Rejetting issues

New to forum. Any help would be greatly appreciated. I've a 1997 883 Sportster just put on a Big Sucker and have been running a Thunderheader and Screamin Eagle 10mm plug wires an Screamin Eagle spark plugs, other than that stock. I've trying to get the rejettin right with little success. I have a 45 slow jet and 175 main (stock was 42 slow and 175 main) and installed a new jet needle from CV Performance. My best result was with a 48 slow and 175 main 2 1/2 turns out. Farts out of the Carb a little on cruise 4th gear 50 mph. Should I put the 48 slow and run 180 main? I'm at sea level. Thanks!!

Thanks for the advice. Will see how it goes today. Let you know. Thanks

I took it out for a spin. Noticed bottom of air cleaner soak in gas. Checked float level, way outa spec. Set float level to .433. Road tested, the bottom of air filter still getting soaked with fuel. 48 slow 175 main. I don't know about shimming needle, would the that would richen the mix. Maybe decreasing the float level more, down to min spec of .413?

Do you have a factory service manual?? If not, get one, I am not sure what the spec is for float height off hand.

Yep stuck float! To be safe got a new float and set it with in spec. Stuck a 45 slow and 175 main and the magic Early Sportster 1200 Needle 27094-88 in it. Took for a spin no issues. You guys are a great help hope to return the favor.

i took that advice right away when I joined this site. I have used it on acouple of different occasions. They dpo save time and some money....

Got the jetting right. I still have fuel collecting at bottom of air cleaner. Pulled the air cleaner of and started, cracked the throttle, found fuel spraying back out of carb throat. Found a article about fuel standoff on a another forum.

"FUEL STAND OFF''....this is a characteristic of a internal combustion engine with a carb on it. It has nothing to do with your jetting or acceleration pump intake leaks or timing......it's a pulse wave that happens when a column of air(intake) traveling at 650 feet per second into a cylinder THEN the valve closes on this column of air. The column of air with a charge of fuel in it just doesn't stop, (who was it that said for every action there is a reaction?) any way when the valve closes the charged column of air traveling at a speed of 650 fts bounces off that valve and makes it's way to the other head where it bounces off that closed valve and the column makes it's way out through the carb....now here is where this gets interesting...the carb isn't too smart, It doesn't realize which way the air is traveling so as it goes over the venture it picks up more fuel in the column of air that already had a charge of fuel in it....when the column of charged air hits the atmosphere it's like hitting a brick wall so the air is reflected back into the engine as a little weaker pulse wave but since the fuel is much heavier than air the fuel continues out into the atmosphere soaking your air filter and the whole right side of the bike depending on how long you have the bike under a load at high throttle positions.
To witness this you can take off your air filter and do a few runs on the dyno and watch this STAND OFF happen before your eyes....a plumb of fuel will hover out side the mouth of the carb up to 8'' away depending on the displacement of the engine, cam overlap, and exhaust system used.
Now when you take the time to set up ''Intake Track Tuning'' this waisted gas can actually be pulled back into the engine and used instead of washing your air filter. Intake Track Tuning is using the pulse waves of the intake to assist in cylinder fill by timing the wave to hit the intake valve as it is starting to open.....these are the things you do on motors that need the the EDGE to be a winner.

Hope this helped you to understand whats going on with your bike, you don't see or smell this gas on a bike with a stock air filter because it's all tightly sealed, nor will you see STAND OFF in a EFI bike because there is no fuel to pick up on the way out.
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Sorry for the long post, putting the stock air cleaner with a K & N back on the bike. Not running with a maxi pad hangin off my Big Sucker.

Now here is the million dollar question. Did this problem start as soon as you changed pipes and air cleaner or did you always have it?? I like the article as it was interesting but it really didn't say how to fix it.

You said that you got the jetting right. According to what? Did you change it and it is better?

I cut some of the article from the post. From what I read, a longer intake runner or velocity stack would take care of the issue. The screamin eagle air cleaner that I had on (and back on again) was and is collecting the unspent fuel. From I been reading those who are running a Big Sucker style set up with a carb motor have these issues. Holding onto the Big Sucker to use when I throw a 1250 kit at it and see what happens. I got the jetting right bike running good, plugs look good. Final setup 48 slow 180 main, SE A/C, Thunderheader, stock coil, SE 10mm wires and SE plugs.


Why Is There Fuel Coming Out My Air Filter? - Harley Davidson Community

Probably why the guys running Big Sucker and SE Breathers notice better throttle response and mileage running a V-ductor on them...