Front fork oscillation under braking

[GoldOxide_imp]

Clean? What's that?

Slightly shinier than this?

Slightly shinier than this?


or this?

Lol - You must go through a "hose down" before entering the house?

[Cormanus]

[url=https://postimg.cc/mtKVMw1y]

[GoldOxide_imp]

Knarly Cormanus.

Is there gonna be a thread started called, "The most hideous CB1100?"

[the Ferret]

Cormanus would win since I never ride on dirt roads. No sir if I'm riding on dirt it's because I've blown a turn

[GoldOxide_imp]

Heh, it would be interesting to showcase a few in the Estate Realm Dungeons.

[dave]

[quote='ohiorider' pid='235526' dateline='1554410713']
Should probably have said 'fork compresses and rebounds under light to moderate braking."

Sounds like a warped brake rotor. Do you have a dial indicator to check it? I purchased an inexpensive dial indicator at Harbor Freight.

[Cormanus]

Thank you, Dave, for returning the thread to some semblance of sanity.

On the other matter, the Ferret is correct.

[ohiorider_imp]

Dave, I do have an inexpensive dial indicator (Harbor Freight) but it was certainly good enough to check the run out on my R100GS. I doubt it is a run out issue with either of the front discs. More inclined to think that I've gone so soft on the front fork springs, and am running light fork oil. Matt Wiley from Race Tech immediately suggested I move up to either 15 or 20 wt Honda fork oil, since, with the Race Tech Valve, oil wt has little or no effect on compression damping, but is how rebound damping is controlled.

Aside from the very slight pogo'ing issue, the bike's suspension is now compliant enough I can take on most every secondary road in the area. I've only owned two bikes in the recent past that caused me to avoid many of my favorite roads, the 2012 Moto Guzzi Griso, and the CB1100.

Still, I'm going to try the '3M pad and brake cleaner' routine, just to see if the easy fix actually does any good. If not, its dial indicator time!

Bob

[Lord Popgun]

Someone is going to have to explain to me how rotor warpage affects suspension compliance. Cause I don’t get it. Pulsing or shimmy I get.

[ohiorider_imp]

Someone is going to have to explain to me how rotor warpage affects suspension compliance. Cause I don’t get it. Pulsing or shimmy I get.

Popgun, sorry if my original post was confusion. Let me try to clarify. I wasn't intending to imply that rotor warp would affect suspension compliance. I meant that, after making incremental changes to the spring weight and to the Race Tech Valve, that I now have the CB1100 suspension where it is compliant for me and my weight. However, with the .80 weight fork springs, the front end may tend to want to pogo slightly under braking. It's now up to me to determine if this is because:
- rotors have spots where brake pad deposit causes brake to pulsate.
- rotor warpage.
- the fork springs are now so light that minor issues with brakes are transmitted thru suspension.
- If the fork oil is too light, which in turn doesn't control fork rebound movement as it should. That was the opinion of Matt Wiley, an 18 year tech support individual with Race Tech.

Bob