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schneeman

Starter engages when i reconnect battery....on a K1200RS

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schneeman

I konw i know wrong forum, but i know this place a bit and know we have some very experienced friends here, and the issue is i think rather more general than just K1200RS. Or maybe it isn't, dunno, that's why i am asking. I won't have time to take a look at the bike for next few dyas, so i thought i can gather opinions+advice in the meantime. Bike is from the same era as my RT, similar technology, year 2000.

As title says, starter engages when i reconnect negative battery terminal. DUe to my own stupidity bike died on me completely upon startup attempt, that was the battery's last throw and when i took it out , there was no measurable voltage on it. For some reason forgot KRS needs juice over winter as well :S , especially since i have alarm on it. I think the key to this is that the bike actually died completely while starter was turning. So now a couple of weeks later, battery back up to specs, i connect the positive cable (btw yes i am sure it is the right polarity), i connect negative bundle, sparks, starter engages. No key in ignition, no matter if on off or lock position, kill switch on "off", all fuses pulled, still same thing. So i am assuming something welded shut on the starter circuitry somewhere, so the plan is to take the panel again and check it out. First hope i didn't fry anything, i tried it a few times disconnecting more fuses etc in the process, so tried maybe 4 times very shortly, just to see if i get the starter effect again. I know that was rather stupid, should stop more and think. I sort of remember vaguely reading something about weird things happening when a battery runs out like that, but not sure.

Is this something that is a know effect and happens when your vehicle dies like that with starter on ? Any info appreciated, thanks a lot !

 

Edited by schneeman

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dirtrider

Evening schneeman

 

Might be as simple as the starter drive gear is still meshed in the flywheel teeth.

 

There is a return spring in the starter solenoid but that might not be enough if the starter stalled under load.

 

Try connecting the battery & allowing it to crank a bit.

 

Let it crank a few engine turn-overs then IF it doesn't quit on it's own disconnect the battery.

 

If the above doesn't help then leave the battery disconnected--then get some warm bodies to help you, then put the trans in high gear & push the bike a short ways (that should allow the engine to forward drive the starter drive/&/starter & hopefully drive the starter drive out of mesh with the flywheel)

 

If that doesn't help, then next try (temporarily) hooking the battery up & allowing the engine to crank, then turn the key on to hopefully allow the engine to fire up that s-h-o-u-l-d allow the engine to drive the starter drive out of engagement with the flywheel therefore opening the solenoid internal contacts & stopping the starter from powering itself.

 

Unlike older starter systems your "K" bike doesn't have a Bendix type system but instead uses the more modern starter drive pulled into engagement by a pivoting fork from the starter solenoid. Inside that starter solenoid is a heavy duty contact switch that actually makes contact to power starter so IF the starter drive stays engaged with the flywheel that contact switch can stay closed & power the starter.

 

I'm pretty sure that IF you can get the engine to momentarily back drive the starter that should kick the starter drive back & open the solenoid internal contact switch to stop the starter from cranking on it's own.

 

 

Edited by dirtrider

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n5926g

Not sure if your,s is like my 1100RT,but MY starter has two LARGE wires connected to it,and one small wire.The small one controls the contacts in the starter "bendix'...if your,s is like mine,try unplugging that small wire,and see if it does the trick.If so,the contacts in the "bendix" assy are toast.

The term "bendix" is old school,but basically is an internal relay that activates the high current contacts that energize the starter coil.

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kioolt

I'm not sure about the K1200RS's but the K75's, K100's and K1100's do not have a bendix on the starter. You can check this by checking to see if there is only one wire on the starter. If there is only one wire on the starter then there is no bendix. It is common for K100's, K75's and K1100's to have the situation that you have if someone tried to start them with a week battery. It causes the starter relay contacts to weld or stick together. It doesn't matter about the key being on or off or which fuses you pull. You can often unstick them by tapping on it. It is located in the relay box under the tank. It will be the relay with the big wires on it.

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schneeman

thank you all very much !

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Tri750

The big K bikes will fry the modern solid state starter relay if you attempt to start the bike with a low battery and are persistent in getting it to start when the voltage is too low.

The exact symptom you describe happens.

 

Once the damage is done, The key can be in your pocket and when you touch the cable to battery, it cranks.

 

The early point type relays could be broken free as mentioned above. Solid state relays just short.

 

There is a retrofit relay kit 61357663945 that will both relocate the relay and prevent this from happening again. (Supposedly)

 

If you continue to let it crank, or of you've done it a lot trying to jar the starter loose, you'll burn the starter up too. The starter is not the problem.

 

Once you get it fixed, repeat the mantra. Battery Tender is my friend.

Edited by Tri750

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tallman

And the starter is a bear to replace...

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BoisePilot

Be careful not to blip the throttle if you start it with the starter engaged! If the starter does not disengage you may drive the starter fast enough to blow it up! The drive ratio is reversed with a started locked in and centrifugal force can blow the armature apart. I saw this happen once on a car and the force was so great it broke the starter housing. What a mess. If I tried the key on method I would turn the ignition off as soon as I heard the engine fire.

Edited by BoisePilot

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dirtrider

Afternoon Jim

 

The BMW uses a modern automotive type over-running-clutch starter drive.

 

The engine really can't back drive the starter motor for more than a nano-second as the one way clutch in the starter drive will just free-wheel once the engine starts & the flywheel speed exceeds the starter motor speed.

 

The one way clutch allows the starter to spin the engine but doesn't allow the engine to back-spin the starter.

 

starterclutchdrive_zps93124589.jpg

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BoisePilot

Good to know.

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azccj
The big K bikes will fry the modern solid state starter relay if you attempt to start the bike with a low battery and are persistent in getting it to start when the voltage is too low.

The exact symptom you describe happens.

 

Once the damage is done, The key can be in your pocket and when you touch the cable to battery, it cranks.

 

The early point type relays could be broken free as mentioned above. Solid state relays just short.

 

There is a retrofit relay kit 61357663945 that will both relocate the relay and prevent this from happening again. (Supposedly)

 

If you continue to let it crank, or of you've done it a lot trying to jar the starter loose, you'll burn the starter up too. The starter is not the problem.

 

Once you get it fixed, repeat the mantra. Battery Tender is my friend.

 

This would be my guess as well, the starter relay has welded its contacts. I don't know if the relay is easy to get to, or if its mounted deep within the bike's plastic. I have a K1200lt but it's a 2005 model so I think they fixed the problem by the time they made mine. But who knows, it was made by BMW after all. :rofl:

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schneeman

Thanks again for ll comments/advice, will start with the relay and see if i can fix it, if not i will have to get the upgraded one which isn't cheap. And sure, on A K1200RS to get to the relay i need to take off the panels and the tank. And I just put it all back together after changing the breather tube...

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kioolt

Back in 92 when this first happened to my 91 K100LT I was able to just lift the rear of the tank enough to remove the relay box cover and tap the relay. A couple of little taps was all it took to unstick it. I've been using the same relay ever since. I never removed it to file the contacts as suggested on some forums.

 

When mine stuck I was over 500 miles from home on vacation, it was on Sunday and it was raining.

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