So after the rejet, things were great for a while. zthen the colder weather started and I got the deccel pops back. I read on here that that meant I was "lean" and oughta back out the slow jet. So before that I checked the Plugs. They have some carbon on them, but my 82 yammer was WAY worse. Lean is supposed to be white, right, not black?

Im so confused.

But anyway, back to turning the slow jet... DO you actually just open her back up and back the jet out? Is that what I should do in this situation?

061200c
shortshots staggered
rahlows airbox

 

No, inside the float bowl are the pilot/slow jet and the main/high jet. I think want you want to do is adjust the mixture screw out a bit. It's located behind the float bowl, not inside it. See here for details: https://www.hdforums.com/m_190110/tm.htm

 

Yes, adjust the mixture screw, maybe. You'll probably need to adjust the idle speed as well. I have to set my idle a bit faster in the cold weather, then back it off again in the Spring.

This has to do with the air density changes between cold air and hot air. Please don't ask me to get more techincal than that. Way too much science involved there for this bean counter to sort though.

 

I would go with Sporty Pig. Do you know what jets you have in there?

 

Yep, SportyPig is right about raising the idle speed for the colder weather but the decel popsissue will likely require a slightly richer idle mixture setting. It shouldn't require a jet change though if the motor was running OK in the warmer temps.

 

I knew when I put them in. I wanna say 180/45 but thats a guess right now. I went out and tapped the plug outta the idle mix and backed it out about 1/4 turn. We'll see where that gets me tomorrow when I have time for a ride. thanks!

 

I did the 180/ 45 jettingand at the same time turned the mix screw out 2 1/2 turns, it has run great warm or cold.

 

Mixture screw out 2-1/2 to 2-3/4 turns. FWIW, I had to go to a #48 pilot jet, but as cHarley says, "It shouldn't require a jet change though if the motor was running OK in the warmer temps."

 

The simple answer is that cold air is more dense then warm air. Because air is made of about 20% oxygen, the denser air has more oxygen in it that hot, thin air per the same volume. To be happy, the engine needs a "stoichmetric" air/fuel mix. That means the right balance of air to fuel. We can adjust the fuel, but not the air, so that is where we make the changes. Cold air has more oxygen for the same quantity of hot air, so we have to add more fuel when it is cold and back a little out when it is warm. With most cars ( i assume bikes are the same) the ideal rate is right around 14.7ish : 1. That is 14.7 parts air to one part fuel. Most people that tune for performance shoot for a richer mixture of about 12:1. As long as you are not drag racing for pinks, the difference in 14.7:1 and 12:1 won't matter while you're putting around town, just make sure that you are not excessively lean.

[end of Mr. Wizzard ranting]
[return to Bevis and Butthead mode]

 

OK I finally had a chance to ride today to see if my work had any effect. And BOY HOWDY did it ever. It's running like ****.
WTF did I do wrong? The only thing I can think of is that I should have turned the mix screw IN not OUT. I had to keep the choke open during the entire ride to work (37 degrees F, 5 miles) or it would sputter and almost die.

So thats it right? When carb tuning after a rejet, pipes and AC, the carb mix screw should be adjusted IN not OUT?!?!?!?