CV Performance Carb upgrade

My XL1200R has just received a CV performance carb upgrade replacing the previous owners Dynajet set up. Generally speaking I am very please but still have the odd carb fart, usually blipping the throttle when coming down the gears. Other performance parts include SE2 slip on's and SE air cleaner.

The carb is jetted 46 slow and 185 main and pulls like a train from low revs (700rpm) and without any drop off throughout the rev range. When carrying out the fine tuning using the EZ screw fitment the engine will stumble on slow idle when I screw the EZ in but I can screw it as far out as I like and cannot get any change in the engine low idle note. These tests were carried out at an idle of 600 rpm.

Currently I have the carb set up with the EZ at 2 turns out from lightly seated and idle around 700 rpm and it never misses a beat. Should I just stop looking for perfection? In every other way I am very pleased with the performance.

Being a UK owner I run 97 grade fuel, the engine and transmission run synthetic lubricant.

If I am not mistaken, if you can have your idle mix all the way in and there is no change, you are way too fat on the pilot. I would suggest dropping to a 45 slow jet.

Others will chime in on this... Welcome to forum....

Hi JohnnyBiker and thanks for the welcome. Following the fine tuning instructiuons on the CV web site they say turn the idle mix in until the engine stumbles at slow idle which it does and then turn the EZ out until it stumbles again. When I turn the EZ screw OUT there is never any change in the engine note, it just runs at slow idle normally. Should I go down a size on the slow jet?

One other point to note is that the plugs never foul and are generally very light grey on the rear and close to white on the front even after a long run.

You are running the exact jet(s) that I am and I too have a 1250 Sportster. Mine has a lot of high performance work done to it and I am contemplating on going down one size on the pilot jet. (Down to a 45).

Yes, I think you should go down one jet size. If your rpms are not changing as you are adjusting, usually this is because of too large of a pilot. (too rich). Just my opinion, but 600 rpm idle is really low...

Don't take my word for this just yet, others with more experience WILL chime in to either confirm or tell me that I am an idiot. Probably the latter..

You do most of riding on the main jet so that is most likely good. The pilot is only good for idle and just off of idle....

go 2 1/2 turns out and bump the idle a bit higher you need to get air speed across the air bleed holes for fuel to flow out of the slow jet at a idle with the butterfly closed if idle is to low this will not happen a thus you will run a slight leaner 750 to 800 is a nice idle setting good oil flow and a slight lope at an idle we all want that evo sound but its not good for a sporty motor . good luck and ride safe 46 sloww should be ok for an air cleaner and slip ons . see ya limey !!!! ride fast and safe