Bump Starting a GS

[bobframe]

If I was to find my battery in depleted state and there was a nearby downhill section of roadway....could I safely (from an electrical system standpoint...not my physical safety) bump start the GS? That is, turn on ignition, put the bike in gear (2nd??), pull in clutch, roll down the hill and release the clutch? Did this once with my ST1300 and it worked fine...but I know nothing about BMW at this point.

Thanks so much,

Bob

[henzilla]

Have done this a few times on various R1200's,among other bikes. short answer is yes, but I used third gear. As long as any voltage is present and the display is lit, it will crank.

Double check the kill switch is in RUN position...pushing it back up the hill is not so much fun!

[pffog]

You do need juice enough to run the fuel pump and ignition. So if battery is really depleted get rolling first , then flip on the key just before you let the clutch out, and yes 3rd, 2nd will likely cause the rear wheel to skid, big twins take a lot to turn over, compared to a 4 banger.

[EMSimon]

and yes 3rd, 2nd will likely cause the rear wheel to skid, big twins take a lot to turn over, compared to a 4 banger.

Tell me about it... During our summer trip to Maine, one of us (R1150RT) had a problem with the starter gone south. We had to push start that sucker several times until he was able to get to the nearest dealer. I think it took us 12 tries at one time in a parking lot before it fired.

[Pauls1150]

Would the starter button also have to be held in, to prime the pump?
Some bikes require this...

[pffog]

Tell me about it... During our summer trip to Maine, ......... We had to push start that sucker several times .............

Damn, in Maine there should be ample hills to park on top of, and walk to your destination.

Had to do that with the wife's bike a couple months ago, battery was getting poor, and we took a nice ride to have lunch on a warm fall day. I Jumped it to get it started, and hoped it would charge as we rode. I found a hill on a side road just out of town from our destination, and had her shut it off and try to restart, no luck, battery was on its last legs, so we parked it off the road, and she rode Pillion to lunch and back.

Had enough juice to roll down and bump after lunch, but at a stop sign about 20 miles from home it petered out, and there was not even enough juice left to run the fuel pump to bump it. So she rode pillion back home and I took the trailer out to get it. I should have tossed the battery from the track bike in the trunk, and a length of wire, I could have at least wired it in quickly to run the bike once started.

[henzilla]

Would the starter button also have to be held in, to prime the pump?
Some bikes require this...

Haven't needed it on F650's, R1100/1150/1200's or on a Wedge K...have sadly done all of these somewhere in time. The pump usually comes on with any voltage..well, except for really discharged/left the key on for a few hours situation But I'm not naming names

[na1g]

How super-human would you have to be to bump-start a 600 pound twin-cylinder motorcycle in a flat parking lot? My arms ache just thinking about it.

pete

Remember when motorcycle roadraces were dead-engine starts? Bump-starting a Manx Norton took some strength and technique... and luck. I had a Ducati 250 Diana whose kick starter was useless. Run-and-bump starting was very stylish back then.

[Pauls1150]

Never had the opportunity (yeah, right...) to bump a GS, but I've had enough other bikes to enjoy the thrill.

If you don't have a second person, the hardest part is the synchronous ballet of getting a leg over while you dump the clutch.

[marchyman]

If the battery is truly shot you are not going get the bike started with a simple push. The one time I had to bump start my GS I was glad I was on a longish and steep hill as the engine wouldn't start until the bike was going about 30 MPH. That did result in two notes to self: 1) remember to turn off the ignition after killing the engine by dropping the side stand as otherwise lights (including the extra 100 watts of aux lighting) will soon suck the battery dry; and 2) carry jumper cables.

Without enough juice neither the fuel pump nor the engine management computer will run. If they are not running your bike is not going to start. If your battery is dead enough you can not generated enough power by pushing the bike.

[dbrick]

If the battery is truly shot you are not going get the bike started with a simple push. The one time I had to bump start my GS...did result in two notes to self: 1) remember to turn off the ignition after killing the engine by dropping the side stand as otherwise lights (including the extra 100 watts of aux lighting) will soon suck the battery dry; and 2) carry jumper cables.

I stopped for lunch at Panamint on the way into DV, used the kill switch (because the lot wasn't level) and forgot the ignition switch. Serious battery deadness resulted, but I found a jump and after an hour's ride to Furnace Creek we were back in business. My two take-aways were exactly the same as yours!

[Omega Man]

Interesting info. I had a sudden death of a battery a while back and, to shorten the story, it seemed without- I think it was at least 9.2 volts to run the computer and injectors/pump- nothing. Perhaps someone else has charted the voltage to confirm. BTW, this is one of the draw-backs to always on headlight/lights. When you are trying to bump-start the bike, voltage seems to be at a premium. OM

[rtwiz]

You do need juice enough to run the fuel pump and ignition. So if battery is really depleted get rolling first , then flip on the key just before you let the clutch out, and yes 3rd, 2nd will likely cause the rear wheel to skid, big twins take a lot to turn over, compared to a 4 banger.

pffrog:

I don't think that method will work. The system diagnostics have to run first, then the bike will start. Turning the key on at the last minute is too late on these bikes.

[rtwiz]

Would the starter button also have to be held in, to prime the pump?
Some bikes require this...

Pauls:

No. "prime the pump????" Really????!!!

[PALADINWEST]

I have started my GSA a number of times by bump starting it. You do need enough juice in the battery to run the fuel pump, the BMS-K motor management and the key antenna (EWS). If the battery is real low I have gotten it started by turning the key on just before the actual "bump" (otherwise all I could get was the engine turning and no ignition with the EWS warning on).
My HP2 Sport in another story, I have never managed to get the engine to spin past TDC, it just breaks the tire loose (no matter what gear - including sixth).
I can bump start my K100RS by straddling the bike on the flat and taking three steps forward.