Hippity-Hop
So I went to some other forums to answer this, then I realized, its not here, so lets put it here!
Here is my question: What is the best way to avoid rear wheel chatter while entering hot into a turn under heavy braking and/or downshifting? And can any of the more experienced members tell us what to do when this happens?
I have a video right now, but its like 2.5gb and I dont know how to compress it. hopefully by the end of the day I can post a gopro vid of exactly what I am talking about.
Under heavy braking, two major elements cause the chatter.
First, the weight normally on the rear wheel is transferred to the front. Second. the throttle-off engine acts as a compression brake. The rear tire unloads and slows relative to ground speed. As it makes contact with the ground, it tries to speed up the engine back to ground speed. This causes a temporary skid as the engine catches up. If the engine is in a high gear relative to road speed, it is not turning fast enough to maintain combustion (below idle speed) and it begins to misfire.
This condition can be exacerbated by a loose chain and/or a cheap shock absorber which causes a hop from road undulations. Since there is also a rotational element from the fully compressed front spring hitting the bump first, the frequency of the chatter will decrease with speed.
The problem is made worse during the downshift (especially multiple gears) as the clutch is released and the engine speed in the lower gear does not match road/wheel speed. The first suggestion is do not use the engine as a brake during the downshift. Match the rev's to meet road speed and gradually reduce throttle.
There are a couple of common replacements which help the problem.
First replace your rear shock with a better one. I make an adapter for the R1 shock (currently out until mid April) which helps for less than $200. Penske, Ohlin and others make aftermarket shocks. Expect to pay a significant percentage of the value of the bike to go that route.
Second, most 'R' series motorcycles have a slipper clutch which reduces engine braking in gear transitions. That also is going to be a fairly expensive proposition on the FZ8.
Third, take an advanced rider/racer training course. If nothing else, you will get some up close advice on riding technique from those who have BTDT.