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Speed
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Discussion Starter #1 (Edited)
Am I better off ditching the CV with Dyno Jet and going with a Mikuni 42? I am running a Stage 1 TC 88. Eventually, I will probably go with a high torque 95 cu in build.

My friends say the Mikuni is the only way to go and I should upgrade. Two have Evos with Mukunis and one has TC88 with Mikuni.

I was always under the impression that the stock carb was a good carb when properly tuned. Also, the carb only really needed to be upgraded when you went with a bigger motor.

Will I gain power with a TC 88 by going with the Mikuni 42 P/N 29641-99? How big of a build is it good for?

What about the Mikuni 45 P/N 28040-02? How big of a build is it good for?

Thanks for the feedback,

Kevin
 

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The stock carb is good but the throat size will always limit it's ability to perform with a large motor. I'd swap carbs but I'd use S&S. American made and engineered, simpler to tune properly and anyone, anywhere could help you if stranded. S&S is a better carb all around than the Mik.
 

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Speed
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Discussion Starter #3
calcustoms said:
The stock carb is good but the throat size will always limit it's ability to perform with a large motor. I'd swap carbs but I'd use S&S. American made and engineered, simpler to tune properly and anyone, anywhere could help you if stranded. S&S is a better carb all around than the Mik.
Interesting...Thanks for the information. No one has recommended the S&S to me before.

KL
 

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calcustoms said:
The stock carb is good but the throat size will always limit it's ability to perform with a large motor. I'd swap carbs but I'd use S&S. American made and engineered, simpler to tune properly and anyone, anywhere could help you if stranded. S&S is a better carb all around than the Mik.

I totally disagree, swapping out a stock CV for an S&S is a step backwards. A tuned CV outperforms an S&S in every aspect and greatly outperforms it in many areas. If you have a bigger engine a bigger CV is avaliable. A Mikuni will give you higher HP numbers than a CV but is outperformed by the CV in the midrange.
 

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HD Tech said:
I totally disagree, swapping out a stock CV for an S&S is a step backwards. A tuned CV outperforms an S&S in every aspect and greatly outperforms it in many areas. If you have a bigger engine a bigger CV is avaliable. A Mikuni will give you higher HP numbers than a CV but is outperformed by the CV in the midrange.
Your right to disagree but we've tested all of those carbs on both HD and aftermarket motors and found the S&S carbs to outperform all of the others. The easy tuning aspect is also a plus for the home installer.
 

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HD Tech said:
I totally disagree, swapping out a stock CV for an S&S is a step backwards. A tuned CV outperforms an S&S in every aspect and greatly outperforms it in many areas. If you have a bigger engine a bigger CV is avaliable. A Mikuni will give you higher HP numbers than a CV but is outperformed by the CV in the midrange.
Agree. Take a look at Woods carbs. In comparisons on his site, the Rebel outpeforms the Mik. Other comparisons show the CV and Mik are pretty comparable overall. The Mik has crisper feel. The CV automatically compensates for changes in altitude. Consider how you ride and the way you'll use the bike.
 

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My limited experience has shown me that a re- jetted CV40 with a Woods needle (K1) is much better than stock and did well on my 95 c.i. with SE203 etc. A step change came ( along with heads, cams, V&H ProPipe) when I installed the Dakota Kid 42 mm CV, a bargain for about $300 + shipping. Excellent throttle response, good cold and hot starting and flows better than the SE CV44 (some folks actually measured both on a flow bench), no issues with high altitude riding, no carb farts, no backfiring. Took some time to find the right needle position. Great carb and a true alternative to the multi-circuit Mikunis.

PS: I will use this carb on my 107" build with a SE big bore manifold.
 

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Life is what you make it
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I think the Mikuni is a good off the shelf easy for the installer to use. No fuss no muss, "safe", and provides a difference you can feel and see on a dyno chart. I am sure there are lots of other ways to achieve the same or better results, but you may have to work harder to achieve it?
I have had two Mikunis worked right out of the box basically other then a jet change. IF I was looking for all out max performance I would be looking at a Bob Woods Carb.
 

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I've ridden the stock CV , rejetted stage I CV and the HSR 42 , I prefer the Mik for it's quicker response and to my seat of the pants better performance, I also managed better mpg with it.
 

