Question folks... what's the worst carb jetting setup you've ever seen on one of our bikes? Asking because I just spent the last 90 minutes pulling my carb off, re-jetting it, and putting it back together.

First off, bike is nearly stock, has a 6" uni-pod filter, Dyna muffler, and a Raptor petcock. Been running it for the last two weeks and it's okay, bu it seems to lean out above 3800 rpm or so. Figured she's running too much air now, and needed a rejet. Thought I had a stock carb, still had the brass plug in place when I started. A half turn out screw adjustment helped the backfire, but she still didn't run like she should.

First mistake, assuming no one had fugged with this carb.

Opened it up and saw the main jet had obviously been wrenched on. Pulled it, it was a #150... no big deal. Pulled the pilot jet... WTH? A 35? Am I reading this right? Went and got my big magnifying glass.... yup, still a 35 jet. turned the idle screw in and it had been out almost 4.5 turns.

But, the worst is yet to come. I pull the top off the carb, and pull the needle. No white spacer. In it's place there's a piece of black rubber hose that's about 5/32" long. No wonder she's leaning out!

Put everything back together with Lancer's jet kit, used the reference here for the K&N filter and HD muffler combo... settled on a 52.5 pilot, 152.5 main, two washers on the needle, and 2.5 turns on the screw.

Comparing the holes in the pilot jets, yeah, that 35 is only 2/3 the size of the 52.5... dang that thing is tiny!

Put her all back together and fired her up. She runs better, sounds better, can't wait to see how she drives now. My guess is a whole lot smoother.

So... what's the worst carb setup you've ever seen?

The idle fuel mixture screw should not be adjusted by turning it to 2.5 turns......it should be adjusted by running the engine and adjusting the screw until the engine runs the smoothest.  You can start at 2.5 turns - but then you need to adjust it.  Turn the engine idle speed down a little bit less than 1,000 rpm, then turn the screw in and out until you find the smoothest idle.  If you have to turn the screw out more than 2.5 turns the pilot jet is too small.  If you have to turn the screw in more than 1 turn from seated...the pilot jet is too big.  The ideal setting is 1.5 turns......there is no reason to turn the screw out more than 3 turns the adjusting screw no longer has any effect....as the tapered needle on the screw is no longer restricting the flow through the seat.

 https://www.youtube.com/watch?v=zm5mB3R8Ucw

Once you have the idle mixture screw set properly you can then turn the idle speed back up.  You don't want the idle speed up high when you adjust the screw - as the slide and needle jet may be flowing fuel and will make adjustment of the idle fuel mix impossible.

Yup,.. dat's right...
Less than 1 turn open,.. you are pretty much shutting off the idle mix to make up for too much pilot jet...


...or you may have a sticky throttle butterfly that won't close all the way down...

And there I was, confused, trying to understand how to turn a screw In from seated.

Well, just got back from a half-hour test ride... man what a difference!

She winds up a whole lot higher than before, just pulls and pulls and pulls... had her up to 75 in third gear, uphill to boot! She runs, oh my goodness does she run!

Power comes on steady, just a nice smooth push right up to the top of the rev range. But...

Down low is still an issue. Too rich. She bogs and stumbles off the line, get her moving and all becomes well. Still doing that even with the screw turned in to 3/4 of a turn. Going to let her cool off and I'll swap out that 52.5 pilot for the 50.

That one issue aside, she runs like a whole 'nother machine now! Thank you all for the help.

Justin, saw it, but my brain corrected it on the fly... yeah, it's kinda hard to "screw in" a screw that's been seated.

Swapped out the pilot jet last night, put the #50 in. Idle seems to be better, will know more when I ride her to work this morning. Let it idle last night to warm up, adjusted the screw, she seemed real happy at 1-1/4 turns. Again, time will tell.