Monday, August 30, 2010

Tuning - Its all in the Details

Since I got the ZRX, I haven't been doing my usual of working on it all the time. I've done a few things like updating the turn signals to something more visible and finishing off the undertail. Here is a shot of the ZRX in the shop with the new turn signals and another of finished rear undertail and turn signals.

We recently had a week of cooler temperatures and I had a chance to put some miles on both bikes. In the process, I started messing around with suspension tuning on the ZRX and came away totally amazed. When I first got the bike, I said that the heavier engine made the bike feel like it wants to fall into corners. In a corner, it takes quite a lot of force pushing away on the inside handlebar to keep it from falling into the corner. I never liked this, but figured it was just part of the package.

Also, the ride was aggressive. So I did a little checking on the Kawasaki factory recommended settings and compared them to set-up as I purchased it.

First of all, the shocks were extremely tight. In particular, somebody had set the forks full tight in jounce and the rear shocks full tight in rebound. I guess they were trying to keep the bike from diving during braking. Happily, I have independent jounce and rebound adjustments on both front and rear, so I was able to easily take it back to recommended settings. Here is a shot of the top of the front fork, that blue aluminum on the left. The screw in the center is the rebound fork adjustment and there is a similar screw at the base of the fork for compression. The silver barrel around that screw is the front spring preload adjuster.

In the rear, I have the 5 steps of spring preload adjustment with height adjustment ring. I also have damper adjustments like the knob in the picture showing the rebound set at level 3 out of 5.

After backing down the shocks from 5 to 2 and a similar adjustment in front, the ride was now plenty soft and I was able to tweak it just a little tighter. Having adjustments with reasonable steps.... Sweet.

But the bike still fell into the corners, so I checked out the heights. The rear was set up high at position 4 out of 5. The front was about 2 mm low. 2 mm didn't seem like much, but I guess that the guy was trying to get the bike nose down so it would have less rake, less trail, and turn faster in a transition. Must have been a young and stupid racer. As for me, I'm old and stupid and like a more relaxed handling and ride.

At first, I decided to make a small change and go from 2 mm low in front to 1 mm high. I didn't really expect to be able to feel this change, but the available height range was pretty small, so I made a small step. What a difference! It still wants to fall in, but its a lot easier to ride.

After talking to Bob about changing his suspension, I decided to take the plunge and lower the rear height. From the looks of it, one step in back was about 3/8 of an inch, but upon measuring is, it was only 1/8" or 3 mm. Taking the bike for a ride and the steering torque is almost neutral, but falling in slightly.

Finally, I'm in the process of taking one step further with another mm higher in front. Now, I just need the hot, sticky weather to back off a little so that I can give it a try.

After more than 30 years of making little changes that improve the character of a car, I shouldn't be surprised how much the little adjustments matter. Still, I am amazed that a few millemeter change in ride height can have so much difference in the comfort and character of a bike. Its all in the details.

Sunday, August 15, 2010

Egg Yolk

If you've read this blog, you have probably figured out that I like to be nice and visible when riding a motorcycle. The very first thing an oncoming driver can see is your helmet, so a helmet that is visible from a distance is important to me.

Many people love fancy graphics and, I'll admit, they look nice when you hold the helmet in your hands, but from 100 yards away, you need a light, bright, solid color to maximize your visibility to other drivers.

Last fall, I was due for a new helmet and, because it was the end of the Snell 2005 era, there were many good deals available. There was also a slim selection of colors as these were the last run of the 2005 spec helmets. In the end, I found 2 helmets, a Shoei X11 (king of good ventilation) and a Vemar VTXE. The Vemar came at such a good price, I thought it would make a good learning helmet for painting. You see, neither helmet was my preferred color and I would need to learn how to paint.

So in this project, I learned about water borne urethane paints, air brushes, and a little about graphics. Oh yeah, and I was totally clueless about mixing paint colors.

The Vemar started out as white with red and black graphics. I forgot to take a "before" picture, so here is a picture of the helmet from one of my favorite websites, WebBikeWorld. This isn't the exact graphics, but its still complicated like what I started with.

My first step was to sand it down and paint it a white base coat. I thought about leaving it white, since the sculpture of the vents looked nice, but I stuck to my plan.

The back of the helmet was getting a checkered flag look with white and yellow. Here is my masking tape checkered flag. I learned that you can mask a pretty clean line with masking tape, but if you pull it off and then need to remask and repaint the line, its hard to keep a clean line because the discontinuity of the paint thickness lets the paint bleed under the mask.

