Gary,
I am glad to hear that worked out for you. IMHO ... your explanation
is absolutely correct ... when you put your legs up behind the air
cover you were increasing the "ram" effect, (relative pressure at the
carb mouths) ... The air cover traps incoming air like a sail and
creates a substantial "high pressure" area. This is of little concern
with un-obstructed individual filters but with the airbox on, (at
least the base), then the carb intakes are operating at a "higher"
pressure reference at speed. Since fuel is "supposed" to be drawn out
of the fuel bowl into the venturi via the needle jet .. any
significant difference in the reference pressure is going to screw
with the mixture .. In your case you were running negative in the fuel
bowls so it was not wanting to come out and was creating a lean
condition.
This is an interesting concept for sure ... but this is why "real" ram
air setups and turbos always have the carbs encased in boxes or the
fuel bowls connected to the positive intake source ... The opposite
condition can be created by putting on individual filters and leaving
the bowl reference tubes up in the air cover area, (just attach them
to the top fake scoop screws), ... this will help "push" fuel out of
the fuel bowl at speed and make you run richer, (not necessarily a bad
thing ... depending on how you are tuning .. ). I am aware that
dynojet mentions "removing" the hoses on stage 7 setups in their
"trouble shooting" tips ... for this very reason and I assume PCW ..
expects that anyone purchasing one of their "monster" motors would be
running individual filters ....
Just one more thing that makes us "all" crazy when trying to get the
same performance on the road that we got sitting on the dyno.
campbell
----- Original Message -----
From: "Gary Rathbun" <[EMAIL PROTECTED]>
Subject: TC strikes again!
> Carburetor problem solved!
>
> Some of you listers may remember me posting a few
> months ago about a problem my TourMaster was having
> when I put my feet on the cruise pegs at highway speed--
> sputtering, acting like it was really lean.
> snip <
> The tubes make the pressure in the float bowls more equal
> to the pressure of the air in the carburetor throat, since their
> open ends are in the high-pressure area underneath the
> tank cover. As speed increases, that pressure increases
> and the position of my legs was changing it ....
> snip <
> Gary Rathbun
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