I'm looking for some tips on carb tuning. What kit to buy? Should I or should I not drill the hole bigger in the carb? I have a 2005 sportster XL1200C and tomorrow I will be installing Avance and Hines short shots. Otherwise, the bike is stock.

 

I went with CVP performance carb kit. It has all the jetting you need and mods for the slide. Even if you have a stock bike it has listing for reccommended jet sizes
http://www.cv-performance.com/tuners-kits/

 

2nd that! CVP is awesome! I used them on my cv40 kit

 

Basic, premium, or deluxe kit?

 

I went with deluxe kit, just because for the price difference, if you need any gaskets etc the deluxe has them. Beats sitting around waiting for parts to show up. Oh and I bought basic carb rebuild kit so I could double check float level and have extra bowl gasket if I needed it.

 

If you're talking about drilling the hole in the carb slide bigger, don't do it. It can cause more problems than it fixes. Using a lighter weight slide spring is OK.

You should read THIS THREAD on jetting first before proceeding.

 

I have two carbed sportsters, 883 and 1200, both with one size up on the pilot (low speed) jet. That was all it took for smooth running with no popping - a size up even works fine with stock mufflers, they're tuned so lean from the factory. If you want to fine tune that for slightly better (maybe) performance, you can shim the needle, but I'd bet most people wouldn't notice the difference. Putting on lower restriction pipes (usually louder), may give you more power at high rpm, but will lose some grunt in mid range, where most of your riding is. Some guys disagree with that, but I think they're "hearing" the power more than feeling it. The experts and racers say just putting less restrictive pipes on loses mid range unless you match everything else to it and carb work alone won't do it. How much mid range loss? I could really notice it on my 883, not so much on the 1200.

The only drilling you want to do is a small hole in the plug over the mixture screw in the bottom of the carb; screw a self tapping screw into that so you have something to grip and yank the plug out. Drop the carb bowl for access to the jet. You can carefully pull the carb out of the intake manifold and rotate it to reach the bottom without disconnecting the throttle linkage, but you'll have to pull the enrichment cable (I loosened it from the **** side, left side of bike) and fuel line. This pic of my 883 shows the throttle still connected, plenty of access to the mix screw plug (already gone here) and jets.

 

I just finished my carb rebuild on 2006 1200C. My bike has 70k miles I have also been running V&h Shortshots. I went with all the CV Performance parts, very easy, great results. Use the jet recommendations they include with their instructions. I pretty much replaced all the parts with what they have to offer. No need to drill the slide!

I would start with the AF adjustment at 3 1/2 turns. Good luck!

 

Forgot to put this in the earlier post - that's the cheap and easy way to keep it running nice after you put a set of pipes on for looks and sound. The CV kit costs more, but is a good idea if you're going for performance, like going stage 1, and also if it's a high mileage bike with no carb work yet. Or don't mind spending the money for better quality.