Getting the right paint color was an education. I thought that to make yellow a darker color, you simply added a touch of black. Nope. All that gets you is a muddy green. After being schooled on the color wheel and buying some red to darken my yellow, I came up with two colors I liked. The first was a dark yellow, similar to my old helmet. That was made with 2 drops of red added to yellow. Add one more drop and the color changes to an orangey yellow that I call "Egg Yolk". I decided to paint this helmet "Egg Yolk" because its shape reminds me a little of a fried egg. So here is the end result. Just don't look too close.

I like the way the color turned out. In the car biz, they say that this paint as a lot of "flop". That means that the color looks darker, even a different color, in shadow as compared to direct light. Egg yolk is clearly yellow in direct light, but has a an orange/red tint in the shadow.

I wanted to blend in the "spoiler" on the top, so I painted a black accent graphic. I thought it looked like horns, but my niece says its definitely "Transformers".

In the end, I learned a lot and have a unique helmet that meets my goals. Hopefully next time, I'll make fewer mistakes and not take so long.

Saturday, August 7, 2010

Rocks in my Head

That's more or less what the doctor told me.

One of the interesting things about life is that sometimes, your body lets you know how it works by not working properly, hopefully only for a short while. Recently, I had a demonstration of how amazing the human body is and have been learning about the incredible engineering inside us all ever since.

One morning, I woke up and opened my eyes, only to see the room spinning around in circles. When I lay still looking at the ceiling, the spinning would slowly stop, but I spent the next several days feeling generally dizzy and having to avoid looking up or the room would start spinning again.

Its an incredible feeling of weakness. We take our ability to balance for granted. To have to grab onto walls or a desk to avoid falling down in a crumbling pile when suddenly and unexpectedly, the room starts to spin makes you wonder when its going to stop and will you ever be right again.

In my case, its quite an interuption of my active life. At work, I'm under cars on a hoist looking up (spinning) and checking out the suspension. I also drive cars, including evaluating handling, which could bring on the vertigo, as a primary part of my job. At home, I'm either working on projects in the shop (refer to hoist, above) or riding my motorcycles. The thought of having the world spin around while riding the motorcycle has kept me off them since this first occurred.

So I made an appointment with the doctor and he told me I had rocks in my head. More accurately, we all have stones in our inner ear that form part of a balance sensor in each ear. Think of it as an accelerometer that helps our brain figure out which way is up. In my case, one or more of the stones has become displaced so the left ear is sensing gravity differently than the right ear. My brain is reading these two different signals and trying to make sense of it and not doing a very good job, hence the spinning room.

Now the good news is that it should go away over time. The sensor cells that are missing stones will shut down and my brain will reprogram itself for the signals it has available. That alone is amazing.

Look at the design of this tiny accelerometer. The stones are a mass that responds to gravity or other accelerations. The stones float in a damped, flexible layer that supports them and flexes side to side when accelerations move the stones. The hairs flex with the stones and send signals to the nerve cells letting the brain know which way the head is being pulled. Your brain then processes these signals and lets each of us sit, stand, run, jump, or do cartwheels. It also lets us drive or ride a motorcycle by letting us know, in combination with our eyes, which way is up and how fast we are going around a curve.

This system not only lets us know which way is up, but if we are accelerating or braking or, by the difference between left and right ear, turning our head to look left or right. That very key factor lets us know if the tail of our bike or car is sliding out on a corner. It tells us if, in NASCAR terms, the car is pushing or loose.

It has always been clear that some people have more sensitivity to the handling of a car than others. I've always been grateful that I been more sensitive than most as its allowed me to have my career and a lot of enjoyment over the years. Now, I have a subjective understanding of the engineering inside my head and appreciate it all the more. Yes, my body is getting older and breaking down. My days of being the best driver on the track are gone, if they ever were. But the world and our bodies are both an amazing place to live in.

Monday, August 2, 2010


Early this spring, it was cold, wet, and windy. It was a personal challenge to get any riding in on the motorcycles. Then, suddenly in late May, Michigan turned to hot and humid with plenty of rain and serious thunderstorms. All that got me interested in the idea of having a thermometer on the bike. At least that way, I could tell with authority why I was uncomfortable.

I settled on a Marlin's, partly because its the biggest and easiest to read and partly because he is a Michigan business. That way, I get to pay sales tax.

There are lots of ways of mounting gauges like this to a bike. I chose a mounting that hid my fork stem and was partly shaded by the handlebar. I enjoyed making the curvy shaped mount. Its really too fancy for the KLR, but it looks good anyway.