Still adjusting jets - Now with charts and stuff!!

[bombsquad83]

Not beyond the realm of possibilities.... Could anything else cause blowback? Timing? Low compression? I want all possibilities so I can take care of it and use up some treadlife

This hit and miss nonsense has to end

Timing is another possibilty that I thought about later after posting the first time.  No harm in testing compression and checking the valve clearances and timing.

[Nakedguy]

Doing all of this with a little help on Saturday

[Nakedguy]

Here's what I've got so far.  Timing is good, spark is good, compression is good, valves are good and plugs are good.

Carb boots had a leak, not on the engine side but on the carb side.(biggest issue and not that big of a leak.)

After fixing the leak

Started with the mains, 150, middle clip or stock needle, 2.5 turns. Way too rich.
Went to the 145s at 1 washer or clip 4, 2.5 turns, still rich.
Went to clip 1, or the same distance as 2 washers above stock on the needle, 3 turns.
Bog is gone! feels flat-ish but decent

I won't have any more time to mess with her until Friday, but really getting close.  Having the factory pro kit adjustable needles is really making the difference in tuning.

[Soloratov]

I'm with you. Here is what I have now. It just seems so wrong....

I went and sealed up the joint between the muffler and pipe. Then removed the restricting plate from the Sportster muffler. I basically have a 1 1/4" straight muffler. It's an open pipe with SOME baffling. So I work under the assumption is would be the 40/150/1 washer setup. Assumption wrong.

Currently:

40/147.5/no washer. Seems FAR better than any other test so far.

Could this possibly go to a 145 main!? I'm going to run out to the bike shop and pick some up to try...just seems so off...

[bombsquad83]

What is the diameter of the sportster pipe vs some of the other aftermarket open exhausts?  A smaller diameter can actually provide more speed to the exhaust that does a better job of scavenging air from the cylinders for better flow.  If the sportster exhaust has a bigger diameter, it could be slowing things down and not performing as well as a smaller diameter pipe might.  There is obviously an ideal exhaust diameter that is not too small and not too big.

[Soloratov]

The inner diameter of the muffler is 1 1/4 inches. There is technically some baffling going on since I did not remove them, I just gave it a straight shot out.

After some more tests....

40/147.5/NO washer and 4 turns on the air screw! Even better performance now. So, I will stop out and pick up some 145's and then reset the mix screws to about 2 turns and start there.

[Nakedguy]