I am kinda kicking myself in the *** for not checking into the Sportster needle last weekend, as I have read a lot on that subject. In hindsight I did overlook it, not thinking it was a big deal.

Long story short, when I had the carb apart and was inspecting everything (slide, diaphragm, jets, etc), I cross referenced the stamped needle number (N9EZ) to part # 28019-04 JET NEEDLE. (Remember, I got this carb used but rebuilt a couple years ago when I did the MM to carb conversion, but didn't think to dig into what bike it came off of). Looking this needle up on various posts/sites showed it may be a fairly lean taper. I'm 15 min from our local dealership, so ran out and I grabbed a 27406-00 (N8EA), which should be the stock needle for the 2000 FLH carbed versions. This didn't make much difference at all. I should have just ordered a Sportster/CVP needle and waited for it. Oh well, I'm learning a lot on these CV carbs.

Now I just need some warmer morning weather to enjoy my 35 mile ride to work (was still 36F this morning....so not commuting on the bike yet)

 

Common mistake is compensating for a lean needle with a rich main. I'd do the needle then revisit the main. The main is generally on the rich side from the factory. Pilot and needle are lean.

 

Finally got to do some commutes to work and a couple short rides. I must have had too much fun at some higher speeds, because the oil started to breath a little too much into the intake, and the AC started leaking. This has happened before, but it was remedied by replacing the original breather components and drilling the oil returns just slightly larger. So I'll keep an eye on if this leaking becomes a regular thing. I've thought about getting the external breather catchers that mate up with the stock AC from DKC Products.

Otherwise the bike ran pretty good, but the 4500 RPM stutter is still there. I thought the main jet change got rid of it, but didn't seem to. Also, commuting at highway speeds (65-70) is getting me about 28 MPG, hopefully I can improve on that with some more tinkering.

So I've tried to get a N65C needle, and wow they are hard to find. And the CVP website seems to be messed up. They aren't responding to emails, and I see a TON of bad reviews in the last few months. Not sure if the business has not been doing well (same as many others) in the last 8 months.

So I picked up some #4 brass washers and decided to shim the current needle with one washer to start with. I also put the main jet from 195 back to 190, and started the tuning back over. Went for a test ride last night on local roads (40-55 mph), and one thing I didn't mention was the occasional carb fart on throttle blip that was happening before. That didn't seem to happen, and the throttle response off idle seems to be better with the needle shim. I think this is going in the right direction.

That damn miss/sputter is still happening at around 4-4500RPM. I'm starting to wonder if I have an intake leak, that only is showing up at high RPM. The leak doesn't show up at idle when spraying around the airbox gasket and intake boot with starting fluid. But, I guess some more work to be done!

 

Have you had the carb apart? Are you sure you have the needle jet collar in correctly; very easy to get it upside down.

 

Yes, that was the first thing I checked after changing the jet the first time, as I've had it upside down before a couple years ago, when I first removed the MM EFI.....

When that happened though, it would start but not stay running at idle. And you are correct, it's very easy to mess that up.

One thing I plan to note this next time I ride, when I have the problem at high RPM, does throttle position make a difference. That's something I don't think I was trying: getting up to 4500 RPM gradually vs WOT up to 4500 RPM.

 

I do know that on the Evo's with CV carbs and cam upgrades, some guys were using the 190-195 main jets... But that's an 80" motor... Maybe you need a 200 or even a 205 main.. You are running an 88"er, right?

 

Yep. Try leaving the main out all together. I think it's a midrange/needle issue. You don't need a main to tune the needle.

 

Doesn't the needle USE the main jet?
Also, isn't there a slow (pilot) jet? That would control fueling off tip-in, as well as cruise, right? If it's running lean, going to a larger pilot jet would help. IMHO.

Thoughts?

 

Check out the attached diagram. Needle does not use the MJ; it uses the needle jet. Pilot jet does control transition from tip in to about 1/4 throttle but from 1/4 throttle to about 3/4 throttle, the needle and needle position are in control which is why the needle is so important. At 28mpg, I don't think the OP is running lean.

 

Nice, that's an excellent chart! I ended up adding a 2nd washer to the needle and re-adjusting the mixture, before we went on a 150 mile ride yesterday. Not sure if I really noticed a difference. The high RPM sputter still seems to be there, even if it's at a slow increase to the 4500 RPM, (not WOT).

I started wondering if I need to adjust the DTT timing curve. I have it at the recommended 5-7 for "mild modifications". Since I have some upper "rocker/valve" noise that I've always seemed to have, I wonder if I can't tell the difference between that noise, and some pinging that may be happening. My MPG on this trip was 30.5 (could just be because this trip high speed was around 60, where when I had 28 MPG, it was on the highway commute to work where I do get up to 70-75 once I get into Green Bay). But I don't want to mess with too many things at once. If I read the instructions correctly, I would lower the Advance slope by a click to see if it really is pinging that I hear? Or would I move both the initial AND the Advance by a click?