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This is a quirky series based on no facts or guidlines
besides, "some filtration is better than nothin'." When we rebuilt
the top end of this 61-inch '48 EL, we added two beautifully
finished, hand built/altered Panheads that accept two polished 42 mm
Mikuni carburetors. We didn't know what the hell we were going to do
about air cleaners at that point. The heads were originally modified
thirty years ago, but recently rebuild, ported and flowed by Baisleys
in Oregon.
If you want a set of heads carefully dialed in, Baisley is
the family team to do the job. I was so impressed with their
workmanship I kept the heads at my office to show them off to
visitors.
Originally, when I finally installed the heads we didn't know
what to do regarding air cleaners or even velocity stacks. The
problem was my long leg. If I ran velocity stacks and leaned my leg
against them, I would shut off the air flow and kill the bike. In
addition, since the carbs were on the outside of the engine on the
left, they were obtrusive. That aspected of the problem dictated that
I not run anything that stuck out any farther.
If I didn't run anything at all there were two negative
conclusions. One, since the carbs were stuck into rubber spigots,
they would fall off if not held into position (many Mikunis are held
in place with the air cleaner backing plates which are bolted to the
engine). Second, if my leg brushed the openings of the carbs, I would
shut off the air again. I had to do something. My first nutty notion
was to create a rough dual cage that would prevent my leg from
shutting down the carbs. It worked, held the carbs in place, but
didn't contain any element of filtration.
I'm not a velocity stack sorta guy. I'd need to be a lot
richer to consider sandblasting the inside of any well-running
engine. So my cage system bothered me from time to time. I stumbled
into a Jap Bike shop recently and discovered foam sock air cleaners
for dirt bikes. I bought a couple, modified them, slipped them over
the brass belt buckle cages and fastened them with tie-wraps. Done
deal, but it wasn't perfect and hindered the air flow into the mouth
of the carbs.
That's when we slipped on beer-soaked thinking caps,
pondering our options and alternatives. I also spotted those little
Pep Boys, single-throat, air cleaners with the paper elements. Chris
Kallas pointed out a notion at Larry Settle's bike shop one afternoon
behind a couple of brews mixed with white-lightening. If I developed
a flange that aligned with the mouth of the carbs, much like Velocity
stacks, the air cleaners could be clamped in place. I took his notion
and ran at it like a blind dog digging for a bone. The more I worked,
brazed and ground the more trouble I ran into. The concept was cool,
but it wouldn't hold the carbs aligned, plus I still needed some sort
of cage to keep the foam aircleaners from collapsing against the
mouth of the carbs. I fitted, ground and attempted to braze the
pieces together.
I noticed at the muffler shop that the tubing said aluminum on the
side. I asked one of Tim's helpers if I could braze to it. He said,
"sure." The tubing was steel, just coated with aluminum. You can weld
to it, and you can braze to any areas where the aluminum coating has
been ground away. After four hours of off and on brazing and
destroying two more foam air cleaners I tossed the whole works in the
shit-can.
I took a ride to Pep Boys and inspected their vast wall of
varied sized paper air cleaners. I found something I thought might
work. In fact these units would fit right over the mouth of the
carbs. Ah, but that wouldn't hold the carbs in place. I went to my
buddy's San Pedro Muffler shop and laid the notion on him. We had to
make two, 1-inch segments of exhaust pipe and expand the opening on
one end to fit over the mouth of the carb for alignment and the other
end just slightly to fit snuggly inside the air cleaner. This was a
trick and took several trips to the muffler shop, until Tim, the
owner, threw us out. The small segments created some difficulty while
trying to expand one end without damaging the other.
He finally came close and I took the segments back to the
headquarters and began a series of alterations to make all the
elements fit. I ground the inside of the segment that was going over
the Mikuni mouth. I sanded and ground the aluminum area on the carb
to accept the tin exhaust tubing, which would hold the carbs in place
perfectly. Finally I saw success ahead as each segment finally fit.
Then I cut the strap for the center after I made a diagram and
attempted to fit the two segments together on the bench. Once on the
carb it didn't fit, and I had to start the strap process over. This
time I put the tubes on the Mikunis, then cut and ground a piece of
bar stock to fit. Then all the elements were transfered to the
welding bench. I found a flat surface and began to weld. I attempted
to gas weld first. I was concerned that I would blow through the thin
exhaust tubing with my new MIG welder (I lack experience).
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