Need help from CV guru's

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Dec 23, 2007 | 11:39 AM

Lee n Tj

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Need help from CV guru's

Have a 93 Ulra, I have put in EV-27 cam, Jim's lifters,adj. push rods,single fire, Sampson true duels with rolling thunder exhaust,K&N filter,new rings and base gaskets,new exhaust and intake gaskets and had the CV carb set up. At that timethe Indythought the carb was kinda between 2 different high speed needles, so he went with the smaller of the 2 and said ride it. The bike has 5K miles since work. it runs great plugs look perfect. Now for the small problem/question. When I accelerate if I shift before 3k you really do not notice anything, but if you wind it out a little longer and shift between 3200-3500 I get a slight top end valve rattle?, and the bike feels like it is being held back (as though pulling a trailer say),grade or brand of fuel does not make any difference. . But, if I pull out the enrichener (to the point just as the idle rpm's would start to come up) the bike accelerates with less strain/easier ( as thought it is no longer being held back. So is it asking for a size bigger needle or do I need to adj. the pump rate of the carb as suggested bya riding buddy? He thinks it is not feeding enough fuel in as it comes up in rpm.(mid range)Hate to take to the indy for something I could do myself, but I have very little knowledge of CV carbs.

Dec 23, 2007 | 01:48 PM

justlookin

Stage III

Joined: Nov 2007

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RE: Need help from CV guru's

Find out what jetting is and look at going a size or two up. Jetting charts for Oem bike set ups are for just that. Better cam/ exhaust/ ect = better breathing more fuel needed to support demand.Some timming issues will act simlar.Some techs know quite alot but not every set up is the same. Also in some applications a intake leak creating a lean codition.There are many different things to look for. Hope some of this helps

Dec 23, 2007 | 03:16 PM

miacycles

Elite HDF Member

Joined: Sep 2007

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From: Bluffton, South Carolina

RE: Need help from CV guru's

Bigger needles give you less fuel. Try going two steps richer with your main jet. If problem gets worse than go two steps leaner from original. That should get you going. Before you do any jet changes check your float level, needle and seat(may be some debris that is slowing down fuel flow)and fuel filter if you have one.
Your problem may also be in the way your carb was "set up" many shops drill out the slide hole too large and it opens up quicker than it should causeing a drop in vacum resulting in poor performance.

Jan 1, 2008 | 10:00 AM

grbrown

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Joined: Jun 2007

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From: Bedford UK

RE: Need help from CV guru's

The rattle could be in the cylinders due to ignition, not valves. I have had it recently with my bike! Probably caused by the spark-plugs getting very hot and pre-igniting the mixture.

The other guys have given tips which are all good stuff, but I suggest starting be ensuring the inlet manifold is sealing properly at the heads and working your way out, checking all the other things as you go.

My problems proved quite complicated and I am changing my carb for a Mikuni, but it is not essential to go that far.

Jan 20, 2008 | 08:36 AM

shartflhs

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Joined: Jun 2007

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From: Cromwell, CT

RE: Need help from CV guru's

I have a similar setup to you, with the ev-27, single fire, but with v&h longshots in a 91 flhs. I found the stock petcock to be a restriction and changed it for a pingle. As far as the CV goes, i would make sure you have a 45 pilot jet and between a 185 and 195 main jet. If you dont have a dynojet kit get one or even better a thunderslide kit. This has worked great for me. The motor is now up to 96" and still the same carb setup. People have said it is one of the fastest dressers they have ever seen. Dont know about that but it keeps a smile on my face.

Steve

Jan 20, 2008 | 11:34 PM

Outstanding HDF Member

Joined: Mar 2005

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From: Darlington WI.

RE: Need help from CV guru's

Here is a good place to look for some tuning help

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

Jan 22, 2008 | 09:06 PM

92Fatty

Road Master

Joined: Jan 2008

Posts: 1,187

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From: Montgomery, AL

RE: Need help from CV guru's

I used the site JB posted. Niterider's tech tip worked great. I did it like they stated. Best recommend for ya would be pop it off and see what needle is in your carb and if there are any washers under the needle. I run the 88 sportster xl needle with a 45 175 setup on mine. My motor is stock setup except for air cleaner and longshots. I'll be upgrading to a VT3020 in the next couple of weeks after i finish up my inner primary leak. Then she'll be ready to go. Kent

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