No Cost Performance Improvements
Tires - What can you do to your bike that can help acceleration, gas mileage
and handling? How about checking air pressure in the tires? This
often overlooked, no cost maintenance item significantly influences
tire wear. Set it to the tire manufacture’s specification.
Chain - Another highly neglected item that
we see in our shop all the time is a poorly adjusted and usually
under-lubricated chain. This will significantly affect performance
and handling. A chain with no lubrication eats up horsepower (and
consequently gas mileage). If you don’t believe it, try spinning the rear wheel before
and after lubing the chain. Multiply the effort differential by several
hundred RPM and there is a VERY measurable horsepower difference.
An extreme example is when a bike has been sitting for a while and
the chain starts to rust. We’ve had examples where the rear
wheel wouldn’t even turn and would actually stall the engine!
Chain tension is likewise an extremely important
adjustment. Too tight, (which is most common), and the gearbox,
swingarm and wheel bearings all become over-stressed, the suspension
doesn’t act
freely, and even shifting can become difficult. In addition, the
internal friction of the interface between chain rollers and sprocket
increases, reducing horsepower that could ultimately be transmitted
to the ground. If the chain is too loose, the chance of it jumping
off goes up. Additionally, a very loose chain whipping around beats
up the chain and sprockets and to a lesser degree, transmission
components.
To properly adjust the chain, make sure that
when the countershaft sprocket, swingarm pivot and rear axle are
in a straight line, the chain is just free to move up and down
a very tiny bit. You’ll
find the chain is probably a lot looser when the bike is parked than
you’d imagine.
Steering Head Bearings – A
last thing to check is properly adjusted steering head bearings.
If these are too tight, steering precision is reduced and the bike
may have a tendency to weave at some speeds, as if it had an overly
tightened steering damper attached. Bearings wear much more quickly
in this state. If
the steering bearings are too loose, the forks will transmit far
more shock to the handlebars and frame, the bearings get “pitted” causing “notchiness” in
the steering, and steering precision goes way down…
To
properly adjust these bearings, first make sure the bearings are
in good shape, i.e., not rusty, no pits or score marks, and are
properly greased. Then, tighten them just enough to make sure the
forks swing side to side easily with no drag, but also with no discernable
looseness when the forks are rocked fore and aft. There should be
only the slightest pre-load on these bearings so as to avoid any
of the afore-mentioned wear issues. This slight bit of pre-load allows
for new bearings to seat properly. It should be noted that
these type of bearing adjustments border on art rather than pure
science and as such, adjusting bearings correctly is the result of
practice, practice, practice.
Proper maintenance of your tires, chain and
steering head bearings can reward you with a precision feel in
ride and handling, and add to the longevity of the motorcycle’s
life.
Stay tuned for the next installment where we explore the idea of the
motorcycle working for you, not the other way around. |