carburetor jetting issue

[No1eman]

Howdy. I am new registering to this site. I used to read the old site alot, but didn't register. I decided to register because I wanted to throw a question at you guys and see what kind of info there is.

I have a 1995 FXDWG that has about 70000 miles. I have a kuryakyn twin velocity air cleaner, and last summer I installed some Python staggared duels. As a result of the pipes, I had to rejet my stock carb. I used one of those kits (dynojet, cv kit?). I had this thing apart and back together again at least a dozen times, and I'm still not confident that it is right. Right now, I have a .44 low speed jet and 170 high speed jet. I used the needle that comes with the kit, and have it adjusted with the e-clip so that the needle is one click lower than the center point. I also have the lighter spring that comes with the kit, and drilled the bigger hole in my slide.

my problem is that my bike tops out at like 80. Now I know that 80 is fast, but it used to do well over 100. I've fudged around with jets to get it so that my milage was reasonable, I now get just about 200 miles to a tank. at one poing it was like 150 miles to a tank.

At idle when I blip the throttle, it stumbles just a bit, I may need to go back to the 45 low jet. I get very little to no popping through my exhaust, and really good accleration. my top end is just low. Is that a lean or rich condition? Any ideas or thoughts? I really appreciate any info you can give me. I'd like to get my carb issues straightened out because I want to get a upgraded ignition.

[Norton Commando]

Your main jet controls fuel mixture at 80 mph. If your plugs have a sooty appearance after running at 80 mph for a mile or two, then you need a smaller main jet. If, howver, the plugs look bleach-white then you need a bigger main jet.

[choseneasy]

Or lean it up a bit by dropping the needle down with the clip. I think you have that set up a little high.

[Grayrider]

I would try going back to center with the needle clip, install the 45 low jet and as mentioned check your plug color. I think you are lean on bottom and top and need to go with a 175/180 main jet.

What happens at 80mph? Does it sputter, go flat or ? It should be in the 100 mph range if setup right!

When I bought my 97' Heritage [20,000miles on it], there was a 170 main in it as well. It would not top out clean. At top end it would sputter and backfire through the pipes, too lean! 
I have a stock CV carb, Kerker slip ons with a K&N filter! Also had a 46 low.
I dropped the low to 45 and increased the main to 175. Runs tits!
With 180 it would bog at top end! Too rich!
I have the n72 needle. No hesitation when I blip the throttle. 

[No1eman]

I would try going back to center with the needle clip, install the 45 low jet and as mentioned check your plug color. I think you are lean on bottom and top and need to go with a 175/180 main jet.

What happens at 80mph? Does it sputter, go flat or ? It should be in the 100 mph range if setup right!

When I bought my 97' Heritage [20,000miles on it], there was a 170 main in it as well. It would not top out clean. At top end it would sputter and backfire through the pipes, too lean! 
I have a stock CV carb, Kerker slip ons with a K&N filter! Also had a 46 low.
I dropped the low to 45 and increased the main to 175. Runs tits!
With 180 it would bog at top end! Too rich!
I have the n72 needle. No hesitation when I blip the throttle. 

Ok, I will try that combo. At eighty, the bike runs pretty smooth, no sputtering, just tops out low...Did you use the lighter spring, and drill the hole in your vaccum slide? What is n72 needle...my stock one isn't adjustable, that is why I used the one from the kit.

Thanks for all your help!

[RLPOS1]

 To start here is some info that might help: It is my opinion that all Harleys are jetted lean from the factory to help meet EPA regulations. This is why they will only run 80MPH and are so cold natured. When I bought my evo in 96 it was so cold natured that if I stopped for 30 minutes,I had to choke it to start even had I been riding for hours. I fixed this buy going to the Sportster needle and a 45 slow jet Now several years later and after Stage 1 and Stage 2 upgrades I have a 80 inch EVO with EV27 cam, Hypercharger w/k&n filter, Hooker 2into 2 upswept slash cuts, Cv carb with Thunderslide kit. I went with a 185 main and a 46 slow.  Bike runs great and still gets about 45 mpg.
I would start by obtaining a suply of mainjets "175/180/ 185/ 190" and slowjets "45/46/48"going back to the instructions (I here Thunderjet needles and tube work better with Thunderjet jets)and setting the carb up as suggested. My start would be a 45 slow with a 180 main and set the needle back to the position the instructions said.  Pop out the aluminum cap that covers the adjustment srew and get the Idle right.Then the easy way to get it close on the top side is to warm the bike up and get out on the hyway (where there are not any law enforcment)  and run up to about 4500/5000 rpm in fourth gear and hold it there for a minute then back off the throttle about an 1/8 of a turn. If the rpms go up you are still lean, if they go down you are probably rich. If there is no difference it is about right. if you have no tach you can tell buy the seat of your britches if it pulls harder or not. Check out  http://nightrider.com/ for good info on tuning your carb
Good Luck






