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Lore of the #20 Pilot

Posted: Tue May 23, 2017 9:19 pm
by radare
I started this forum back on November 7th, 2011 as a replacement for an even older Seca II forum called Seca2.forumup.org. You can still see it if you tune in the Wayback machine.

In the days before XJRider, the lore of the #20 pilot echoed through back alleys and basement-level stairwells as the fix-all for a host of fueling issues. From well into the darkness you'd here the whispers: "Gather around my dear friends, I would like to tell you about a cure for what ails you, be it sniffles, scurvy, stomach ailments, eye sight, nervousness, gout, pneumonia, hard starting, lean mixtures, crankiness, tiredness or plum just sick of life... Yes, sir, a bottle of my magic elixir will fix whatever ails you; the #20 pilot jet".

New Seca II owners would stare into that darkness with widened eyes and imagine such a wonderful world, full of power, throttle response, amazing cold starts and 4k smoothness. An how easily this utopia would be attained with the simple replacement of a few jets. . . . .

The notion of the #20 pilot jet upgrade has been around as long as I've owned a Seca II. It's always been the thing you do, right out of the gate. But why? And do we really know that a well-tuned machine runs better with #20's than with #17.5s? Do we know of any ill affects?

Why are you digging up such things, Radare? The Seca II gods have spoken and the #20 pilot jet is their answer. Well, I don't know. But I have a set of carbs in my ultrasonic right now and I'm thinking about going back to #17.5's. Why? Why again, radare?

You see, my good and patient reader, each of my XJ's has exhibited an odd behavior when warm; they get a bog right off idle when the throttle is opened. Every one of them and all with #20 pilot jets.

Now here's the kicker for me: I live at 5,280' in elevation. At this elevation, there is only 83% of the air that is present at sea level. That means, I'll need about 83% of the fuel I'd need if the bike were on the beach. Does it really make sense for me to have these #20 pilot jets?

(Oh, and interesting fact: On that Mt. Evans ride I take, there is only a bit over 50% of the air at its peak than at sea level)