TECH
I just needed anoil change
By Wes Fleming #87301 A multi-part saga
Part Two: Replacing the alternator belt
FRUSTRATED THAT MY BREAK- down wasn’t as easy to solve as I expected it to be (see Part One, March 2016) but eager to complete my maintenance tasks, I decided to start at the front of the bike and work to the back. I replaced the headlight bulbs about a thousand miles ago, so they should be good for another 8,000 to 10,000 miles. The next main- tenance item back from the headlight bulbs is the alternator belt. (Ribbed V-belt – 4PK592, p/n 12 31 7 681 841, retail cost $32.56) The alternator belt is critical to the
function of all the electronics on the motorcycle. The alternator (BMW calls it the generator) sits on top of the front of the engine, protected by a plastic cover. The belt goes around two pulleys; the lower pulley that moves the belt is spun by the engine’s crankshaft, and the top pulley spins the alternator. Once the bike is run- ning, the alternator keeps the flow of electricity stable and provides power to the stock lights, sensors, comput- ers and fuel injectors—anything elec- trical that’s on the bike when you buy it new. Your auxiliary lights, heated jacket, GPS and anything else that you added are generally powered by the battery, which this alternator keeps charged up. With a 600-watt output, the alternator has all the capacity it needs, provided the rider doesn’t go farkle-crazy. The first surprise came when I
removed that plastic cover. The lower portion of the front of the engine had corrosion and flaking paint every- where! After doing a bit of research, I
54 BMW OWNERS NEWS April 2016
learned that the early hexheads came stock with a foam insert between the plastic cover and the front of the engine that helped keep engine noise down. The problem is that the plastic cover isn’t on there super tight, and there’s no gasket—so it’s not watertight. Water gets in there, saturates the foam and then eats away at the paint and metal on the front of the engine over time. A little atten- tion with a light solvent and a stiff brush cleared up the worst of it, but the only way to make it pretty again is to replace the gear box cover. The $335 cost and the hassle involved in doing that meant
that mine
would just be ugly. Because my 2005 R 1200 GS is an early
production model (built in May 2004, according to VIN lists), I obeyed BMW’s suggestion to verify that the number of the part I’m putting on the bike matches the number of the one coming off of it—4 PK means four ribs on the belt, 592 means the belt is 592 millimeters around. This same
belt fits other bikes, such as the R 1200 S and ST, R 1100 S, HP2 Enduro and Megamoto, and R 1150 GS, GS Adventure, R, RS and RT models, so most dealers should stock the part. The internet is a handy way to get infor-
mation, and I especially like YouTube when it comes to figuring out how to do some- thing I’ve never done before. I came pre- pared with knowledge gathered from YouTube and friends, so I was ready to use a screwdriver and a piece of cardboard to get my alternator belt on. “Yeah, you could do that,” said George
Mangicaro, the boss at Beemers Uber Alles, where I work part-time. “Or you could use the factory tool. It’ll be a whole lot easier.” He was right, of course. I still used a
screwdriver to remove the old alternator belt. The technique is simple, but the execu- tion requires a little coordination. The fac- tory tool goes on a 1/2” drive ratchet; it’s a rounded, angled hunk of metal welded onto
Beneath the plastic cover on the front of the engine was a foam pad designed to cut down on noise. What it also does is hold water and corrode the front of the engine.
The factory tool for changing alternator belts is an extravagance for the shade-tree mechanic, but a necessity for a formal shop.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132