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CV 40 Needle jet

8K views 15 replies 2 participants last post by  Maxz695 
#1 ·
I removed my emulsion tube today and the needle jet came out with it. Never happened on my other carb. Can someone tell me which way it faces? There is a round edge and a flat edge. I have the flat edge facing up towards the piston needle and at idle when throttling I now sometimes have a cough but no all the time.
 
#5 ·
I went from a 46 slow jet to a 48 but it is old and may be a bit dirty I'm going to run some Gumout in the gas today. I also have a 170 main which isn't to bad but discovered the 175 is stock for my year 1993 883. The air mix was almost 4 turns out with a 45 and 3 + turns out with the 46 slow jet it is now between 2 1/2 1nd 3 turns out with the 48 jet. The carb is in like new condition at came off a v twin with cruise control. I removed the cruise control bracket to get it to fit.
 
#6 ·
#48 is good if you have a high flow exhaust and air cleaner.
Two other things to look at, the float needle and the enrichener valve. Pull them both out and inspect the Viton sealing tips. If there's a visible ring on either they're leaking fuel, bypassing fuel when seated. That will mess up the jetting !
For a carb to function correctly everything needs to be to spec. and no air or fuel leaks.
 
#7 ·
Yes I just swapped a set of 1 3/4 drag pipes not long ago and they seem to have just a tiny bit more clearance as my baffles where hard to get out of the old set and fit somewhat loosely in the new set.I do have a K&N High flow AC. I changed the enricher cable not long ago. True the needle itself is from my old carburetor it is a bit longer than the new needle that came with the kit. I installed that one on the old carb I sold. Turns out I have been running 15 lbs of air in my front tire and just pumped it up to 40 PSI and what a difference. It only popped once at a stop when hitting the throttle today I just got back and other than that is running top notch. Hopefully it will clear up. I can feel it could use that 175 main jet though and will order it along with a NEW 48 slow jet. Thanks for the tips and the help.
 
#8 ·
OK I need some smarts here. The carburetor I have on my 1993 883 XLH Hugger is off a V Twin (newer style bike). It had a cruise control bracket I had to remove to make it fit between my jugs, It was main jetted to 190 and slow jetted to 45. My Question is would the needle jet barrel use the bigger needle I took out of it or is the barrel the same as my old carburetor and accept my old stock needle. A chart I had gave me the specifics for which needle to use for my year and my carb but being a newer type carb has me a bit confused here on which needle to use. Hence "sometimes" a Pop though the air cleaner when stopped and throttling. This could be to my float level being a bit low as well as it flooded out the time before last on a short run. This carb has no over flow on the float bowl either and was bubbling out the carb into the engine then died.
 
#9 ·
A pop or spit back out of the carb throat usually indicates an intake leak at the manifold to the head connection, intake seals leaking. Squirt some WD-40 around the seal area with the engine at idle, if the idle changes there's a leak.
 
#10 ·
I got a replacement manifold from Dave63 and made sure the intake is not leaking. I just need to know if the needle jet above the emulsion tube is the same for older years as it is for the newer year 40mm Keihin carburetor or are there different sizes installed for different size engines. If the needle jet is the same then it is not the issue, if not then I need to get another needle jet for my year and engine size for the proper needle. (Just started it up a bit ago and did it twice when Gunning from idle) The engine lowers in RPM After the pop when letting off when this happens but doesn't do it all the time. Strange to me. The air mixture screw is responding perfectly to adjustments I readjusted the throttle cables to give a bit more slack with no change. Looking through Ronnies Parts page I see most bikes use the same Needle jet except one in 2006 So I doubt that's my issue 2006 27100-86A 1993 27100 88 I,ll check the float level when My 175 main jet shows maybe tomorrow and do a better inspection of the enricher and needle then. Thanks SCHMIDTY
 
#11 ·
The needle jet doesn't have a size and are never included in jet kits that I'm aware of. I didn't check Ronnies to see if they even have a H-D p/n.
I've never had to replace a CV needle jet yet ! Emulsion tubes and needles ... yes, but not the needle jet.
The emulsion tube is different between a Sportster and a big twin ... just saying.
 
#12 ·
:thanksOK Then I am using The Emulsion tube that came with the carb from the V Twin I bought. I do have my original Emulsion tube from my original 93 carb and will have a look at that issue. I did add some info to the last post I made. Thanks for the info on the tube.
 
#13 ·
One last thing though. When I got my S&S jet kit it came with one emulsion tube and main jets from 170 to 205 It had a chart for jets & needles for different models and different years from 883 up through Vtwin. so that kinda makes me think the numbers are just different but I,ll look anyway.
 
#14 ·
If I were you I would look at the part numbers for your stock carb at Ronnies and go with them, but with at least a #45 or $48 pilot jet. The stock #42 is to lean !
The CV you have now is off an EVO big twin right ?
 
#15 ·
Yes Off an Evo Big Twin I jetted it to a 48 slow jet and a 170 main but I am waiting on a 175 main. According to the sticky I made Stock sportster jetting 1992 - 1994 main stock says 170 42 slow jet. I have the Hi flow drags and the K&N filter so 175 should be right. I just got back from a ride and still happening occasionally. I,ll tear it apart when the New Main jet shows & have a good look at the needle and check the emulsion tube. Double check the new exhaust pipes with new flanges are tight as well when it cools down some. Thing is it didn,t do this until the Needle jet fell out a week ago.
 
#16 ·
Just an update. New 175 main showed I took the carb off and redid everything. I did notice the emulsion tube had the same amount of holes but different locations so I went to the original one I had after cleaning it up. I cleaned the choke nipple and replaced the nylon nut with a stainless nut which fixed my choke cable slip. I added the 175 main jet which now has the right pick up I have been wanting. Cleaned the 48 slow jet and reinstalled it. Looked over the needle and no wear on it. put it all back on with a new seal gasket to manifold and then went for a long ride. (Damn Spring Break Traffic sucks but went another route with more open road but yet still had some stops). Damn if it didn't pop twice during the hole run. It was running so good I thought I got it. Now I'm thinking I better change the OLD fuel line and start using a different gas station (SHELL) Whatever it is seems to only happen occasionally (Not all the time) The point of the occurrence is when the Vaccum just lifts the piston. All vac lines are good. Float level checked as well. Lastly It seems when I take off I hear a faint timing sound It may be possible my old cam sensor might be the cause. I do have a replacement OEM sensor but would hate to go through that if I don't have to. Being my Oil tank seemed a bit high I took a turkey baster and emptied about 3/4 of a small bud can out and may help with the pressure.
 
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