|Posted on Wednesday, July 11, 2007 - 12:12 pm: ||
Over on advrider, someone noticed that the alternator output is down from 38 amps on the previous bikes to 30 amps on the 08's. This is kind of puzzling, since they've also made grip heaters standard equipment. I checked the specs at buell.com and noticed that they've also changed to a single-phase alternator; the previous Ulys used a 3-phase alternator that was introduced on the 06 Buells.
My guess is that they changed the alternator to the XBRR setup.
The 08's have the oil pump developed for the XBRR, which necessitates moving the ignition sensor to the left end of the crank inside the primary case. The XBRR's had a very small alternator mounted to the inside of the primary case cover, outside the engine's primary chain sprocket. The ignition trigger wheel is on the engine primary sprocket. Previous Buells and Sportsters had the alternator mounted between the engine primary sprocket and the engine case. IF they changed to the XBRR arrangement, it might have necessitated a slightly smaller stator which could reduce the alternator output.
I don't know if this arrangement is required by the crank trigger configuration or maybe there are other advantages? It certainly would be easier to replace a stator mounted to the inside of the primary cover.
Who knows? Maybe the improved cooling on the engine with the bigger oil pump and oil cooler reduce the fan operation enough that the smaller alternator will support the same accessory loads as the larger unit on the earlier bikes.
|Posted on Thursday, July 19, 2007 - 08:53 pm: ||
Perhaps I've missed it, but I haven't seen an answer to this one yet.
All I can add here is that while the rated amps decreased from 38 to 30 (a 21% reduction), the rated power only decreased from 494W to 405W (an 18% reduction). Also, the 2008 specs state that the peak output is reached at 3000 rpm. I don't know how this compares to the older design alternator, but maybe the power output of the new alternator matches that of the old alternator at lower rpms?
|Posted on Thursday, July 19, 2007 - 09:16 pm: ||
Al Lighton commented on it briefly in a thread on the 1125R in the "News" forum. He quoted the output as 32 amps but the specs I saw said 30. He didn't have any specific info on the alternator but he mentioned some other details of the engine improvements that I hadn't seen elsewhere.
You may be right that the rpm the output is rated at changed. Hey, maybe the improved oil pump and enlarged oil cooler will make the cooling fan run so much less that the average surplus power available for running farkles will be the same or more.
Oh yea, I finally did find a photo or two of the 2008 primary cover and it doesn't have the bulge like the XBRR so I don't think it has the outside mounted stator like the race bike. Of course, the change to the left-end crankshaft mounted ignition trigger could still have necessitated a change to the alternator.
|Posted on Friday, July 20, 2007 - 09:11 am: ||
I took the tour of the factory this year and got to see the engines up close.
The timing sensor comes off of the front of the engine.
There must be timing thingies on the crank itself inside the case. (like a twincam)
I think they messed up when they posted the specs.
I bet the alternator is the same.