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IronButt
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FOR max performance you are hard pressed to beat a S&S but for normal use and street manners the S&S is on the bottom of the list. I know that they are S&S fans out there but I am not talking about adding 3 thunder jets two external air bleeds and so on. The CV will be the best bet for all around use, if it was not why is that it isused on so many stock bikes not just hd but imports as well?? The drivabilty is what most people look for. Yes Miks are nice carbs but I have dyno'd just about everything out there including typhoons and for street use very hard pressed to beat a prepped CV.
That is my opinion and 12+ years tuning and it is woth just what you paid for it HA HA . Not trying to be a smart a$$ just that I have so many people struggle with the tuning and problems that the cv's just do not have.
 

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KLars1 said:
Good points guys. Is the Mikuni throttle response always going to be better than a prepped CV? I LIKE throttle response!
Try a reworked CV from Woods or Dakota. Throttle response on the Dakota is excellent, all I can say
 

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On a stock or mild mod 95, a well tuned CV will stand right up to a Mik42. You may gain a couple of ponies on the top end, but the graphs will be practically identical for both part throttle and roll on dynos WHEN TUNED CORRECTLY. And yes, we have tested them, also. Like Vienna Hog says, you really want to get the most out of a CV? Have Dakota Kid re-work one for you and you won't want anything else unless you go real large cubes or radical 95 mods.
Take it for whats it's worth, all we do here is work on snowblowers and weedwhackers!!! ;)
 

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calcustoms said:
Your right to disagree but we've tested all of those carbs on both HD and aftermarket motors and found the S&S carbs to outperform all of the others. The easy tuning aspect is also a plus for the home installer.
When the S&S first came out with the Super E in the early 90's it was a Godsend. It was the best aftermarket carb out there. About the same time Harley tossed the Kiehn butteryfly in favor of the CV. The 40mm Mikuni became avaliable shortly after but had a lot of serious shortcomings. Mikuni seemed to have paid attention to all of this and issued the 42. They have made running improvements too. People started messing around with the CV applying knowledged aquired from earlier CV type carbs such as the SU, some worked, some didn't. We ended up with 3 very excellent carbs compared to what else is currently avaliable. I've experimented with many different carbs including these three on my own bikes, living with them so to speak, as well as countless dyno runs and customer installations. In 7000 rpm peak HP scenerio comparisons the Mikuni 42 seems to have the edge, followed closley by the CV, then the E but they are all very close. But that's not the performance range the average person is looking for. When speaking of tuning it is not just a matter of setting the carb up and it runs good for the rest of the day. A carb that is easily tuned is one that can be set up once, starts well, idles smoothly, has good throttle response, pulls hard through the entire midrange at WOT, steady cruise, and all points in between, does this just as well on a 34 degree day at sea level and a 104 degree day in a high Rocky Mountain pass and will do all this for years without being retuned. The only carb that will do that is the Kiehn CV.
 

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I had the unique opportunity to try a comparison between all 3 (CV, S&S, Mikuni)...my '04 Softtal Springer of course came with a CV. 10K with it stock (rejetted for stage 1) before tweaking for better performance, never really liked it as much as I thought I should but good wrenches tuned it on a dyno. I was looking for a different carb when a buddy happened to inherit both an S&S and a Mikuni of which I installed the Mk 1st...really good throttle response but it seemed to be lacking in the top end, I next bolted on the S&S "E" and got it tuned. The response was as good, maybe a little better than the CV but not as good as the Mk, the top end was smoother, better power and I had no more "cough" unlike bothe the Mk and the CV. The tuning is extremely easy too. JMHO
 

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Speed
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Discussion Starter #19
GRock said:
On a stock or mild mod 95, a well tuned CV will stand right up to a Mik42. You may gain a couple of ponies on the top end, but the graphs will be practically identical for both part throttle and roll on dynos WHEN TUNED CORRECTLY. And yes, we have tested them, also. Like Vienna Hog says, you really want to get the most out of a CV? Have Dakota Kid re-work one for you and you won't want anything else unless you go real large cubes or radical 95 mods.
Take it for whats it's worth, all we do here is work on snowblowers and weedwhackers!!! ;)
Is Dakota Kid and Bob Wood the same person?
 
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