Do you own a Kawasaki ZX-10r or ZX-6r with a stock Ohlins steering damper? Have you noticed that no matter where you move the adjuster the damper never seems to be stiff enough? Yeah, we noticed that too! Would you believe there is an easy fix for that? When you talk to most techs they will tell you the best thing you can do to fix the damper is to swap out the “Kawasaki” needle and seat to the normal Ohlins needle and seat. What does that accomplish? Well let’s take a closer look.
First, a lesson in orifice style damping (don’t worry, there is relevance to this). Have you ever taken a bucket of water and poured it down the kitchen sink? If you pour it slowly, the water will just flow down the drain. If you pour the water faster, the sink starts to back up because you are adding water faster than the drain is taking away; the drain hole can only let so much water through at once. To keep the water from overflowing the sink we have two options; either pour the water in more slowly or make the hole of the drain bigger. In this example, our only option is to slowly pour in the water.
Let’s address the “make the hole bigger” concept. If you look at the diagram you’ll see there are 4 orifices of different sizes. So, think of these as different sized
drains in the sink. As you can imagine the little hole will only let in so much water pass through (velocity) vs the largest hole. As hard as you might try you cannot pour it down any faster. The larger hole will allow much more water to pass through right from the start, but at some point will also allow so much flow-through. This is how a damper works! You are pushing oil through a hole. When you push your handlebars slowly back and forth, the oil flows through the hole with very little velocity (remember pouring the water down the sink slowly?). But when you get a tank slapper the handlebars are trying to shove a large amount of oil through the hole and only so much can flow at one time (like dumping the whole bucket in the sink). And that’s why the damper stiffens up and keeps the tank slapper from getting out of control.
I know, I know, but what about the adjuster? How does that come into play? Well, all the adjust does is make the hole bigger or smaller to allow the flow of oil to go through. And how do we do that? With a needle and seat!
When you move the adjuster to make damping stiffer you are moving the needle further into the seat and effectively making the hole smaller. And when you move the adjust to make damping softer you are moving the needle out of the seat and making the hole bigger.
So how does ALLLLL of that tie into what we do at Velocity Calibrations to make your OEM damper work better?!?! We change out the needle and the seat with a standard one from Ohlins. Below is the comparison of the two.
You may also notice that on the OEM needle there is a hole on the side of the needle and on the very tip. Those holes are what causes all the problems with the OEM damper. When the needle is sitting all the way in the seat oil can still flow through those holes! And because, of this we can not get a damper that is stiff. So, we change out the needle with a standard one which completely eliminates those holes and we get stiffer damping. Once this is complete, the OEM damper will have the same performance of an aftermarket Ohlins steering damper.