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Re: Lift Throttle Backfiring

To: triumphs@Autox.Team.Net
Subject: Re: Lift Throttle Backfiring
From: Jeff Arrowsmith <jarrow@dlcwest.com>
Date: Wed, 30 Apr 1997 19:55:27 -0700
>Jeff-
>my 76 spit (california car with catalytic converter) came from a previous
>owner with weber DCOE (I assume 40. I should look at markings/measure the
>bores, I guess), has stock ignition with vac retard disconnected (also
>courtesy of a previous owner), currently timed at about 10° BTDC at idle,
>increases to about 20° BTDC at 2500-3000 RPM, runs passably when warm,
>acceleration lousy (step on it too hard and it seems to hesitate), do you
>have stock cam? what ignition? any suggestions?
>thanks
>Joe Schneider
>

Joe......here's what I did. I went out and bought all the manuals/tuning
guides on Webers I could find..........spent all winters reading about
these carbs and it helped. Webers are often misunderstood and misjetted.
These carbs are a work of art but can be very time consuming to set-up
properly to your specific application. If you don't have the time to tune
it yourself......find a local garage that has experience with them. Before
you start adjusting the carb make sure everything else is in proper order
(timing/compression/fuel-related/electrical).
 Personally the first thing I would do is get rid of the stock exhaust and
replace with a header and some sort of breathable exhaust (NOT MONZA:-)).
....then to the distributor......either replace with an aftermarket unit or
get the  stock dist. re-curved for more advance. That would be the LEAST I
would do with a DCOE.......from here the sky's the limit......rad cams/head
porting/intake work.
Oh I almost forgot.....change the fuel pump to a good electrical one and
add a pressure regulator inline. Just shout if ya have any more questions
or need help.


Jeff.A


1967 GT6 Mk1
1975 Spitfire
1975 TR6
===========================================
"Why do you own 3 Triumphs?".........because I can't afford 4!
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Rap = Disco for the 90's
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