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[6pack] SU needle for TR6 Conversion?

To: "6pack" <6pack@autox.team.net>
Subject: [6pack] SU needle for TR6 Conversion?
From: "Tomislav Marincic" <tomislav.marincic@earthlink.net>
Date: Wed, 4 May 2011 15:12:41 -0400
I'm thinking of switching to SU carbs on my TR6. Moss sells the conversion kit 
with the BAG needle, presumably for the stock TR6 engine.

Has anyone played with the needles already and found a better one to start with 
for a TR6 with the usual mods? (9.5:1 CR, GP-2 cam, header/exhaust, flowed 
head, 1.65:1 RR)

As a reference, I've tried 4 needles in the ZS carbs:

B1E (jag) :pulled like crazy above 3k, totally undriveable around town (rich). 
Would not idle.
B1AQ (stag) better around town, still too rich. Lumpy, high idle.
B1AF (TR6) Nice consistent idle, too lean above 3k, pings from 2200-3000 at 
more than 1/2 throttle, no power above 4k

I'm currently running B2Y (TR250) needles that I converted to adjustable-type 
by using the needle housings from my B1AF's. The idle is good, the plugs are 
whitish-tan, but the car still pings 2200-3000 RPM unless I retard the timing, 
and the power above 4k is not what it should be for a modded engine. I know the 
engine is capable if much more.

I'm betting that SU's with adjustable jets would give me a greater range of 
adjustment and a wider selection of available needles. I'd also like to 
eliminate the variable of the temperature compensators on the ZS.

I'm sure some of you have been down this path? Any tips?

Cheers, Tom

www.triumphowners.com/735
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