[hwbudden]

I have a stock carb on my Deuce. I've put on V&H straightshots, highflow air and rejetted the stock carb. What type of improvements would I gain by replacing the stock carb with a Mikuni 42? Would this be the next upgrade in my journey to more torque?

[ffflhtcui]

Just to add to your question......I'm curious about the difference between the Mikuni carbs of old and the Mikuni Easy, which uses the stock air cleaner and cables and just bolts on in place of the stock carb. Haven't heard any comments about this relatively new setup.

[hotroadking]

IMHO the only thing you'd do is lighten your wallet, the Mik is a very good carb, it has excellent throttle response, so it will change the way the bike feels, but power wise a stage 1 isn't IMHO going to perform any better than it would with a well tuned CV.

In fact the CV provides you with a better charge of air and fuel by the slide coming up as needed, so you open it all the way but the motor pulls 80% the slides not going to go all the way up keeping the air flow postive.

I'd spend my money elsewhere like a dyno tune upgrade to the cv40 on the bike now.

[voodoo1]

the mikuni is not based on constant velocity as a factory carb(CV) the jetting/idling is some what EZr to tinker(good and bad) with. if ya got idle issues you adjust the idle, you have slow speed issues adjustment is Ez to get to and if you have high end issues you deal directly with it. Jets are visible and the "flatside technolgy" is just that, different and a bit more adjustable friendly and responsive.... for everyone I have seen use them. However I agree you can get alot out of the ol' factory CV carb.. more than some are aware of so you might really wanna think about it,find out how far can you push/use that ol'CV before spending $400 plus to get a flatslide.

[beast]

Just installed a screamin' eagle 42mm (Mikuni) on my 80" EVO. Lot more responsive than my kitted CV. Better fuel encon. & a lot more pull. Money well spent in my opinion...

[CD]

Originally Posted by voodoo1

......before spending $400 plus to get a flatslide.

Huh? An easy kit runs $250.00 and works with any CV setup. The full kit runs more but is not really needed for a CV swap out.

The CV can be tweaked and will provide smooth throttle response. Think of it this way. The CV is like a radio that has a volume knob and a quiet to blast mode switch. The CV works like the volume knob smooth, linear increases and decreases in volume. The HSR or any butterfly carb. is like the blast mode switch. You can go from idle to full blast faster. BUT you better have your jetting right and know that you are the one in control of the throttle response. Otherwise, you will end up stumbling if you whack it open and the RPM is too low or the jetting is not right. That is the beauty of the CV. THe carburetor will only flow what the engine is demanding right up to the maximum it can flow. Properly setup, the CV works very well but has that rheoestat like throttle response. Some like it and some prefer the snappier response of the HSR or the S&S. An S&S or HSR will make a little more top end power but we spend very, very little time at 5,000 RPM or better.

[hotroadking]

Originally Posted by CD

The CV is like a radio that has a volume knob and a quiet to blast mode switch. The CV works like the volume knob smooth, linear increases and decreases in volume. The HSR or any butterfly carb. is like the blast mode switch. You can go from idle to full blast faster. BUT you better have your jetting right and know that you are the one in control of the throttle response. Otherwise, you will end up stumbling if you whack it open and the RPM is too low or the jetting is not right. That is the beauty of the CV. THe carburetor will only flow what the engine is demanding right up to the maximum it can flow. Properly setup, the CV works very well but has that rheoestat like throttle response. Some like it and some prefer the snappier response of the HSR or the S&S. An S&S or HSR will make a little more top end power but we spend very, very little time at 5,000 RPM or better.

I like that write up CD good example I've always said you ride a CV you drive an S&S/Mikuni

[voodoo1]

trying not to put down a Mikunni too bad..but yeah out here I just saw one in a kit from HD for around 400.00. The carburetor itself I just seen it go for well in the 200 range..(no kidding!!) I like the....... "ride the CV and drive the mikuni"... gonna go tell the fellas about that one!!!. the EZness to tinker with the adjustments is half the problem for some. Like it has been said a CV takes what it needs EZ enuough..just did not wanna have someone feel rooked for buying a flatside style carb, they do offer advantages.(none I want right now)

[hwbudden]

Thanks all for the input.
Lots of great feedback to my question.

[Big Ben]

The confusion about price comes from the fact that no one but Direct Parts sells them for that cheap, so if you do decide to buy one, buy it from CD
(I did.)

Everything costs more from your local HD dealer, and here in Japan, where they make the @$#% things, the EZ kit costs around $600!

I'm wondering if anyone can answer ffflhtcui's question about the difference between the using the EZ kit with the stock manifold and using the Mikuni manifold?

[hotroadking]

I had the HSR45 total kit on the 95 inch motor, it ran great, throttle response is great, when you opened it up, rev the motor a bit to get RPM's up and open the clutch, hit the throttle and you were gone, the feeling is great, however the dyno said, no more power than the CV44.

In respect to the manifolds, I used HD's CV44 SE intake it is a press fit vs the mikuni rubber flange, I had leaks and the carb would shift in the rubber mikuni flange when it got really hot. With the cv44 se intake the HSR45 fit perfectly, and you can get a larger rubber seal to run the hsr42 in the cv44 intake. The CV intake is a better shape IMHO as well, no step like the mik intake in the front.

Also, Joe Minton formerly of Mikuni Fame now of Jims Fame told me he felt the rubber flange would provide an oscillation to the carb causing the fuel to foam in the bowl, said he tried to get Mikuni to change it but they wouldn't.

Jap bikes with Miks that use that don't vibrate like a 45 V-twin so it's possible that could occure.

[Mojo-FTW]

Don't know if this helps, but I just put a Mikini 42 HSR on TC Nightrain and it just slipped right onto stock mainfold, it was great, and I love it. Course after I was smart enough to block off the vaccum for the petcock that I wasn's using anymore. Pretty happy with the HSR kit and it fit on, and required little tuning with igintion module, forcewinder and x-pipes.