I have a '99 Heritage Springer with a bone stock EVO. I will be putting Fishtail straight pipes on it and eventually an Andrews EV-27 cam when I can get the time and money. So for now it is just the pipes and air breather.

I picked up the Screaming Eagle air breather kit today and the guys at the local HD service dept. gave me a list of things to do to the carb after I explained what I was doing to the bike. I guess they have done this so many times they know what they are doing on the tuning side of things. As soon as I told the service guy he went to his file cabinet and handed me a 2-page instruction sheet with diagrams. After reading it through I noticed it is similar to what is posted on the nightrider site in regards to the CV. There are a couple of differences...one is the size of the hole to be drilled and the other is the HD list suggests clipping 3 coils off the spring. Has anyone done this or should I just leave it alone?

This is what the list suggested:

1. Cut 3 coils off of Diaphragm Spring

2. Drill air passage with #29 bit

3. Install PN 6048W washer (1/8x1/4x1/32) under needle

4. Replace slow jet with #45 (different sizes were listed for newer models) #48 for 2000 and up.

5. Remove mixture plug, turn screw in til it bottoms and then turn back out 3 turns. Adjust as needed.

 

Whatever you do...don't do 1 and 2....leave the spring and slide alone, I would go up 15% on the main jet as well and once the cam is in go to a 190 main, mine has a 200.

 

what spanner said ^^^

my CV likes a 200 as well

 

220 here... But I'm special...lol

 

DO NOT DRILL THE SLIDE OR CUT THE STOCK SPRING for a stage 1 or 2 engine on the street. This will give you a dip around 2,500 RPM (right where you cruise) and can give you a sawtooth torque and HP curve from the slide oscillating up and down. We like the '88 sporty needle rather than the shims (it has a lot to do with the taper of the needle and when it adds fuel) as it seems to work better in most of the above installations. Hope this helps.
John

 

Thanks guys. The reason for asking this was specifically to see if anyone had ever cut the spring since this is the first time I had ever heard of cutting it for the EVO. Also there was a question as to drilling out the hole. Nightrider states to drill it out to 1/8 inch and these instructions state a #29. Having previously owned Shovel heads and TC's I don't ever remember drilling the hole out to a larger size. I wanted to make sure I didn't ruin a perfectly good carb before proceeding.

By the way, this Heritage Springer was found with only 4807 miles on the odometer. It looks like new other than a couple of tiny chips in the paint. I have been looking for a good low mileage Springer for several years to replace one I sold (yeah, still kicking my own a$$).

miacycles, I had read about the sporty needle but the dealer was out of stock on them so I am going to try the shim for now until I can find a needle. The nearest HD dealer is 100 miles from me so I don't just take a short trip for parts. may as well plan on a day wasted just to get what I need.

 

Hi I am having similar problems with my 1996 Evo. We bought it online so god only knows what the cam is. I know it is atleast one size over stock. Also when the bike is Idling it cuts the front cylinder and chugs on the rear until it is warm and then it runs great. I put a dyno jet kit in the CV carb and made the idle mixture screw usable by removing the stock aluminum plug. Three turns out and it still runs on one cyclinder. it has a 45 Pilot jet and a 185 Main. Any suggestions as to why it would be doing this? I'm stumped once again. Also if it makes diagnosis easier it is running dual fish tails with baffles but there is no cross over. Could this be a back pressure issue?

 

Did you check your intakes?

I really doubt it is a back pressure issue.

 

I did my 92 fatboy along the lines of the nightrider sight. I did not cut the spring since I've heard many horror stories on that. I did drill the slide except I used a 7/64 bit rather than a 1/8 bit. I also cleaned the slide up with 2000 grit paper just to debur. As for jets mine is stock motor with v\h longshots with 45 pilot, 180 main and 2.5 turns out on the mixture screw. I used the 88 Sportster needle also. I have a hypercharger for a\c.

 

First - if it's not firing on the front cylinder, I'd check the intake seals and coil leads. I don't see how the exhaust characteristics could contribute to your symptoms. One other thought: Do you have adjustable pushrods? If so - one the front pushrods could be adjusted a bit tight, keeping a valve slightly opened causing a loss of pressure 'til the cylinders expand at operating temperature.

Secondly, the DynoJet greatly over-richens your mixture. I'd strongly suggest getting the stock slide, emulsion tube, a 45 pilot and 190 main jet for your carb.