Join Date: May 2004
Location: Toronto, Canada
Shop-manual suspension settings were out to lunch on the '04 (too harsh). With your changes to the linkage and swingarm, you are going to have to do this from square one.
Have you done your rider-aboard static sag measurements and set-up yet? For a street bike, as a starting point, front sag should be near 35mm, rear around 30mm. Change the preload settings at each end in order to achieve this (or come as close as possible).
Don't go ANY further unless the bike has new (or very close to new) tires with the pressures set to where they should be (not necessarily what the book says). Going any further with adjustments using worn tires will have you chasing your tail.
Now, with the suspension at an appropriate position in its travel (sag) and with good tires, go ride, and find a smooth reasonably-constant-radius corner, preferably a set of them, ideally this should be done on the race track. When cornering at a moderate pace, how does the steering feel mid-corner? I always aim for as neutral as possible. "Neutral" means the bike doesn't want to stand up and fight your input, and it also doesn't want to fall in and wash out. It should feel as if you could take your hands off the bars and would continue at the same lean angle.
If it resists your input and wants to stand up and go straight, the bike needs to be pitched forward to steepen the steering head angle and reduce the trail (most common situation). If it feels unstable like it wants to fall in and wash out the front, it's the other way.
If the bike wants to be pitched forward, you can either lower the front ride height (slide forks up in the triple clamps so that more of the fork projects above the upper clamp) a couple millimeters at a time, or raise rear ride height by inserting washers between the upper clevis of the shock and the frame. Which one you choose depends on whether you want to lower or raise the whole bike ... which affects the swingarm pivot height (and together with that, the swingarm down angle) in addition to affecting the cornering clearance. For the moment, take your pick, but it's easier to do the forks first. Just understand that raising or lowering the whole bike affects the swingarm pivot height and that affects grip coming out of corners. You may have to come back to re-visit this decision later, and that's OK.
Once you have the sag and ride height in the ball park then arrange for a zip-tie tightly secured to one fork leg and to the shock rod to find out how much travel you are using in compression. As you ride harder, it will use more travel. Approaching bottom-out (and the sag is in the correct range)? You need higher spring rates. I fought this with my race bike (not ZX10R) all last year after changing wheels and using different tires.
You will notice that we have not touched on the "clickers" yet even though that's the first thing many riders think of. Suspension travel first, then geometry, then spring rates, then damping. And they affect each other, so having to go back and re-visit something is completely normal and happens all the time. But if the fundamental geometry (ride height, swingarm pivot height, steering angle and trail) is wrong, no amount of playing with the clickers will fix it - that's why you have to get the other stuff right first.
This is only scratching the surface and there are plenty of books to read. Andrew Trevitt's book on sportbike suspension set-up is a good one. So is the Race Tech "suspension bible".
Helibars, MRA screen, Ohlins damper, reversed shift pattern, sorted suspension, braided lines, Michelin Pilot Power, all else stock 'coz it's fast enough!