Hi Folks:

I have a 2004 Fatboy with the standard 88TC. The only engine mods are the V&H longshots. Over the winter I plan to add an aftermarket A/C and to do a small cam upgrade when I change out the cam chain tensioners. I mean you're in that deep already, why not?

I recognize that I will need to change the jetting on the stock CV carb. Being a decent wrench, but never having worked on a carb I feel this is the perfect time to learn the basics.

What I would like to do is buy another CV carb and rebuild it and us it as my guinea pig so to speak. That way if I really screw it up I can at least return the bike to the original configuration and rethink my errors.

I have the service manual and I'm sure it will say but I suspect my bike probably has the 40mm version of the CV carb. I'll check that before buying anything.

So why am I telling you all of this? I need to know:

1) if there are any flaws in my plan.
2) Are there any gotcha items I should be aware of when looking for a used carb to rebuild.
3) Any one care to take a guess at what I should be looking at as a starting point for jetting?

I suspect my final setup will look like this, V&H longshots, V&H naked AC, S&S 509 cams

If you've stuck around this long... Thank you and thank you for any guidance you can offer.

 

Carb tuning is, at best, a compromise and trial and error.

I suggest that you stick with OEM CV parts and avoid the aftermarket "trick" kits like DynoJet, Yost, etc. Also check out the Nightrider website article on modifying/tuning the CV carb.

http://www.nightrider.com/biketech/hd_cv_mods.htm

You may need to change the pilot from a 42 to a 45 but will definitely need to go up on the main and shim (raise) the needle.

Look for the CYCO cam chain tensioners on Ebay; better and cheaper than OEM parts.

BTW, I have a CV 40 for sale; missing a diaphragm; PM me if interested.

 

when my bike is 88ci with andrews 26 cam and se eacle pipe i end up jetting at 46 and 190 with i shin under stock needle

and it ran better when i add up a daytona twin tech ignition module

 

Thank you both for the info. DJL you have a pm.

 

I have had good luck with the CV Performance carb kits. You may want to look there as well. There is a good tutorial on CV jetting there as well.

 

I've been wandering through that site. Thnx.

 

I have a CV 44 setup that I tried on my stock 88 and it was too much. Like was said, it stumbled badly when it was cold and when the throttle was opened quick. I put the CV 40 back on with a 48/190 jet combo with the N65C needle jet w/ two washers with 3 turns on the mixture jet. This on a Stage 1 SE a/c and SE Pro II Double Barrel pipes with open baffles. It warms up quick and runs great but it still idles a little rough for the first 20 minutes or so...