Fasteners That Hold: Flange Bolts are In; Flat Washers are Out

The other day I found a used, 6×1.0x12mm Torx bolt with its flat washer still attached, lying
in my driveway. I picked it up and immediately went to my KLR650 to check the two ignition
switch fasteners. Bingo, one was missing and one was coming loose. I’ve despised those
two fasteners since the first day I saw them a few years ago. Flat washers add one more
sliding surface for vibration to work on, and once the Torx head is twisted off during
installation, the recessed round bolt head becomes difficult to access. Since the other bolt
holding my switch is coming loose, I’ll remove it and install two flange bolts with a little low
strength loctite.

If you have a 2008 KLR650, you have the toughest balancer lever available. This beefed-
up, Kawasaki-backed part fortunately also fits pre-2008 models back to 1987. Not only did
Kawasaki avoid the crack-prone, sharp-edged radius found on aftermarket levers, but
they also made the slotted blade thicker than the original and aftermarket levers. What is
the tie-in with the opening paragraph about flange bolts and flat washers? Not only did
this increased thickness strengthen the slotted blade, but it eliminated the need for the flat
washer from the adjustment bolt. This means there is one less sliding surface for vibration
to work on, reducing the likelihood of a loose fastener. A loose adjustment bolt, like a
broken spring or lever, could lead to catastrophic engine failure. If you are upgrading your
pre-2008 KLR650 with the new factory lever, don’t reinstall the flat washer (part #92200-
1263).

In most cases, a high-quality flange fastener, properly torqued, is the best way to hold
your parts together.

Gearing Changes

The best way to get power from a big single is to change the final gear ratio. Why?
Because over-tuned and over-stressed big singles don’t live long, happy, economical
lives. A good example is the mountain ride that Rod Morris and I took the other day on our
DR650’s. I was geared 15/44 (stock is 15/42) which turned out to be a good, all-around
choice for mountain roads ranging from 500 to 6,000 feet. The pace was moderate on the
straights and lazy curves, but cornering speeds in the twisty sections were quite brisk. In
other words, we weren’t trying for high-mileage numbers but pretty much road our normal
pace. At the end of the 130 mile ride, I filled up and checked mileage – 53.6 mpg after
correcting for odometer error. An over-geared, over-tuned DR650 couldn’t touch those
numbers.

The highest mileage DR650’s in our Top Gun group are my cartridge-forked ’02 MSM at
34,000 miles, and “Kenny M’s” 05 street DR at 30,000. Both bikes run perfectly, get
consistent MPG in the 50’s, and use almost no oil. Tuning is dead-stock except for Twin-
Air primary air filters and Top Gun secondary air filters (the pilot screw on the 02 MSM is
opened slightly).

The keys to getting along with less than 40 rear-wheel horsepower are:

A.  Don’t over-burden your bike with weight
B.  Don’t create unnecessary wind drag (anything that increases frontal area, but
especially items like taller windshields, panniers, etc.)*
C.  Always pick the best final gearing for the job at hand (I use everything from
15/43 to 15/47 on my KLR650).

*Todd’s note – tall windshields might not seem like they add drag since they don’t stick up
higher than your torso. However, while a rider without a tall windshield can always
REDUCE frontal area by tucking down; a tall windshield always remains in the wind stream.

Your engine should never be lugged or over-stressed. The result will be longer engine life
and the best gas mileage and drivability possible for the conditions.

My 52 years of riding and racing four-stroke singles has convinced me of the importance
of reliability over horsepower. The most screwed-up, unreliable, breakdown prone bikes
I’ve ever been around have been the ones with highly-tuned and modified engines. All the
horsepower in the world doesn’t mean a thing if you can’t reach your destination.