http://nightrider.com/

[bobrk1]

I think your to lean ride around town and keep the rpm's down and check your plugs they should look the color of cardboard a nice tan, I ran a 48 low on my 97 rk. The main jet sounds to small too, at about 65 mph open the throttle wide open and count to 3 then back off about 1/8 on the throttle if you feel it pulling your to lean, I ran a 48 with a 1200 needle and 180 main. I did cam and heads and the dealer said they never go past a 180 main, I got a 50 low 200 main and when i ran it on a dyno he said it was real good but he still had me put 2 shims under the needle to bring up the mid-range, it takes time but you can get it real close like this, when you get the right main when you back of there will be no difference. Also did you pull out the plug on the idle screw? On the bottom of the carb in the back you'll see where the casting sticks out a little behind the bowl you can see the plug stuck in it, drill a small hole in the plug and stick a screw in the hole and pull out the plug, this you can use for your idle mixture bottom the screw out very easy then turn out 2 1/2  turns this should be close, if its popping go in or out it should stop.

[Grayrider]

I didn't change the spring but did drill! The other posts mentioned adjusting the mix, that's another thing that could affect your low end and the sputter.
Plenty of good info from the other posts and you will need to experiment to get it right! The n72 is a sportster needle and usually works good on the 1340 CV carb.
But, it will come down to where you are [altitude] and what the bike is doing for your specific setup! 

You should end up with a 45,46 or possibly 48 low and a 175/190 main with about 1 1/2 - 2 1/2 turns out on the mix screw!  Those are the general ranges to consider and work with for most 1340 CV setups and you should fall into that area when set.

But, your bike will dictate what it needs to run great!

Ride Safe!

[PaJoe]

If you get too frustrated send your carb to Wally in Sunbury Pa. He does excellent work and will have it set up pretty close to where all you do is bolt it on. All you need to do is let him know the details about your bike.

http://www.harleydavcvcarbrebuild.com/

I think it's about $145.00 to rebuild your carb or about twice that much for one of his rebuilt carbs.

[92Fatty]

I second the nightrider cv mod page. http://www.nightrider.com/biketech/hd_cv_mods.htm My setup runs the Sportster needle with a 45 slow jet and a 175 main. This is with a stock cam, longshots no baffles, and a hypercharger. I drilled the slide like it says to on the site but i didn't modify the carb spring. When you are talking about adjusting the clip on the needle that is dynojet needle and i can't help there. Factory needles have no clips so we use thin washers underneath the needle to richen or lean the needle. As for needle selection the N72s was from an older flh and was recommended by John S. I just ended up with the 88 Sportster N65c needle. http://www.nrhsperformance.com/tech_cvneedles.shtml
has info. Do you still have your factory original parts prior to changing the kit? 

[No1eman]

I second the nightrider cv mod page. http://www.nightrider.com/biketech/hd_cv_mods.htm My setup runs the Sportster needle with a 45 slow jet and a 175 main. This is with a stock cam, longshots no baffles, and a hypercharger. I drilled the slide like it says to on the site but i didn't modify the carb spring. When you are talking about adjusting the clip on the needle that is dynojet needle and i can't help there. Factory needles have no clips so we use thin washers underneath the needle to richen or lean the needle. As for needle selection the N72s was from an older flh and was recommended by John S. I just ended up with the 88 Sportster N65c needle. http://www.nrhsperformance.com/tech_cvneedles.shtml
has info. Do you still have your factory original parts prior to changing the kit? 

yea, my bike was stock...I had loud factory mufflers, but the aircleaner, and carb were untouched.