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PLEASE HELP..... Harmonics Driving me Crazy!

3K views 8 replies 3 participants last post by  Altra001 
#1 ·
Hello Guys

Can anyone assist me in locating Rubber Grommets to subside the Harmonics of my Ducati Monster 796 2012. (Round rubber discs that wedge between the cooling fins on your cylinder heads).

I have tried ebay, etc.... but to no avail.

Any help would be greatly appreciated :)

Cheers
Steve
 
#2 ·
What does it sound like now? I don't remember hearing anything weird on my old 796. Is it something you only notice on your bike or have you heard it on other 796s too?
 
#3 ·
Steve,
I have issues with my '12 796 also. After changing to a 14T front sprocket my harmonic rattle moved from about 5400rpm to around 5100rpm. I also found it is amplified by the springs of my Termi slip-ons.

Is your issue similar? Is it constant or more pronounced at certain rpm's?

I had read about the grommets and would be interested to try this as well.

Cheers


Sent from Motorcycle.com Free App
 
#4 ·
Hello Guys

The sound has been there since new and after months of investigation it was concluded that the issue was Harmonics. (Buzzing/Vibration noise occurs at about 5000RPM)

I had taken my bike to an other service agent and they placed rubber grommets between the Cylinder Cooling Fins. The sound was almost gone as a result. That was 12 months ago the the rubbers have since began to loose their effect (age). I ended up moving them around but now they are not really doing their job.

I need to locate a place to purchase more. I don't understand why they are now so difficult to find. Yes ok it is more of an old school motorcycle issue, but in the odd occasion the issue is still present in modern bikes. I may just have to contact Ducati Australia myself.

I to like you replaced my front sprocket with a 14t. Bike handles a whole lot better and love the ride/feel of the bike. The Harmonics however, drive me crazy! I dont really want to resort to wearing ear plugs.

I might test my bike without the CAT's (Catalytic Converters) as I have Ackrapovic Slipon Exhausts. But Im confident the issue remains the Harmonics.
 
#7 ·
Ok..... Status Update

Locating or purchasing Rubber Grommets is almost non existent these days. Some dealers don't know what I'm talking about while others simply can not find them or event identify a part number. So this calls for a little DYI.

I took a trip the Bunnings and found these rubber square pads (12cm x 12cm x 1cm) used to provide support/stability to things like washing machines and the like to stop vibrations. Looked and sounded like a winner to me but my question was, would they withstand the heat?

I cut them up with a razer sharp knife into small 1cm x 1cm x 5mm squares. After a nice ride to heat up the engine I then touched one on the fin to observe its reaction.... nothing. I then proceeded to insert one and ride around for a week to see how it responded to prolonged temps..... nothing. I was very happy.

I now have my bike loaded with these custom rubber grommets and I can tell you that the Harmonics at 5000RPM is effectively non existent. I am one very happy man :)

I have attached several pictures for reference.
 

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#8 ·
Thanks for the update and I will do something similarly the next days and post an update.

I must say my harmonics are much better than they were which I think is due to both my engine being more run in now at 7,500km and also my new (few weeks) Shoei GT-Air helmet which is quieter, though the harmonics is not such a volume noise.
 
#9 ·
I look forward to your results. I have only reached 6500Km so maybe mine will also quite down. Not that I can hear it anymore.

One thing I just had done the other day was a Dyno Tune and fak me! The difference is amazing! While I only gained 5HP, the bike is so much more responsive now down low. The surges are now gone which makes for a much enjoyable ride. This with my harmonic issue solved I'm one happy man :)
 
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