mower.
    Who Me?, Jul 10, 2008
  4. dmschuler

    dmschuler Guest

    Thanks for the replies. I'll start with the items you both suggested!

    dmschuler, Jul 10, 2008
  5. dmschuler

    dmschuler Guest

    lol! He has the twin.
    dmschuler, Jul 10, 2008
  6. dmschuler

    . Guest

    It really helps us if you state in your very first message which model
    you're having problems with.

    The XS650 started out as a very simple machine, apparently a sort of
    Japanese Triumph twin, but actually based upon a defunct German

    Then the XS650 began to get weirder as various electrical interlocking
    gizmos were added...

    Go to this link and look at the typically weird electrical components
    that only Yamaha would use:


    Look at Electrical 1 and Electrical II.

    Like, there is a side stand switch *and* a side stand switch relay to
    complicate the electrical system. There is a relay that seems to
    defeat the starter. There is also something called a "reserve lighting

    If you look at the AC generator, you'll see that it is a brush type
    alternator. There is a Hall Effect sensor on that drawing. It triggers
    the transistor ignition unit.
    ., Jul 10, 2008
  7. Ignore Krusty as he really doesn't have any knowledge of these bikes
    beyond what he can glean from poring over a schematic or Googling.

    They're incredibly tough bikes. The engine is as strong as anything.
    The weak point is the electric start, or to be specific, the starter
    clutch. A lot of people junk the e/s, and you can buy a blanking plate
    that fits over the hole.

    Anyway, if it's been standing, then the fuel will have gone off and
    partially blocked the carbs. PITA, but fixable. If it's really, really
    badly gunged up, then ultrasonic cleaning is really the only sure fix.
    Assuming that it hasn't been standing, and has new fuel and a new
    battery and new spark plugs: are you getting a spark? If it's
    sputtering, that suggests that there's some form of ignition
    happening. Generally, though, electronic ignition systems either work
    or they don't. There's no in-between. Earlier models of the XS650 had
    contact breaker points, and different rules apply there.

    If there's no spark, then it could be the ignition switch or the kill
    switch. It's more likely to be corroded connectors in the loom,
    however. But if it got wet, and was running fine beforehand, I'd
    expect it to run after being dried out. If the switch is corroded,
    then turning it on and off a few times won't cure it properly,
    whatever Krusty says. Think: if turning it on and off got rid of
    corrosion, well, it would never get the chance to corrode ever, would

    I've just had to strip down an ignition switch for a 1977 Honda. I
    cleaned it thoroughly with very fine wet & dry paper and contact
    cleaner, bent all the little springs and contact points a fraction so
    they made better contact, reassembled, and it was perfect. Top tip:
    dismantle it inside a large transparent plastic bag, because these
    switches are full of pingfuckits, and when you pull them apart, tiny
    springs and ball bearings can fly everywhere. Same goes for the kill
    switch, although it's easier just to bypass this.

    If it's totally dead, bypass the sidestand ignition cut-out switch.
    These bloody things always give trouble when they get older. I've just
    had to bypass the one on my 1991 XT600E dirt bike.

    Fuel flow is gravity feed, so no whahala there.

    Seriously, it's a very simple basic bike, and the basic checks should
    soon isolate the problem.

    Mechanically, as I said, no weaknesses. Camchain adjustment is 100%
    manual, and must be done properly. Also, be warned that it has not
    one, but two oil drain plugs, and two oil filters: one in the sump,
    and one behind the circular cover on the right-hand side of the
    engine. These are both washable mesh filters. The big one in the sump
    has a reputation for breaking up, though.

    Finally, Yamaha always recommended 20/50 oil for the 650 twin, not the
    much more common 10/40.

    They are wonderful bikes. I've owned (counts on fingers) four, and I'm
    sure I'll have another one day.
    [email protected], Jul 10, 2008
  8. dmschuler

    dmschuler Guest

    well, I didn't realize there was more than one option for the 650.
    He's had the bike for about three weeks now, and I hadn't seen it
    until tonight. Had I known there was a twin and a 4 cylinder option, I
    would have specified that.

    Just got home from his house. The battery was completely dead. Very
    low water. After charging the battery for a bit, I was able to get it
    started. I took it for a short ride, and it is runs very strong. He's
    buying a new battery tomorrow. I'll be walking him through the basics
    this weekend, and the suggestions and pointers offered here will
    definitely help!

    Now my next challenge is to get one for myself, but I'll have to work
    on the wife first!

    Thanks again everyone!

    dmschuler, Jul 11, 2008
  9. dmschuler

    Who Me? Guest

    Oh just go for it. She'll get over it........or she won't. Either way you
    win! ;-)
    Who Me?, Jul 11, 2008
  10. dmschuler

    dmschuler Guest

    I like your way of thinking!
    dmschuler, Jul 11, 2008
  11. It's invariably the simple things that stop an engine working....
    The Older Gentleman, Jul 11, 2008
  12. dmschuler

    . Guest

    Tell him to buy a maintenance-free battery. It won't need water for
    six or seven years.
    ., Jul 11, 2008
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.