BMW GS starter motor / bump starting

**Nigelrojo** · #1 3 Oct 2006

I had a BMW R100GS from 1990-2000, did 50,000 miles on it and the only thing that ever broke was the Valeo starter motor. This happened during a tour of the Alps. Fortunately I was able to bump start the bike and ride it to an Italian garage, where they replaced the Valeo item with a heavier, more robust Bosch motor, which never gave me problems.

2 weeks ago the Valeo starter motor on my '97 R1100GS decided to disintegrate; the magnets dislodged and sort-of mashed themselves up inside the commutator casing. It was an easy enough job to remove the starter motor, and I thought I would then simply bump-start the bike.

Bad idea. 30 minutes later I was a sweating, gasping wreck. Every attempt to bump start the bike, even with 2 blokes pushing, resulted in the back wheel locking up, even in top gear. We even tried towing the bike behind a car, which (predictably) resulted in me falling off. I had to admit defeat and call recovery. The recovery chap cheerfully stated that the only way to bump start a BMW oilhead is to have 2 people on the bike and "a big hill".

Any suggestions on how to bump start these bikes (especially on your own) would therefore be gratefully received. Maybe it simply isn't possible, I don't know. If it isn't possible, then that's not good news for folks intending to take their Beemer to the back of beyond. IMHO all bikes should either have a kickstart or be bump-startable.

Also, does anyone know if a properly engineered Bosch starter motor is available for BMW oilheads? Despite having just fitted a new Valeo (it works fine) I simply don't trust them any more.

Nigel

**Margus** · #2 3 Oct 2006

This is how the french (Valeo) build starters - gluing the magnets inside

I've heard one similar case as well when the magnet's have comed loose. You only need to glue them back and it works as new.

Push-starting the bike, i haven't got a need for it yet, but i think you need to do it in 3rd, 4th or even 5th gear, depending if you have any hills or a loose surface, the worst. Engine braking is massive on oilheads. Ignition on, clutch engaged you need to push a good human running speed, then jump on and on 4th it should get enough to turn the engine. Clutch release is another trick, doing it slowly usually can block the rear wheel on lower gears, takes some practice.
Oldschool experienced motocross riders did it like this - run a good speed with the bike cluch engaged, jump on then quickly stand up (or even jump up if you can) on footpegs and "freefall" your butt into the seat as far rear as you can at the same time rapidly releasing clutch, then the rear wheel gets enough traction from your (over-)weight not to block and turn the engine, useful especially on the loose surface

My home garage has about 2 metre quite steep drop down, sometimes i start there on 4th with only igition on. Or in the very cold days to give enough voltage for ABS to sart without using the starter.

**Gecko** · #3 3 Oct 2006

I reckon that by removing the starter motor you have done something to the electrical circuit so as to make it impossible to start. I've towed and started a couple of oilhead Beemers in my time, most recently a 1200GS and normally 3rd or 4th gear, like Margus says is all you need.

Dontcha love it when the new bikes break down and have to be rescued by the old ones

**Mr. Ron** · #4 4 Oct 2006

If you want to replace the starter, i would recomend one of these. Their lighter, use less amps and are a repairable Japanese design found on most Toyota's. An excellent upgrade in my opinion!
http://www.motoelekt.com/

**Nigelrojo** · #5 13 Oct 2006

Thanks guys, some excellent info there.
Nigel

**PIRATE_CIA** · #6 9 Jun 2011

I am only 75kg's and have bump started my R80RT on flat ground by removing one spark plug. The bike will start in second gear and will run on one plug.
While the bike is still running replace the plug and lead.

No problem. Hope this helps

**dc lindberg** · #7 9 Jun 2011

I have read that some have succeeded in push-starting the old 1000cc, even the 9.5:1 engine modell. My personal experience matches that of yours with your 1100 oilhead = defeated by the bike.

Solution in my case:
- bosch starter motor and jumper-cables.

Do not think there is space enough for an old bosch starter on the oilheads... if there is, the bosch starter would be the way to go.

As for my R80 - sure. No problem in push-starting it. Had to do it several times. Darn tricky when the skiis are mounted (!), but can be done. Even with about 10.3:1 compression-ratio it was fairly ease to push-start. But the 1000cc engine... shear impossibility

...

It's been 5 years since your posting. How did the situation resolve, and what did you do about the starter-motor-question?

**palica** · #8 9 Jun 2011

To get good information on starters, I would go there instead of Motoelekt:

Valeo and Bosch Original Equipment New Starters and Service Parts

If you can't jump start a motorbike, forget the kick start... On airhead, kickstarting the engine is only possible on a perfectly tuned engine. Considering the greater displacement and higher compression on a oilhead, a kick would be useless. I can start my R90S with a kick but I think I'm at the limit of kisckstart possibilities.

The Valeo starter was a great starter: light, very powerful and low demanding on the battery. You have the possibility to replace it by a Bosch or just change the magnet housing for a new model with retaining clips. The glued-magnets were the only problem of the Valeo and it has been fixed now (unfortunately too late for the airhead production). The new magnet housing can be bought from here: Valeo - Starter Magnet House [clockwise]