I've been using those Nishioka brace for two years now. Yes, it does work for fore & aft movement, but not on the rotational side.

I've also been using the YS mount from version I through III for about ten years now with good results. However, ever since changing to the non-cdi 185, I started to notice the rubber material on the mount ring deteriorates much quicker, even with the stiffer version III mount which came out right after the 170 period. I've been experimenting with the Taue Mount from Japan - an attachment to the YS mount about a year ago with pretty good results.

Almost 99% of YS pilot in Japan favors the cdi with smoother idle. Therefore, have lesser problem with rotational force. However, some of them also have experienced the rubber deteriorating problem.

Adrian