91 r100 GS PD not starting

[davidp]

hey all,
got home from a ride yesterday and left the key in my bike in the off position for a couple hours, later that night when i went to move the bike it barely turned over, but started, i rode about 50 feet and it died and wouldn't turn over, like the battery was dead, but none of the lights were dim. This morning i figured id jumpstart it and take it for a ride to recharge the battery, but after about 10-15 minutes of charging from the car it had the same dead battery symptoms when i tried to start it, but all the lights were their normal brightness (not like when the battery is actually dead). if its not the battery what could be causing this? bad starter motor?
any help would be greatly appreciated.
thanks

[lmo1131]

david,

Standard question: how old is the battery? is it low on electrolyte (if it's not a sealed battery). For whatever reason, it's not holding a charge.

Just because the lights are "bright" doesn't mean the battery is "good". It takes signficantly more amperage to spin over the starter than it does to illuminate a 4w bulb.

My guess is; it's the battery. Can you beg, barrow, or st.. .. get a loaner battery to test this idea?

[widebmw]

Bad starter relay

[davidp]

those are good points, however i tried to start it while still connected to the car which would "bypass" the battery and that didn't work. also I've been riding the bike all for the past two seasons and have never had a problem, the battery never even seemed "weak" and then last night it just died (or something happened). trying to find a different battery to test is a good idea, ill see if i could scrounge one up.
thanks

[davidp]

how could do i check the starter relay? it turns over, but just barely

[lmo1131]

the next thing(s) to check for would be loose cable connections and/or corroded cable terminal(s) (ground cable to batt.; heavy red cable to starter; etc.)

[widebmw]

If it were the starter relay it would not turn over at all, back to the battery.

[davidp]

Ive checked ground to battery and its top notch, not sure about batt to starter. the thing that's really getting me is that I've been riding all summer without any hint of a problem and then i get home from a ride, bike sits for 4-6 hours with the key in but off and BAM won't start.

[lmo1131]

the thing that's really getting me is that I've been riding all summer without any hint of a problem and then i get home from a ride, bike sits for 4-6 hours with the key in but off and BAM won't start.

... dollar to a doughnut, it's battery gremlins.


So, mmm.... how old did you say that battery was?

[davidp]

damn gremlins... yeah i don't know how old the battery is, it has it was in the bike when i got it 2 years ago. when i tried jumpstarting it i connected the jumper cables to battery terminals and the leads that attach to them from the starter and ground and it still wouldn't turn. when connect the jumpers like the doesnt it bypass the battery?

[mneblett]

I also would tend to suspect the battery, but I will toss out another possibility: A Valeo starter motor with at least one of the glued-on magnets having come loose. Usually, this will jam the starter motor completely, but there is the possibility that a just-coming-loose magnet may be only as yet causing excessing drag on the rotor.

My first test: Put a voltmeter across the battery and observe the voltage as you push the starter button. If it drops from ~12.5V to 10V or less, the battery has too little capacity left to supply a starter motor.

My second test, if the battery is good: remove the starter from the bike, clamp it down so it can't jump around, and apply 12V from a known-good battery directly to the starter motor terminals to see whether it rotates normally, or is slow/dragging.

[lmo1131]

+1 Mark

If this was an old Chevy truck I'd just reach in there with a beat up pair of pliers and "short" across the starter terminals with them ... if it was a beat up old truck, that is

Make sure you disconnect the battery ground cable before you pull the starter out.

[lkchris]

On these bikes the fact that the lights come on is meaningless as to whether the battery is in any condition to start the bike.

99.9% of the time your problem is a bad battery ... only solved by installing a new battery.

[davidp]

thanks for all the help guys! I'm currently away but will try to make time to dig in when I'm home. ill report back soon!

[davidp]

hey everybody, just took apart the bike and found that where the wire from the starter solenoid connects to the starter motor its all melty and smokes when you try and turn the bike over. its pretty much not really connected.. so the problem is that theres not enough power getting to the starter motor. does anyone know how to get the motor out? there are two bolts but i cant think of a tool that would fit in there to loosen them.