Boxerworks.com

So I have watched TONS of videos of engine noise and most are louder than mine, but I am still a little paranoid. Does the right cylinder sound "normal" to you? Left is much quieter. Both are in spec as far as valves and rockers, just rechecked yesterday. Bike runs very well, I just want to air on the safe side!!

By the way it is a 76 R75/5 with 45k miles on the clock:)

https://youtube.com/shorts/pdmJLf0FnSU?feature=share

and an up close video....can really hear it here.

https://youtube.com/shorts/tPjtvubQUGc?feature=share

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Have you checked the up/down movement of the rocker arm? There should be no excess play, really only see some oil film movement.

Kurt

Kurt in S.A. wrote: ↑Thu Sep 15, 2022 8:42 pm Have you checked the up/down movement of the rocker arm? There should be no excess play, really only see some oil film movement.

Kurt

Yeah the rocker arms are as they should be, I can barely move them at all, nice and tight.

Part of the right side noise is the oil breather. It sort of sounds like a turkey gobble and is somewhat normal. The other noise sure sounds like rocker arm play. What is the measured gap between the rocker blocks when both valves are at TDC on the compression stroke?

FIXED!! OK so popped off the cover to see if we could pinpoint the noise while she idled, and still wasn't totally apparent, we decided it was the rocker arm. Pushrods and tubes are great and centered, tappets are in spec. After the 3rd attempt at these rocker arms, she is now operating as she should!! It is amazing how such a TINY adjustment can make such a huge difference!!

Thanks everyone for the repsonses!!

Agreed. I haven't checked the valves/rockers on my R90s in a couple years and the engine is normally pretty quiet. I pulled the covers and saw I had about .007-.010" rocker movement so closed down all four to about .003". Re-torqued the heads and set the clearances to .004" intake, .008" exhaust and the motor is even quieter.