Bad sounds diagnosed.

[1976RD400C]

The last few times I was out on my RD400 I noticed noises that were not normal as I came to a stop and it was idling. The first time, I'm like the piston is knocking? How, why, they were fresh oem pistons and the bores were fresh. The next time, no, that sounds like the clutch rattling. Why, how, there was nothing wrong with it when I had it apart, it even has those rubber o rings in the plates. I pulled the lever in, and the sound didn't change at all. Well, the last time out I decided I had to pull the clutch cover and inspect. Everything looked fine. Then I noticed the frame rail, The freaking motor is lying on the frame rail and trying to saw through it! The rubber motor mounts are shot. All good now, whisper quiet. There isn't much clearance down there and the 400 motor likes to wiggle around with the rubber mounts. Just a heads up, it sure made sounds that were very concerning. Pics of the frame rail and clutch cover.

[m in sc]

oh shit. glad you found it

[Simmons1]

Good find before something really bad happened.

[RDnuTZ]

are the rubber inserts available anywhere in USA?

[1976RD400C]

are the rubber inserts available anywhere in USA?

https://www.economycycle.com/woocommerce-search/keyword/engine+mounts/search-in/product/cat-in/all/search-other/product,p_sku

[SoCal250]

Good find

[Kawtriplefreak]

Good find!!!