May 2002
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by Doug Lofgren |
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In
spite of the time I spend with motorcycles, I still enjoy
the same things about motorcycles that my customers do, the
variety of mechanisms that make up the whole and their
relationships with each other. Spending a rainy
spring Saturday cleaning and adjusting your bike can be a
very satisfying experience. And there are plenty of
maintenance items to which a motorcycle will respond. Chain
adjustment, properly done, can improve shifting, eliminate
clanking noises, and take the lurch out of the drive train.
Clutch adjustment can improve shifting and smooth take-offs.
Brake lever adjustments, shift lever positioning, brake
bleeding, etc. All these things
pay dividends in ride quality. Together they can change the
feel of a bike from clunky to crisp. With so many
fascinating, rewarding details to learn about, why is it
that so many motorcycle enthusiasts decide to go right to
the fuel system? The question is
rhetorical. But, it may be some cultural thing, a right of
passage that comes with a certain level of experience,
seniority. Maybe naiveté? Whatever the cause, I have
an idea of how this kind of process starts. It goes back to
another 'basic' of the sport. Everyone who rides a
motorcycle wants 'more'. Don't be too quick to claim that
you are only one impervious to the lure of the motorcycle,
the only one who rides for purely practical
reasons. Although it's
usually more power, it can be more sound, more mileage or
more individuality. The most common addition is an other
than stock muffler. This gives more noise, more
individuality, and more power. Usually, in that order.
Typically, 'jetting' problems start with the installation of
a 'pipe'. Either a 'glass-pack' muffler (loose term) or a
'full system'. To those of us who
see a small portion of the results of this process, the cost
of such a modification isn't simply the cost of the
'slip-on'. It should include the re-calibration required to
extract the performance and more important recover lost
drivability. It's no different than buying your first
motorcycle while forgetting that you need a helmet, jacket,
boots, gloves and rain suit. It happens all the time because
people are 'optimistic'. Why do I think
"Do-It-Yourself" fuel system calibration by the
owner/operator has a low probability of success? Hint; it's
experience. Some time in my early years in the motorcycle
industry I began to understand that the concept of 'tuning'
existed, I wanted to learn how to do it, and I had an idea
of how far I was from doing it. Along with that
understanding, came the realization that the only way to
catch-up with those with considerably more experience was to
utilize the best equipment available. Within a few
years, WIW (long departed Kawasaki shop. Ed) had moved to
15th and Lake Street and acquired a dynamometer. With that
equipment, it seemed like we had been working in a dark
warehouse and the lights were just turned on. That was
twenty-one years ago, 1981 In the later '80s
I worked in the Engineering Department at Onan Corporation.
If I had any doubts about the efficacy of good test
equipment, working in 'big-bucks' dyno cells put the
'frosting on the cake'. I have been convinced from that
point on that there is no substitute for good test
equipment. Each phase in the
discovery process turns on more lights. In retrospect, the
first 'light' was just a candle in the pitch dark. I've
managed to distill the whole painful experience of 'jetting'
into a process, that takes a finite amount of time, that
amount being closer to a day than it is to a season or a
lifetime. So, I don't take
the process lightly. I certainly don't expect that many of
the most senior motorcyclists I know have the equipment or
education/training to do this. And, I do not look down on
someone who can't jet their own carbs, rather I respect a
person who 'knows her/his limitations'. This article is
not about my abilities but rather an endorsement for 'the
process' and the results. There are several excellent
'tuners' in the Minneapolis area. Motorcycles are not a
means of saving money. They don't have to be expensive but
the culture compels us to try to personalize and customize
them. If you can't afford to have the fuel system calibrated
properly, leave it alone. Save the money you spent on the
pipe. Your bike has a better chance of being different if
you leave it alone, anyway. There was a
genuine do-it-yourself guy in the shop the other day asking
about the price of jetting service. They are easily
recognized by the bikes they ride, this one being a Norton.
After his initial response, he demonstrated remarkable
insight by saying, "But then it would be done." The next time
you're faced with a rainy Saturday you could always change
your fork oil. Ever done that? M.M.M.
* This article originally
appeared in the May
2002 issue of Minnesota
Motorcycle Monthly.