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*Twin Cam CV Carb Rejet Suggestions

Let us know how it works out with the #46 jet and the other changes.

Well, now that my suspension (AKA "vacation") is officially over, I can finally get back to you with the results. Changed the #48 jet to the #46. Added the two #4 washers to the needle, and installed the EZ just mixture screw. I left the 190 main jet in cause if I changed everything at once, I wouldn't know what was making it better or worse. Now my bike starts immediately, doesn't take as long to warm up (it used to take at least 5 minutes before it would idle on its own), and I rode it about 100 miles and not one pop thru the carb. Seemed to run a little cooler too, but once we hit the Texas heat in a month or two, I'm sure that will change. Too lean makes it run hotter, right??? I got it up to about 60 mph in 3rd gear and chopped back the throttle some, and it seemed fine, so the jetting must be right on. Think I'll leave the 190 main jet in. I still don't see much difference, if any, when turning the idle mixture screw, unless I go almost all the way in, and then it almost dies. But from one whole turn out to 3 turns out, I hear no difference in the motor. So I left it at 2 1/2 turns out. Something else I realized after loosening the throttle cables all the way to remove the carb, was that whoever worked on it last (the HD dealer from before I bought it), never adjusted them properly. The cables were preventing the carb from opening more than 3/4. I adjusted them so now I can open the carb all the way if I need to, which I don't do that often, but it's nice to know I can.
Thanks for your advice Mr. Data. :bigsmiley12:

And now for another question. Don't know if I should post it here or on another topic, but since I'm here already, I'll post it here. I see you like the Spectro tranny fluid. I didn't read the posts before I changed mine two weeks ago and put in Amsoil 75W-90 synthetic gear oil. Should I change it out to the Spectro 75W-140, or is the Amsoil ok for now? It's so clear and clean that it's hard to even see on the dipstick. Which brings me to another point. I read on other posts that some dipsticks were being cut in half by the clutch cable, so I bought another one at the dealer so I could cut one off and just use it as a plug, and keep the stock one for checking fluid level. Talking to the guy at the HD store, he said (and it makes sense) that it only gets cut in half if you put the dipstick on the wrong side of the clutch cable. Looking into the tranny filler hole, the cable is not right in the middle, but offset to one side. The dipstick could be inserted into the smaller side if not careful, allowing the cable to eventually wear thru it.
And speaking of dipsticks, somewhere else on this forum I read that one guy was getting different oil level readings with the stock dipstick and the LCD thermometer dipstick. In case no one set him straight yet, (I can't seem to find where those posts were anymore), the stock dipstick is to be used with the bike in the upright position and the thermometer dipstick is used to check the level when it's on the jiffy stand. This could account for why he's getting different readings. Bet he was checking them both in the upright position. Not sure why they would make the dipsticks like that, but it is what it is. Feel free to move this part of this post to the proper place if need be, and I'll try to refrain from getting put on "un-paid vacations" again.
Muchos gracias amigo :cheers
 
Hi Mr. Data, I just purchased a 2003 Dyna LowRider (carb) and it currently has a Screaming Eagle Air Filter (Harley) and Screaming Eagle Slipons. It runs great as is and I found out that it has a #48 slow jet and a 190 main. There is also an ez-mixture screw installed. I am planning on installing a K&N air filter and a set of Vance and Hines Big Shots next week. Do you think this change will have much effect on the current jetting? I do not know if anything was done to raise the main jet needle. I saw a description of the carb job that was done last year (on the bill the original owner kept) and it said that the Bladder Spring and Needle were replaced. What is a Bladder Spring?

Thanks,

Bob
 
What you are referring to is the vacuum diaphragm on the slide and the 48 is a tad rich. It would probably be better with a 46 low jet and check to see if the needle on the slide has any shims under it to raise it.
 
The amsoil is a great oil... However i don't like using synthetic in my primary because there are friction modifiers in it which can cause your wet clutch to slip....

I just re-read your post and you were talking about the tranny, not the primary... my bad, the amsoil should be great.
 
Hi Mr. Data,

As I posted earlier I have a twin cam with air and exhaust mods and found out that I have a 48 pilot and 190 main. I know you said that a 46 pilot would be better but I haven't got around to changing it yet. But I am a bit confused because after reading some of your replys to other posts, you have suggested that anyone that has to turn their air/fuel mixture screw out more tha 3 1/2 turns should probably use a bigger pilot jet. I checked mine and it is exactly out 3 turns...and this is using the 48 pilot. If I put a smaller pilot jet in wouldn't that mean that I would end up turning the mixture screw out more than 3 turns? Then I would need to go back to a 48. Do you have any idea why this is?

Thanks,

Bob
 
There are many variables. It would depend on how well adjusted the mixture is at 3 turns open meaning if you slowly closed the idle screw down when fully warmed up would the idle falter or slow down much going closed from 3 turns but before you reached 2- 2 1/2 turns. Hard to put this into words but try closing it down and see how much you can close it before the engine shows the results in speed or faultering. Also see if you can stall the engine by lightly seating the screw (closed). If you can't stall it, then put in the 46 jet.
 
Hi Mr. Data,

I turned the mixture screw in from its original 3 turns out and the bike began to stumble at around 3/4 to 7/8 of a turn inwards (or 2 1/8 to 2 1/4 turns outwards). Not much changed while turning the screw in the first 3/4 of a turn. I took a test ride with the screw set at 2 1/2 turns out and the bike still accelerated good but popped a bit when deaccelerating (which it never did at 3 turns out). I finally got the bike to stop popping after several adjustments and basically ended up with the final screw setting at 2 7/8 turns outwards (not much different from where I started). So all this was with the #48 pilot that is currently installed. (nothing has been done to the jet needle). Also, the plugs have looked pretty good. At this point do you still think I should change the pilot to a #46?

Thanks,

Bob
 
The 48 jet is a bit large for for all but modified motors. Your idle mixture jet seems to be about right but not for that large of a jet. Possibly try the 46 and see what results you get. More fuel form the bigger jet will maker the throttle response a bit sluggish.
 
Mr Data , i read all of the problems people have presented to you ,and your responses . I have an 05 nightrain 88b motor, SE2 slip ons and a spike breather. did the 2 washers & the #46 jet turned out aprox 3 turns . does not change at all between 2 -3 turns . but it will pop through the carb when i start to crack the throttle . not all ways just every now & then .any help would be GREATLY welcomed .thanks PA58
 
Mr Data , i read all of the problems people have presented to you ,and your responses . I have an 05 nightrain 88b motor, SE2 slip ons and a spike breather. did the 2 washers & the #46 jet turned out aprox 3 turns . does not change at all between 2 -3 turns . but it will pop through the carb when i start to crack the throttle . not all ways just every now & then .any help would be GREATLY welcomed .thanks PA58

That sounds like you are just a wee bit lean at that point and perhaps the next size up main jet will eliminate the pop you get at times

Brian
 
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