Jasper wroteI had 20mm spacers on my suspension hoop to quicken the steering on my SP5. I then got some corse yokes and took them off. The bike was incredibly "tippy", literally fell on its side in a corner,roundabouts were a nightmare and unnerving. I messed with the eccentric, to no avail. I moved the wheel back in the swing arm,again to avail.
In a last resort, contrary to everything I thought, I put the spacers back in,which jacked the back up by 20mm. I thought the bike would be so unstable as to be unrideable.
The change was a revelation. The bike turned sweet,was stable and the tippy feeling was gone.
Yet I presumed by raising the rear,it would have made it worse! Go figure.
Jasper-
When you took off the 20 mm spacers and added 27 mm yokes your bike fell into turns so bad that it was unridable.
So now you have stock 30 mm yokes along with the 20 mm hoop spacers and all is sweet.
This is how theory and how a rider feels when he rides his bike start to separate. I often think that theory is a good starting point if your bike is doing something stupid and you want a place to start in getting it straightened out-- but some rider's seem to experience results that are 180 degrees of what the theory says.
By adding the 20 mm spacers you raised the rear ride height and thus reducing the front trail/rake a bit and raising the CG. With the stock 30 mm offset and the raised rear you would have less trail and thus in theory you should have quicker turn-in and a more nervous bike then using 27 mm yokes and no spacers-- but you do not.
My experience on my 888's a bit different then yours. I set the rear hoop to achieve about a 10 degree swing arm angle to prevent too much squat which made my bikes run wide out of a turn. (newer bikes seem to shoot for 12º-14º). I used my threaded portion of the hoop mono balls to achieve this so I did not need spacers. I have to check but I think I have them extended about 12-15 mm. But by raising the rear along with my 27 mm yoke my bikes still do not fall into turns nor make them nervous. Only when I was using G cams did I ever feel one my bikes were pretty nervous.
Once I found the 10º SA angle to work I experimented with other adjustable elements of the bike to make it feel the way I wanted to on the track. For turn in I position my front forks in the yokes until I only have to use minimal muscle to get it to turn in (for me that has never been a light touch). I played with my front and rear sag numbers until when I am in a curve I do not have to do anything to hold a line. I would only change damping clicks for different tracks--
So all of my 888's on the track take some muscle to turn in, have the rear raised so the swing arm is at 10º to prevent running wide out of a turn, and have sag numbers that make my bikes not require any input to hold a line through a turn. I have never felt my track bikes flop or fall into a turn-slow or fast no matter what combination of trail or rear ride height I have used. Could be the slicks I use or my riding style . Marvin says his bike used to fall in at low speeds with the stock yokes. When I rode my SP2 (completely stock or after I made it fully Corse) on the street it seemed pretty stable into turns and in the straights.
This is probably why I remember in the 90's that there were a large variety of "sweet" geometry numbers that each Ducati ride swore by.
We all ride different and set up our bikes differently. I have ridden other owner's 888 and wondered how they kept it on the track- but they loved their set up and would not think of changing it.
