I have a 94 fatboy with alot of aftermarket proformance parts instaled I.e. top end job done, crane cam, crane racing ignition module, python 2 exhaust , hyper charger and a modifyed cv carb. The mechanic told me to switch carbs and go to a mikuni hsr42 mm. What is yalls take on this decision is it going to net me more power or just drain the pocket book

 

If the CV is modified correctly, you should be fine. That Crane ignition isn't giving you any more power either. I've found SE dual-fire is just fine and more reliable, as the Crane coils didn't last long for me.

 

I wouldn't put a Mikuni on it.. I would go with S&S "E"

 

If the stock carb is a "42mm Keihn" then what do you gain? There is a carb person by the name of Joe Minton, try to find his articles or go to knightrider.com for carb mods. The keihn can be a performance carb, so says Joe. A 44mm may give you the performance you are looking for.

 

Is it running good now? If so why switch.

I can guarantee you the Mikuni will suck more fuel. I can't get anymore than 35mpg out of one. I'm about to rip mine off and go back to a CV. I get 45 and 55 out of my other bikes running bone stock CVs.

 

Thanks for the replies so quick. I'm kinda in the dark about my bike seeing I was given it from my father who has alzhimers and can't give me much info. How do I know if its a 42 mm keihn or not from all my research I do know it is a keihn has the k and bar and sheild on it. I know my pops put a yost powertube and had some other stuff done to it but that other stuff i don't know

 

As fars as runing good oh god yeah sat In the garage for 7 years on a jack. Changed the fluids put good gas in and a new bat she fired up instantly runs like a b***h only thing wrong so far is a leaking left fork seal which is on order now. This bike has always been a work in progress adding something here or there since he bought it just trying to keep the tradition going it only has 30k miles.

 

Run it like it is for a bit and see what she does. Check your mileage with the CV. The Mikuni will have better throttle response. But not worth the drop in mpg to me.

 

Pay attention here good advice , a properly setup CV with a new slide will give you the same as the Mikuni for $300 less , on a basically stock bike it's plenty .

 

I had a bunch of work done to my CV carb on my 99 RK. That carb must have been off the motor 10 times, Jets, Thunder jet kit, then a Thunder slide, then the Stock slide was smoothed out by a race tuner replacing the composite Thunder slide that never did work right, and the carbs bore was polished. Long story short, too many hours into a carb (the phrase "beating a dead horse" comes to mind) Then I finally gave in and swapped it out for an HSR 42 Mikuni. World of difference as far as power goes plus it has a much smoother powerband. Do what you want as far as the advice you're getting, me personally I'm done with CV carbs. I've had that HSR 42 on the RK now for about 6 or 7 trouble free years. Back when I bought the Mikuni it was like $299 for it. I think they went up. I have older Harley's that have S&S Super E carbs on them. Pretty basic crude carburetor. They work, nothing to write home about.