Here's the post that helped me set mine up
another 28/36 owner hurray!
first of all go to
http://www.southerncarbs.co.uk/ and give them a ring thats where I bought my chokes, and jets from and the guys there I found were very helpful.
I can only tell you what i know from running a 28/36 on my 998cc and that is that is was waaaay better than a single 1.5" SU and Twin HS2 (obviously my personal opinion but after tying all of them that is my conclusion). Felt more responsive, good economy, lovely sound when you have opened up both chokes.
with a 12g295 head, forged rockers, cooper freeflow RC40 puting out 61bhp and 61 lb/ft it was using
Primary Choke - 23mm
Primary Main - 125
idle - 45
air corrector - 185 (if not it was 180 or 190)
Secondary Choke - 24mm
Secondary Main - 130
idle - 45
air corrector - 185 (if not it was 180 or 190)
Pump jet 70
Emulsion tube F30
bleedback valve cannot remeber i don't think i changed it.
Best thing is to use the vizard chart to get an idea for bhp/secondary choke size and then either go 1mm or 2mm smaller for the primary. Southern carbs did a bit of a deal where I bought about 6 main jets for the price of 4 as when you go for an RR no one will have the parts so take a few sizes bigger and smaller with you. 70 is the biggest pump jet you can get so use it. Idles jets are not so crucial so i would have though 50 or 55 should be fine. Emulstion tubes are always as F30 as vizards sais. And as with the main jets get a few different air correctors, but on the whole Vizards guide of engine types to what jet you need is pretty accurate so use that as a starting figure and work either side.
A little thing to watch out for unless you have already fitted the manifold and carb is to make sure it does not foul on the exhaust manifold! i had this problem with my manifold which sits the carb 90 degrees to the line on the pistons. and depending on what air filter you use that it fits under the bonnet with a 45mm K&N it just fits under, though i had to counter sink the bolt/nuts for the filter so they did not protrude above the filter.
I hope this helps!
Edited by cap'n crunch, 02 November 2010 - 07:28 PM.
