Mikuni-Really Faster Throttle Response?

[Flat Dog]

Is the HSR true to its PR hype that it really give faster throttle response over a CV? Also, can jets be purchased at just about any jap bike shop?

[fuzznut5197]

Yup, a properly tuned Mik will have a quicker transient throttle response than a CV. Some of it is from the Miks shorter lock to lock throttle travel, the rest from its slide design. Years ago, I swapped a CV40 and HSR42 back and forth a couple of times, and the CV throttle response felt "fluffy" compared to the Mik. But the Mik has a downside in that you can't crack the throttle open all the way under 3-3.5krpm or your torque will suffer from lack of velocity.

[Flat Dog]

Even with ported and flowed remorked heads, fuzznut? I would think that with the hot heads, the velocity should be ok vs the ~38mm venturi of the stock CV.

I had to edit my post for a misspell-I also meant to ask if jets/parts can be bought at your local Honduh/Kawkasaahkeee dealer. Anyone know?


Thanks!

[fuzznut5197]

Even with ported and flowed remorked heads, fuzznut? I would think that with the hot heads, the velocity should be ok vs the ~38mm venturi of the stock CV.

It's not the velocity of the heads, it's the carb design. When you open the throttle on a CV, there is a delay until the vacuum slide readjusts itself. We're talking milliseconds here, but it's enough to be noticeable when you directly compare the two carbs.

Don't know about the metric dealers, but there is no shortage of parts availability for these carbs.
Pretty much every H-D aftermarket book has them.

[Mark222]

Yes, it is true.  You will notice a difference.  I was sceptical too, but it was immediately noticeable.

Mark

[bigtone]

If you drill out the bleed hole and/or change the spring in the CV, the difference is much less. Some people claim they've had problems after enlarging the hole, but I haven't with any CV's that I've done.

[Reddog74usa]

John, It all depends on what you prefer but I like the mikes. Great response, easy to tune and easy to get parts for. Heck befor long H-D will be listing the cv's as obsolete.

[Flat Dog]

I'm hoping the stock jets/needle will be cool, but it will be nice to stop by a local rice shop rather than riding 30 miles to the stealership for carb jets while I am getting a general tune dialed in.

[Gonzo]

I wouldnt go back to the CV after running a Mik. World of difference. The only drawback is the "mikuni rattle". Especially if you run an open element like I do.

[Sonny S.]

I do a lot of touring and the CV does happen to be great for maintaining AFR at various altitudes.
Mik will give you better throttle response though. The Mik is easier to tune but I'd much rather swap needles in a CV.
IMHO the CV is a smoother running carb because of it's later throttle response.
If performance is strictly the goal I'd say the Mik is best.

I must admit I'm partial to CV's. I've got (1) CV44 (7) CV40's and (1) Mik42 

[Reddog74usa]

I agree with Sonney. The cv is the smoothest running carb. I had a underground build that produced 118TQ and 110 HP with a cv44 properly jetted so it's a toss up. The mik will give you a liitle more throttle response and seem crisper but the mik will run smoother. Both carbs do well in high altitude touring as I had my RK with a mike 42 over independance pass in Co. at just over 12k feet with nary a cough.

[TarheelFXR]

Just my thinking, DO NOT DRILL A CV.

T

[Sonny S.]

I

Just my thinking, DO NOT DRILL A CV.

T

For many years I've drilled CV slides. I've also beveled or radiused the front edge.
Never saw any improvement by doing so but it became a habit...... I kicked the habit 

[hrdtail78]

Mik parts might be hard to get at a local Honda shop.  Different carb than what they have.  MidWest got rid of S&S and only deals with Miks now.  Any midwest dealer can get the parts for you.  Even Jireh.

[ClassicRider2002]

Hey here is another topical discussion on the matter perhaps this would make the CV Carb a bit faster offsetting the change to a "MIK". 

THROTTLE RESPONSE FOR EVOS "ALPHASAMUEL" <~~~CLICK, VIEW, & READ

At the end of the day......in a side by side comparison....I too have heard that the "MIK" is a faster throttle response compared to the CV Carb.....but you guys talk about getting these "MIK's" "dialed" in.....and it seems it's not always as easy as one protrays it to be......

What's a "MIK" costing these days.....$_______?

So what about Samuel's "tip" above?  Any good?  Any of you made such a modification?

I am thinking about doing this to my 99 FXR2.

Regards,

"Classic"

[Sonny S.]

Here is where I buy Mikuni parts. Anything you want.


http://www.mikuni-foxdist.com/

[Flat Dog]

I was just hoping to find a local source compared to mail order. Ends up my indie helping me build my motor has several full sets in stock, and I ordered a few more with my latest Zippers order.

Thanks!

[Sonny S.]

I was just hoping to find a local source compared to mail order.

......but I don't know where you live ...lol 

[Flat Dog]

Kinda in the boonies, and also in a dark place in my mind.  lol

[IN SEARCH OF]

Definitely the Mikuni has quicker throttle resonse. Very noticeable with 10:5 to 1 compression ratio.

[Blazing Saddles]

Had an S&S - "E" on my 80" build and now have been running a Mikuni on my S&S 107. Gotta say I really like the Mikuni alot more than the S&S - I've never run a CV.

Blazin'

[hbkeith]

had a wore out hsr42 on a built 80" evo,wouldnt idle but when you twisted it it was all there,changed it out for a new S&S E,noticed big difference ,hell of a alot more responce with the hsr,but i like the S&S ,easy to tune etc.if i was building a bike for the strip only it would have a HSR

[Flat Dog]

Already I love it just for the easy idle adjustment feature, and awesome throttle response.

[ramcr913]

Not trying to hijack, but I have a question regarding Mikunis-
I put 2 Mikunis on my wife's Beemer sidehack rig. They run great- easy starting, smooth idle, no flat spots... but the fuel consumption increased significantly. I would have thought the mileage would get better. Thinking about putting a Mikuni on the shovelhead, anybody with one installed noticed  a difference in fuel consumption?
I posted this in the shovelhead section as well, but the same question applies to my 97 softail- no issues with the stock CV but I may bolt on a mikuni anyway.

Thanks

[Flat Dog]

IMO the carb comes jetted fat for most bikes. Some tuning is necessary, as with any carb.