Just doing some searching around rec.motorcycles:
> A friend and I wanted a bike so, we looked in the classified and found
> an ad for a 72' Yamaha two stroke R5 350. The bike was sitting out in
> the rain for about ten years. That didn't daunt us so we it rebuilt
> anyway. We replaced the lower end, had the pistons rebored and bought a
> new battery and sparks. The bike started up then quit.
Been there. Seems like you have a pretty good start on making the bike
a runner. We'll get to the electrical problem in a minute. First you
need to take care of some other areas before they get to be real
If you don't have one already get a good manual, Clymer or Yamaha.
You made no mention of the fuel system. Here you need to:
1. Empty the tank, remove the petcock and clean that sucker out. If
there is rust buy a tank coating kit with an acid wash. Kreem makes an
2. Empty and clean the oil reservoir. Its plastic so it won't rust.
Fill with a good quality premix. Golden Spectro or Yammalube.
These items are important because they not only feed fuel, but
lubrication to the engine. It is a good idea to add inline filters to
> I took it into
> the shop and they dialed in the points. I took it home, it ran once or
> twice. Then it doesn't start again. In fact, it drains the battery. I
> know the problem is not the starter because it has a kick starter. I
> tried to push start it, no luck. I don't know what to do. And I don't
> want to spend a fortune to have a mechanic look at it. When it runs it's
> a really great bike to ride.
Sounds like it is not charging. First get a battery charger. They make
some inexpensive units. You don't want anything that charges over 1 amp
or you may harm the battery. I would recommend getting a "Battery
They run about $45 dollars but are excellent units that can be used to
keep any small battery at full charge without worry.
With the battery at full charge start the bike and hag a voltmeter
across the battery. It should read about 14 volts with the engine
running about 3,000 rpm. If not , get to checking. Since this thing
has set outside so long in the rain I would undo all electrical
connections, clean them and stick them back together using a dielectric
Recharge the battery and restart the engine. Still no 14 volts? (it
will read 12 volts if not charging). You may have a problem in the
charging system itself. Could very well be the voltage regulator.
Follow the manual in trouble shooting the charging system.
DO NOT ride the bike unless it is charging. If the battery gets low the
ignition system can not do its job and the engine will detonate or eat
its own pistons. Trust me on this one. It happened to me.