Hi all,
Trying to get my Solexes' tuned. Seems that the jetting on those puppies is
a little bit of a mystery to most owners. Seen a couple posts requesting
jetting sizes, and no responses. Possibly because the ventura's can be
different too?
For those that are interested, I am running 60 pilot jets, 150 fuel, 180
air, 35 pump and a 160 starter. I have later style 44's. Not sure of the
size of the venturas (:-( ). I have a .030 bored, 2000 (69 vintage). The
camshaft is the standard Solex cam (it was reground because it was scored,
the shape was maintained and the value geometry seemed fine. The head was
cut .010 to clean it up (as measured by Tom's size stats). The engine has
less than 5k on it since it was overhauled.
I am also running 50mm horns under ATG foam air filter.
I suspect that the 35 pump is too small, but haven't had a chance to
confirm (I have a set of 45's to go in). I was running 57.5 pilot jets,
with a very rough idle. Going to 60's was a definite improvement. I was
also running a 140 fuel and noticed some lack of power on the top end (the
engine hit the wall at 6000RPM). Changing to 150 fuel allows me to red line
it without any problems.
Although the carbs still need some fine tuning, (idle screws were not
changed when I went from 57.5 ->60's, but I believe that they are still
well balanced), I am getting backfiring (frying bacon with some snap,
crackle, and POP!) when I let off the gas and decelerate. I was under the
impression that tail pipe backfiring was a sign of rich mixture. Didn't
want to step down my fuel jet (it backfired on 140's too), so I tried
increasing the air jets to lean out the mixture. With 220 airs, didn't lose
top end RPMs, but the backfiring didn't let up (maybe a little), and the
idle became slightly rougher.
So does anybody have any suggestion on what I should try next? My default
is to go back to 180 air, and put the 45 pumps in. Then I could at least
tell whether it changed the backfiring/acceleration characteristics.
Other things I known I need to check:
1) float height, (their close, but I suspect not right on.)
2) There may also be some exhaust leakage between the front pipe and the
header.
Either of these problems a likely suspect?
Regards,
Mark
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