1982 Yamaha 650 - no start

 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?

Thanks!
Doug

 On Jul 9, 5:22�pm, dmschu...@gmail.com wrote:


If the battery is old and sulfated, it may not produce enough voltage
to
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
called
"Universal Japanese Motorcycles".

BTW, does he have the twin or the 4-cylinder 650?

 
lol! He has the twin.

 On Jul 9, 6:29�pm, dmschu...@gmail.com wrote:


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
design.

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:

http://www.powersportspro.com/pages/parts/viewbybrand/default.aspx

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
unit".

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.

 


Engines in general are notorious for not running (good) if the battery is
dead.
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.