crackling and popping

[pfo186]

hey all,
my right side cylinder is crackling and popping when i let off the gas. i asked about this in another thread and everyone said it sounds like it's too lean. i have no air leaks and my air mixture screws are 3.5 turns out and it's still doing it on the one side. i think the air mixture screws were tightened down too far on adjustment (to zero it out and count 3.5 turns back) and the end the screw is more blunt than it originally was. i was hoping to get some suggestions on a good site to get a new air mixture screw (77 xs400).
also a new rear sprocket? i wanted to get one with less teeth so the bike is at a lower rpm at cruising speeds.

i appreciate the help, look forward to the comments.

p.s. could this also be from my valves no being at the correct clearance?

 

[drewpy]

yamaha still do the mix screws not expensive. the problem you will have is to get the old tip out of the carb. I pushed mine through with a really thin ground down nail (on both carbs)

wemoto uk do different size sprockets

 

[pfo186]

will the air mixture screws being blunt cause the bike to run lean? because the bike runs really good minus the crackling and popping when i let off the gas. either way i'm getting new air mixture screws, but i was just curious and trying to limit other factors that could be causing the crackling and popping.

 

[drewpy]

sometimes it can be just crappy fuel.

mine does it on really hot days, but its rare (not many really hot days in UK)

 

[HoughMade]

You're a snap and some milk away from a tasty breakfast.

 

[drewpy]

You're a snap and some milk away from a tasty breakfast.

wa wa waaaaaaaaaaaaa

 

[leedutcher]

^ hey that was kinda funny...lol

 

[pfo186]

What type of gas does everyone use in there bikes? I use the standard stuff at the pump (87 octane) and put a little bit of fuel treatment in the gas to get rid of the 10% ethanol. should i be using the 93 octane? could this be part of my problem? I have to use 93 octane on my motocross bike, but i figured it didn't matter on this bike since it is so old.

thanks again.