Richard---You really are taking on quite a project in getting three, two
inch SU's sorted out. I'll start with the good news. Yes, there are
needles available to make this happen. Nearly ALL Su needles are thick
enough at the "idle" speed diameters to accomplish this.
I will recommend two books for you to get you started. The "Haynes
Workshp Manual for the SU Carburetor," and the second is called "How to
Power Tune the SU Carburetor", by Des Hammill. The first book will show
all of the needle selections, and the second, how to tune an engine
modified with SU's.
It would be sheer luck to stumble on needle choice that would satisfy
the engines needs at all rpms. At this point I would recommend that you
spend around $150 for an oxygen sensor, (or two or three) to place into
the exhaust downpipes, to feed information to an Air/Fuel monitor. (K&N
makes a kit) Such information that the 02 sensor provides will let you
know how close you are to the proper mix. Too lean or too rich and you
will be defeating the purpose of changing the carburetion system.
Tell me what needle you now have installed, and I can maybe get you in
the ballpark. The letters will be stamped on the shank.
Dick
|