exhaust popping

[old_skool]

Just finished installing the rebuilt/cleaned carbs, and synced, cylinder 1&4 running a lot cooloer than 2&4...lean?? adjusting the carbs not making much difference, also, when warm, when starting-revs up to about 2500 then settles fairly quick to normal idle 1100-ish, pops through exhaust when letting off throtle after reving. has a slight exhaust leak where #2 header connects(needs new clamp) I guess, what possible causes for #2-3 running so hot and the popping and initial rev? stock jets, stock exhaust, pods.
79SF

[BA80]

You need to re-sync. What type of sync tool are you using.

[old_skool]

just a manometer, clear line with red tranny fluid half up the board on each side, adjusted 1&2 then 3&4, then left to right with the center adjustment

[BA80]

Sounds like you did it correctly. Check it again it may be off again. I really don't trust that setup anyway.

Try 1/4 out on the mixture screws on 2 &3 if that's ok.

[old_skool]

Never had any problem doing it that way, I noticed this bike has numerous exhaust leaks, will that contribute to the popping? Still not sure whats causing it to race at start then settle down, runs a little rough, maybe the exhaust is clogged, seems ok at the back, still have issuses with the mixture. And I need a couple clamps if any body has any, going to the middle two header pipes where they join just below the oil filter. Oh yeah, going to have to check compression too, PO washed the cylinders full of fuel also, when I got the bike, had a gallon of gas in there with the oil.

[natemoen]

Exhaust leaks will contribute to the popping. get those fixed and go from there, even if you just temporarily plug them with something to see how it changes things.

[trdriver71]

did you adjust the mixture screw after you synced it? if you you will need to adjust those then resync again.

[petejw]

leaky exhausts can cause the popping,
but shouldnt cause it to run hot,
did u check the float levels?
are they set to stock, lean fuel levels can
cause the engine to run hot.

[old_skool]

Yeah, I plan on re-syncing till the cows come home, floats good, all set factory, not just a little hotter, a lot, I used a laser thermometer at the the bend of the exhaust header, 212-240 degrees on the outside pipes 480-541 in the inner.
Adjusting the mixture wasn't making much difference unless drastic turns in or out.

[petejw]

u havent accidently broken any tips
of the mixture screws, that could also
cause u the problem, especially if turning
them doesnt make any difference.

[old_skool]

I'll double check, but they all looked good originally when I installed them.

[ViperRon]

You may want to check to ensure the Carb boots are tight as a vacume leak can create problems with carb adjustments making cylinders run lean and adjustments seem to change.

[old_skool]

I think it's a combination of 2 things, I did discover the carb boots aren't tight enough, and the exhaust was horrible, left side muffler was completely broke loose around the the pipe at the crossover junction, had holes in the bottom near the rear on the same side, center connecting headers loose below the oil filter area. Re-welded the muffler, patched the bottom holes, picking up some new clamps tomorrow, muffler had a little more surface rust that wouldn't clean up, so high temp black paint performed a temporary miracle...lol
Will take care of the clamps on the exhaust and carb boots tomorrow and go from there. Not sure how much all of that affected the 2 center cylinders running way hotter than the outer ones, after all is re-hooked up, will re-sync and attempt to adjust the mixture....fingers crossed. Hopefully I don't have to pull the carbs again, everything was spotless....except....forgot to pull the emulsion tubes.