Found my supercharger noise

Time for belts again. This will be my 3rd belt change. I have had a growing supercharger noise. I was thinking the worst, I was thinking engine main bearings. I am relieved to discover it was just belt tensioner bearings. The bearings could twist and wiggle from side to side. When out if the bike and in my hand I could shake them and they sounded like maracas. After searching around and looking at various options via crossreffencing the numbers I thought I would share what I learned. OEM pulley bearings are SKF 6004 2rsh C4HT, 6 indicates bearing design, single row deep groove. 0 indicates the width(this one doesn't make sense to me). 04 indicates diameter series(multiply by 5 gives the bore diameter of 20mm i.d.). 2rs indicated it has 2 rubber seals, one on either side. C4 indicates the clearances inside. C4 has greater clearances than a C3(C0 indicates the standard clearance. Any number larger than that indicates a greater clearance than standard. Some smaller engines request the C4 due to the heat and expansion). What this all means is you are looking for a high quality bearing of your choosing that is a deep groove ball type, 12mm wide, 42mm O.D., 20mm I.D. has rubber seals on both sides and is rated at C3 or C4. I went with Timken. One thing I learned about during all this is that counterfeit bearings are a HUGE thing. I had no idea. There are apps that allow you to scan of a bearing you purchased and it will tell you if it's ledgit. A quick, easy n dirty way to know is to weigh the bearing then look up the specs on the manufacturer website.

After 2 sets of official Ducati belts and many hours looking at videos and conversations I have switched to Cycleworks Exactfit belts.

N4teTheGreat said:

Good info! How loud was the noise? If I ride without my earplugs I can notice a subtle whine from the bike. Belts where done maybe 4k ago. Could just be normal as I tend to worry about every little thing for nothing :-D

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It was noticable by people on the streets. The guys at work asked if I added a supercharger. It had a decent wine to it. I could always hear it and it got louder as the rpm went up. It's not quiet enough I could just tune out. Could even hear it when the music switched songs.

WhiteHyper said:

So how many miles have you done on the bike? 55k miles for third set of belts? What do you think was the cause, belts over tight? I'm at 60000km, belts are due, might look at replacing the bearings.

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I have 25000miles on it. When I set the belts I checked, double checked and checked again so I don't think it was tension issues. I do ride in the winter in mid michigan but the belts are covered and the bearings are sealed so that shouldn't matter. I'm guessing it's one of those things that, they either last forever or they dont. Kind of like how main bearings were a while back. Some guys were needing rebuilds while within waranty on some of the bikes. The guy I bought the hyper from also had a multi 1260 that he just got back from Ducati detroit after having it rebuilt under waranty for main bearings. It's funny because some guys in some groups say to change them every belt change while the guys here are never changing them . It's funny how things are from group to group. Im glad I did it, the alternative would have been engine rebuild.