4000 rpm abnormal vivrations

River west

Standard Bore
Joined
Mar 19, 2026
Messages
1
Ride
2020 Rocket3
Dear all

My 2020 rocket3 is experiencing abnormal vibrations 4000 rpm while riding, regardless of whether it is in nutral,1st,2nd and 3rd gear.
therefore,I decided to have it overhauled this winter.
When dealer mechnic opened the engine, it was found that O-ring on the rea balancer shaft was damaged or deformed.
The dealar reported this abnormality to Triumph.
The following are possible causes of this problem as mechanical engineer.
1.A worker made a mistake when assembling the O-ring onto the shaft and then attaching them to the case,resulting in an incorrect assembly.
2.A different O-ring,although very similar in dimentions(slightly large size), was used.
Personally, I suspect it is a combination of 1 and 2.
I would appreciate your opinions on this situation.

 
Another covid bike. They forgot to put the spacers between my ABS module and the engine. Took them almost a year to figure it out. They were in the process of buying the bike back when it was discovered. I feel like they know lots of the covid bikes were just thrown together with no thought or care. I hope they take care of it for you.
 
Is that gear timed, counter weighted, did this vibration just start or has it been with you awhile? I would think the o-rings would be to control oil flow, either restricting or sealing.
 
May not have had assembly lube.
Assembly fault rubber oring cut during assembly.
Is the support hole still good?