Sportster Carb & Intake Question

SwampFox - 5/31/2010 4:03 PM

Our 2002 883R in restricted stock form performs quite well as a sidecar tug and averages over 40mpg, but occasionally we need it to breath a little more air, such as when pushing into a headwind. I read that the customary routine on carb'ed Sportster's is to change the breather, jets and exhaust.

However, as I do not want louder pipes on the rig, my question is: Is there sufficient gain in airflow/horsepower with a less restricted intake to make it worth the modification, without changing the exhaust? For instance, I'm considering the HD Screamin' Eagle breather with a #165 main jet, keeping the stock 2-into-1 exhaust. Thanks for your advice and experience.

By the way, the Sportster has thus far been rock-solid reliable, even if it is "old-tech" and cold-natured. But I do need to pull the breather to address the oil blow-by issue.

You could check to see what jets you have presently. There is the mid jet and the main jet. There is also the adjustable idle jet that is originally under a metal cap. To access that one, it's necessary to remove that plug. When changing jets it's almost a requirement to adjust the idle jet slightly.

I don't know what sizes you have now but you could change the air cleaner and get some slight gain. If you do that, you should also do a spark plug check. You should do a high speed run for a mile or so and then shut the engine off without idling. Then remove the plugs and look at them for color. If they are bone white, a bit more jetting could be in order. I look for a slight tanning of the end and that's good enough for me.

You could probably go up a size on the mid jet since 80% of the throttle is using that jet and the idle jet. It not too often that you will get to full open. It also pays to leave the carburetor diaphragm stock. Sometimes people think it wise to cut the return spring down and drill out the air equalization hole in the diaphragm to get faster opening. This is a waste of time and money. The CV Carburetor is a well-designed instrument that usually only needs a bit of adjustment of jetting. Cutting and drilling will usully cause more difficult starting with no tangible benefit.

The Sportster already has a good needle so you can leave that alone, too. Remember, most anything you do is going to chip away at that 40 mpg fuel rating.

I agree with leaving quiet mufflers on. The passenger will thank you since the right muffler is right near the passenger's ear.

Good luck.

While I can't answer your questions per say I am pleased with my Super Sport (S&S) carb on my bike and I have it bored out to a 1200. I did put the stock pipes back on and the only jet that needed to be changed was the idle (from drag pipes). I don't know much about stock carbs on these bikes as all of ours in the family have S&S carbs. I was getting 40 still before the hack. Haven't taken my mine out of town yet with a new born I haven't had the time to and only my pup will go with me.

OK, I'm thinking I will try the HD Screamin' Eagle air/cleaner breather and work on the proper jetting. Maybe I'm slipping because it's hot down here in Louisiana, but my search is not locating the previous posts re: recommended sources for stock HD parts. Please advise if you know of a good source for the parts.

SwampFox - 6/5/2010 2:03 PM

OK, I'm thinking I will try the HD Screamin' Eagle air/cleaner breather and work on the proper jetting. Maybe I'm slipping because it's hot down here in Louisiana, but my search is not locating the previous posts re: recommended sources for stock HD parts. Please advise if you know of a good source for the parts.

Zanotti's, Hale HD, Chicago HD are all quite good and offer discounts. The exact URL's are on Google.

Thanks 109. I now recall those names mentioned here before. I'll go shopping now.

SwampFox - 6/5/2010 8:32 PM

Thanks 109. I now recall those names mentioned here before. I'll go shopping now.

Yeah, we used to have a dealer close to me and I could get things like that from them. They closed the shop and it's an 80 mile round trip to the other one so I just use the internet.

Good hunting.

Well, we've installed the Sceamin' Eagle breather kit, and on the 4th adjustment of the 4th combination of jets, the Sportster is back to running good. The magic configuration for this bike w/stock pipes as +1 on the main jet (to 165) while retaining the stock 42 slow jet, but opening up the mixture adjustment about 1-5/8 turns.

The bike takes the throttle better, doesn't fade quite as much on the hills (and hopefully a headwind), has maybe a couple or 3 extra horsepower at the expense of about 4 miles-per-gallon.

Oh yeah, NO oil blow-by on the bike or me after 150 miles today. 🙂

SwampFox - 7/3/2010 7:58 PM

Well, we've installed the Sceamin' Eagle breather kit, and on the 4th adjustment of the 4th combination of jets, the Sportster is back to running good. The magic configuration for this bike w/stock pipes as +1 on the main jet (to 165) while retaining the stock 42 slow jet, but opening up the mixture adjustment about 1-5/8 turns.

The bike takes the throttle better, doesn't fade quite as much on the hills (and hopefully a headwind), has maybe a couple or 3 extra horsepower at the expense of about 4 miles-per-gallon.

Oh yeah, NO oil blow-by on the bike or me after 150 miles today. 🙂

That sounds good. Apparently it's all dialed in.

Happy Trails. 🙂