Intruders-Alert

So, when I bought a big heavy touring bike, I wasn't expecting 50 MPG, but I wasn't expecting what I got either. 25 MPG is not cool.

OK, start with the carb. Immediately found an issue. Float was to low. OK, sorted that. While I had it apart, cleaned and jetted for the open air filter and SE slip on. Few tanks in, I'm still not happy. Only getting about 30 MPG.

Well, here's where I'm at and I suspect I may have stepped up the pilot just a little big and I think I needed a new MAP sensor, as I don't have a VOES. (Picked up a new one cheap anyway)

46 from a 45 pilot
A/F just over 1 turn out
Original 190 main
CVP Velocity emulsion tube
EZ Just
Extended idle thumb screw
Completely cleaned and rebuilt

I'll post my results once I install a new MAP and possibly change the pilot jet back.

I've always thought VOES=Carb
MAP= FI
Interesting. What year is your bike?

MattSunn wrote:I've always thought VOES=Carb
MAP= FI
Interesting. What year is your bike?

03. VOES went out the door when the Twinkie was introduced. They basically do the same thing. Luckily for me Harley, in their infinite wisdom, used a generic MAP that tons of other vehicles use and even the local auto parts stores have them for about an Andrew Jackson. But I'm cheap so I ordered one online for about $7. Since I have to pull the tank and change it I'm gonna throw the 45 back in there. It's gonna rain here all week, so maybe I can get it done before I leave for Chicago Friday.

The MAP is probably the issue. I don't think the idle jet will matter that much, not a lotta difference between 45 and 46 to cause that poor gas mileage. If it's not the MAP, it could be an exhaust or intake leak that's making the MAP compensate. Any shims under the needle? Not too familiar with the big twins, so just throwin' some stuff out there.

MattSunn wrote:The MAP is probably the issue. I don't think the idle jet will matter that much, not a lotta difference between 45 and 46 to cause that poor gas mileage. If it's not the MAP, it could be an exhaust or intake leak that's making the MAP compensate. Any shims under the needle? Not too familiar with the big twins, so just throwin' some stuff out there.

No shims, just using a Sportster needle. I may put the original needle back in a try a shim or two to correct it, but my mid range is smooth. I thought the MAP seal might be the cause, but the new one comes with a new seal and cost the same as a new seal. I already used the propane method to check for leaks and didn't get anything from where I can reach with it. I put a new seals and gaskets on the both sides of the carb when I reinstalled it. I'm just using process of elimination. Start cheap and easy first. Already changed plugs and wires too.

If you have the 1988 Sportster needle, I think it was NC65 or N65, something like that. It was used on a Keihin CV carb with no accel. pump. So now you have both, the needle and the accel. pump. If the MAP turns out not to be the problem with your mileage, this combo could be. Again, I don't know a lot about big twins, but with your AC and pipe setup, I'd go back to the following. Leave the 46, put the old needle back in with, maybe, one shim. Leave the stock 190 main and back out your mixture screw to 2.5 turns total. Most carbed Harleys are lean in the idle and mid range, the stock main should be fine unless you're WOT all the time with open pipes etc. Best of luck with finding the problem, these things can be a real PITA sometimes. [emoji106]

The needle fixed my midrange surge issue, but it could be causing me to run a bit rich while cruising. I adjusted the a/f screw in because even at 2 turns out, it was too rich. Which is making me think the pilot is too big. I think with a combo of the original needle with a shim and the original pilot, readjust the a/f mixture screw, I'll be right on. The MAP sensor couldn't hurt either, as I'm guessing the other was ruined by the excessive fuel.

Any luck with the carb tuning?

MattSunn wrote:Any luck with the carb tuning?

I've been in Chicago for the last 4 days. I got my MAP sensor the day before I left, but had to work. After some much needed yard work and unpacking today, I'll try and get to it tonight.

Just typing crap to subscribe......

!	Message from: 98VS1400
	Like what you usually type is different? Next time, go to the top of the page, and to the right of "Post Reply" is a wrench icon. Press it and hit "Subscribe". No crap required. [emoji106]

Put the new map sensor in. Gotta tell you, one thing I already miss about my Intruder is not having to drain the tank to remove it. There's a line that couples the tanks on the Harley that you can't just simply plug, you have to remove at least one side. This requires draining the tank. Lucky for me, there wasn't much in there. After I got the tank off, it was relativity easy. Unplug, one bolt, replace, reverse. Easy. It seems more smooth, but I'm no expert. I guess this tank will tell. If there's no improvement, I'll start with the pilot, then the needle. That way I can control variables.

Still working on my issue, haven't got to ride the Harley lately, been too damn hot. Nearing the end of the tank and it's better, right now looking at about 35 MPG. Found out the spark plugs came a but lose. Torqued them to the high side of the value this time. So far, holding strong. Still think I'm gonna have to bring that pilot back stock. Everything I've been reading has lead me to that conclusion.

I know this is Metric, but I have been playing with a crappy economy on my 1500 too.

I decided screw it, if it's gonna suck then I better have power and ordered stage 3 jets from Gman. I got the jets yesterday (along with instructions) and put them in last night. My needles were already shimmed and I had tried pulling the shims before without any real change in MPG. It felt like it was providing a little less power, so I put the shims back in.

Now I have bigger pilots and mains along with more air coming in. The instructions said to have the shims and spacer come in at 2.96mm (he gave inches I converted) and when I measure mine I was waaay over. I measured my spacer and it is 2.98mm on it's own. I pulled the shim and reassembled the bike.

It pulls better through all ranges of the throttle but now I am delivering less fuel on the needle jet than I was before I can't really get my head around that one, but there it is.

I have no clue yet what it is going to do to my MPG, as I have to go run some tanks through to find out but I imagine it should increase since the needle jet is the single largest contributor to fuel economy.

scootermcq wrote:I know this is Metric, but I have been playing with a crappy economy on my 1500 too.

I decided screw it, if it's gonna suck then I better have power and ordered stage 3 jets from Gman. I got the jets yesterday (along with instructions) and put them in last night. My needles were already shimmed and I had tried pulling the shims before without any real change in MPG. It felt like it was providing a little less power, so I put the shims back in.

Now I have bigger pilots and mains along with more air coming in. The instructions said to have the shims and spacer come in at 2.96mm (he gave inches I converted) and when I measure mine I was waaay over. I measured my spacer and it is 2.98mm on it's own. I pulled the shim and reassembled the bike.

It pulls better through all ranges of the throttle but now I am delivering less fuel on the needle jet than I was before I can't really get my head around that one, but there it is.

I have no clue yet what it is going to do to my MPG, as I have to go run some tanks through to find out but I imagine it should increase since the needle jet is the single largest contributor to fuel economy.

Not to piggyback my own thread, but there's only a couple people reading it anyhow.

I believe the crappy MPG is attributed to worn needle jets/emulsion tubes. The needles are too hard for the soft brass. So Larry (Half Crazy) developed some softer aluminum needles that wouldn't damage needle jets/emulsion tubes. I believe he passed them on to Gary (G Man) and Gary started selling them on his website.

So, if it doesn't solve your issue, and you haven't already, order new needles and needle jet/emulsion tubes from Gary.