My Denso Alternator let me down at a mere 29343 miles. Surprise surprise, it was not the usual failure of broken casing, but an electrical failure. No electrical output as recorded on the GS-911WIFI. Interestingly no fault codes logged anywhere, just the usual failure warning from the bike saying no charging, and of course really rough running.
So I took the alternator off the bike to bench test it, and sure enough the field windings have an open circuit. I eventually managed to strip the alternator down, the hardest part was removing the pulley, once done, I had access to the Rotor and the field windings. The fault was obvious. Corrosion had destroyed a very small portion of the copper winding giving a gap of about 2mm, which I had to bridge somehow, so I set about making a small metal sleeve which I could push the two ends of the broken wire into and solder up, making a solid connection.
It worked, and after coating the repair with electrical varnish/lacquer to prevent further corrosion. I was ready to reassemble.
I was always intending to fit the Bosch alternator as fitted to the RT, but there were none available second hand anywhere in the country and those from Europe and USA would have been a risk not worth taking. The Denso alternator gets a bad reputation for cases cracking up, but aside from that the alternator is really well built, and easy to strip and reassembly as it’s modular in construction. Which makes it a pity as there are no spare parts available either for it or the Bosch alternator. Failure and you’re either buying a second hand unit, or off to BMW to give your credit card a caning……
So I took the alternator off the bike to bench test it, and sure enough the field windings have an open circuit. I eventually managed to strip the alternator down, the hardest part was removing the pulley, once done, I had access to the Rotor and the field windings. The fault was obvious. Corrosion had destroyed a very small portion of the copper winding giving a gap of about 2mm, which I had to bridge somehow, so I set about making a small metal sleeve which I could push the two ends of the broken wire into and solder up, making a solid connection.
It worked, and after coating the repair with electrical varnish/lacquer to prevent further corrosion. I was ready to reassemble.
I was always intending to fit the Bosch alternator as fitted to the RT, but there were none available second hand anywhere in the country and those from Europe and USA would have been a risk not worth taking. The Denso alternator gets a bad reputation for cases cracking up, but aside from that the alternator is really well built, and easy to strip and reassembly as it’s modular in construction. Which makes it a pity as there are no spare parts available either for it or the Bosch alternator. Failure and you’re either buying a second hand unit, or off to BMW to give your credit card a caning……
