Alternator Belt/Pulleys

[Softtail]

I have been thinking about replacing my alternator belt on my 2002 R1150RT so I went out and bought a new belt. I looked at my aftermarket shop manual and there is all this stuff about new vs old pulley systems, maintenance free belts etc. With a 2002 RT, do I have the new/updated pulleys or the old fashioned alluminum pulleys? Since it recommends that the old pulleys be updated with the new ones, it would be nice to know what kind I have before I take things apart. Do you need a puller to get tho old pulleys off? <<<<<<Softtail>>>>>>

[bmwmick]

I have been thinking about replacing my alternator belt on my 2002 R1150RT so I went out and bought a new belt. I looked at my aftermarket shop manual and there is all this stuff about new vs old pulley systems, maintenance free belts etc. With a 2002 RT, do I have the new/updated pulleys or the old fashioned alluminum pulleys? Since it recommends that the old pulleys be updated with the new ones, it would be nice to know what kind I have before I take things apart. Do you need a puller to get tho old pulleys off? <<<<<<Softtail>>>>>>

 

You have the new steel pulleys. That happened in late '94. Your belt should be, 12 31 1 341 779 (BMW) or you could try what I use. I'm using a Goodyear Gatorback:

I ordered the 4040245 Gatorback for the RT. It was $6.41

 

Here is a good site for belt nomenclature.....

http://www.goodyearbeltsandhose.com/cars/gatopoly.html

 

I think the new segmented serpentine belts will flex better around our small pulleys and may last longer. Guess we'll see. Bought my belts here ......

http://www.pickproparts.com/PartsList.aspx?PartNumber=4040245

 

I now have about 15K trouble-free miles on this belt.

 

Mick

[KMG_365]

You have the new steel pulleys. That happened in late '94. Your belt should be, 12 31 1 341 779 (BMW) or you could try what I use. I'm using a Goodyear Gatorback:

I ordered the 4040245 Gatorback for the RT. It was $6.41

 

Mick

Mick,

 

There was also an upper pulley change starting with build date July of 2003. The upper pulley has a different number and the belt is also different. I was going through belts rapidly and I thought perhaps I had the wrong belt, so I bought one of the later ones (# 12 31 7 681 841) since my RT was an '03, but then I realized it was built in July of 2002 (making it a 2003 by our crazy US marketing) and so would still use the earlier belt (# 12 31 1 341 779).

 

I hadn't heard that there was a need/benefit to changing out the upper pulley on pre-07/03 built bikes for the later (improved?) version. Even with the recommended one-time re-tensioning at 6K (for 1150's), I still can't get more than 32K miles out of a stock belt. Since I had one go at only 27K, I just change them out now every 24K and don't worry about it . . .

 

 

. . . although I never travel without a spare!

[bmwmick]

Mick,

 

There was also an upper pulley change starting with build date July of 2003. The upper pulley has a different number and the belt is also different

 

 

Yep,

That whole changover to the new Elast belt and the free-wheel style alternator pulley was handled poorly. Most of the dealers didn't want to be up front with the information.

There is a range of adjustment on the alternator to allow the New style belt with the old style pulley but not the new pulley with the old belt. (we're talking the free wheel pulley here).

 

Do you have an excessive load on your alternator?

 

Mick

[KMG_365]

That whole changover to the new Elast belt and the free-wheel style alternator pulley was handled poorly. Most of the dealers didn't want to be up front with the information.

 

There is a range of adjustment on the alternator to allow the New style belt with the old style pulley but not the new pulley with the old belt. (we're talking the free wheel pulley here).

Ah! A free wheel pulley you say, eh? Well that explains why the new pulley replacement is more than three times the cost of the old one!

 

Do you have an excessive load on your alternator?

Hey! Are you calling me a load?

 

Yes, I do have most of the following running all the time: 2 stock fog lights (35w each?), Running lights (all four turn signals from Signal Minder) on Level: high (x4, wattage?), high beam during the day, 2 Amber Motolights (50W each), and of course parking light and tail light, motronic, fuel pump, EVO servo's whining hard in the twisties, grips in the winter (no electrics yet), etc. Most of our riding is during the day as Les is not as comfortable riding at night. The rest of the farkle suite draws milli-amps: 2610 GPS, V-1, XM radio, Autocom, Kenwood GMRS radio (which I guess is 2W, so that's something).

 

The other problem for us is we have that wonderful civilian six-speed tranny and the sweet spot on the highway in top gear (so you don't feel like you're lugging that poor boxer) is about 75-80mph. I'm seriously thinking of getting on the "parts wanted" list at Beemer Boneyard for a gently used (read: crashed) RT-P tranny with the shorter sixth gear to replace my current one with 103K miles on it.

 

Lastly, we also ride across the desert during the brutal SoCal summers at least half a dozen times a year. Out there the air temps about two feet off the ground can reach well over 150*F which, combined with the load and speed, is what probably kills the belts. In the twisty stuff Leslie routinely runs a gear lower than me so she gets more engine braking than I do, plus on trips I'm carrying more gear than she (not to mention I start out heavier as well). Her belts seem to last a bit longer--I replace them anyway at 36K, but I can't recall how bad they looked when I've changed hers out.

[bmwmick]

Hey! Are you calling me a load?

 

 

Lastly, we also ride across the desert during the brutal SoCal summers at least half a dozen times a year. Out there the air temps about two feet off the ground can reach well over 150*F which, combined with the load and speed, is what probably kills the belts. In the twisty stuff Leslie routinely runs a gear lower than me so she gets more engine braking than I do, plus on trips I'm carrying more gear than she (not to mention I start out heavier as well). Her belts seem to last a bit longer--I replace them anyway at 36K, but I can't recall how bad they looked when I've changed hers out.

 

Hey 'Loadie'........errrrr Jamie,

 

Yes you are loading that system pretty heavy but not to the point of failure. I would expect you to go through more belts (you should try the goodyear I mentioned above) and more alternator brushes than the normal rider with few farkles.

 

I can relate to the hear, I make that I-8 trip more than I like. Being in Tucson is a little better since I live about 3,000' but getting across that desert almost isn't worth the fun I have up PCH above SLO. : ))) Last Sept I came through there and it was 115 in Dateland so we stopped for a shake......stayed almost 2 hours. UGGGGGLLLLLYYYYYYY

 

Mick