2001 FXDXT Carb Frustration!!!!!
Road Warrior
Joined: Oct 2010
Posts: 1,554
Likes: 52
From: Ottawa Canada
Hows the rubber diaphragm in the accelerator pump, make sure to look at it from both sides as it is the underside that will go bad, I had one that was falling apart, bike would barely accelerate
Stellar HDF Member
Joined: Feb 2013
Posts: 3,072
Likes: 1,727
From: Dallas, Texas
A mix-match of carb internal parts will make you nuckinfuts! Problem is you don't know who made what. The Trial & Error really sucks. D-jet & CVP parts aren't all that great. CVP does have good usable stuff, if you know which ones to use. The CV 40 is a very simple carb to tune. Make sure the manifold to head seals are good along with the carb to manifold seal. A vacuum leak will give you tons of trouble. I use the Yost Power Tube with supplied jets. Yost uses OEM Harley jets. Check the float setting, it is critical. Check the accelerator pump and make sure it squirts when you twist the grip. The Yost kit comes with needles that match the emulsion tube. The adjustable needles use the 3rd groove from the top. Place 2 washers UNDER the e clip. Place 2 or 3 washers ABOVE the e clip. The washers on top of the e clip eliminates the free play in the needle valve. Mixture screw - 2 3/4 to 3 turns out. IF the mixture screw packing is bad - CVP does have a good kit.
I started from scratch. 96 Street Bob - EFI. Converted to CV 40 - from a 92 Evo Softail.
I started from scratch. 96 Street Bob - EFI. Converted to CV 40 - from a 92 Evo Softail.
Outstanding HDF Member
Joined: Dec 2012
Posts: 2,557
Likes: 235
From: Texas
I had a leaking accelerator pump diaphram on my CV40 and after the rebuilt, I had a bear of a time getting it retuned with the CVP stuff that some PO had installed in it...it was all out of whack. I finally gave up and replaced the tube, nets, and needle with HD parts and readjusted the float and put a couple of shims on the needle to get it running smoothly...I had put a CVP mixture packing kit and EZ adjust screw but the EZ adjust screw would not adjust right and only caused me more problems so I went back to the original one...I ended up running an HD 185 main with the OEM emulsion tube, an HD 45 idle jet and the old Sportster jet needle with the float adjusted just a little on the rich side...and now it runs great!
Outstanding HDF Member
Joined: Aug 2009
Posts: 2,938
Likes: 4
From: NC
My setup is as follows, and if your bike runs bad with this combo then something is wrong like, a Dynojet slide, ripped slide diaphragm, incorrect float height, or a bad vacuum fuel valve.
REPLACE that DYNOJUNK slide, NEEDLE, and Spring with stock parts. That stuff is garbage, and is your problem. Order a CVP stock replacement slide, spring, the CVP emulsion tube, and either their velocity needle or N65C needle, mine as well get the nice idle screw, and fuel screw, with packing kit as well. The carb will work properly after these parts are installed.
I would also like to say that if you cant get a CV carb running correctly I would HIGHLY recommend avoiding a Mikuni HSR42, because you need to master CV carb tuning before you ever try and tune a HSR carb. The HSR carb is a much better carb due to unlimited adjustments, and for the same reason will confuse someone that doesnt have a firm grasp on tuning carbs like the Keihin FCR or Mik HSR carbs.
Get a service manual, disassemble your carb, post pics, and let everyone guide you on the steps to take during assembly. The CV carbs are great carbs and run better than a poorly tuned HSR all day.
Screamin Eagle Air Intake,
S&S 510 Gear drive cams,
Thunderheader
Sea Level, High Humidity Levels, and Temds over 80f all the time.
45 Pilot,
Float Level set exactly in the middle of the spec.
195 Main
N65C Needle NO shims
Slide drilled to 5/64
Stock Slide Spring
3 Turns Out on fuel screw
REPLACE that DYNOJUNK slide, NEEDLE, and Spring with stock parts. That stuff is garbage, and is your problem. Order a CVP stock replacement slide, spring, the CVP emulsion tube, and either their velocity needle or N65C needle, mine as well get the nice idle screw, and fuel screw, with packing kit as well. The carb will work properly after these parts are installed.
I would also like to say that if you cant get a CV carb running correctly I would HIGHLY recommend avoiding a Mikuni HSR42, because you need to master CV carb tuning before you ever try and tune a HSR carb. The HSR carb is a much better carb due to unlimited adjustments, and for the same reason will confuse someone that doesnt have a firm grasp on tuning carbs like the Keihin FCR or Mik HSR carbs.
Get a service manual, disassemble your carb, post pics, and let everyone guide you on the steps to take during assembly. The CV carbs are great carbs and run better than a poorly tuned HSR all day.
Screamin Eagle Air Intake,
S&S 510 Gear drive cams,
Thunderheader
Sea Level, High Humidity Levels, and Temds over 80f all the time.
45 Pilot,
Float Level set exactly in the middle of the spec.
195 Main
N65C Needle NO shims
Slide drilled to 5/64
Stock Slide Spring
3 Turns Out on fuel screw
I would also like to note that the fuel screw seems to carry over much farther into the pilot circuit then I have ever experienced with any other carb. This may be attributed to a fairly small single carb on a large displacement engine.
I installed the 48 Pilot, reset fuel screw to the 1.5 turns out as it was from the factory. 90F Temp 70% Humidity. Primed the fuel valve with a vacuum pump, and fired the bike.
Took about 15 seconds on choke, then about 10 seconds on high idle using the cruise control. Then it would idle well on its own, and would lumpy idle for a few minutes. I went riding and seemed to catch every stop light, eventually my idle ended up at 1300 which is a tad high so I stopped and gave the idle screw a slight adjustment. This may have been due to the fact that I switched to SAE 50 wt oil because its always so hot here, and the oil took much longer to thin out. Rode for another 5 miles and the idle again seemed to hover at 1300 so I gave it another slight adjustment. I may loosen the fuel mixture screw another 1/4 of a turn if my idle doesnt stay at the 1200 RPM that I prefer. Hot starts, just hit the button, dont touch the throttle and the bike goes to a nice solid idle.
Last edited by parts eeter; Sep 2, 2014 at 02:53 PM.
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