12 RT buzz?

[flobti]

My 12RT has about 4000 miles & today was the first time I did any significant interstate riding. At 70-75 mph, there was significant buzzing vibration, especially on the trottle side. I never noticed it before, probably, since I never held the same RPMs for any length of time. Other than the poor AM reception, it's the first thing I've found I don't like about the bike.

 

Is that normal? Will is get better with wear?

[PaulW42]

At 70/75, you are doing less than 4k rpm so I would not expect it to be vibey at all. Higher up the rev range, there can be a fair bit of vibration (more of a tingle really) until well run in at those higher revs.

 

I suspect your throttle bodies need balancing. At 4k, this would seem to be the most likely explanation.

 

Paul

[flobti]

Actually, as I recall, the RPMs were around 4200.

[ShovelStrokeEd]

It is a large displacement twin with offset cylinders. It is gonna vibrate at some point or other. Run it up to 4600 or so and don't be surprised if it smooths out. That is a very common resonance point. You can easily ride around it by using 5th gear with no damage to the bike at all. And NO, your not screaming the motor doing that, you are merely riding around a period of vibration.

[PaulW42]

Actually, as I recall, the RPMs were around 4200.

 

For mine: At 70mph indicated, RPM 3600; at 70mph actual 3750. 75mph indicated 3850, 75mph actual 4000. Probably down to variation in the accuracy of the RPM indications.

 

Cheers.

 

Paul