Popping on overrun

[twincamman]

buy a miata-no really --after 20 years of Webber carbs I have found if it pops on a humid Friday it wont on a dry Saturday---popping affects little except to bother one --and reveal a possible exhaust leak --enjoy the days it wont pop grit your teeth the day it does ---now LOUD bangs are another problem-also only set the mixture /idle screws after a brisk motor--they should not be more than 1 and 1/4 turns out or something is wrong -they will jump into tune when hot -- ed

[type26owner]

John,
Have you tried fattening up the idle mixture yet? I dimly recall now that the popping went away after I stopped the air from leaking down the threads of the those idle mixture screws on the DCOEs. Could be wrong though. I'd give that a 50/50 chance at best.

Did you happen to have cleaned the carbies recently? Perhaps with compressed air? If you did there is a chance some of those lead pellets are loose and leaking air into the idle circuit passages.

[triumphelan]

I needed a new rear box so when I ordered one from CN I ordered a set of exhaust manifold gaskets as well .I removed the exhaust system from the manifold,I could not fault it ,removed the "Y" section cleaned it all up ,fitted the new gaskets ,new clamps all round and the back box.I took it for a run on a long down hiil road and on overrun the popping has gone?
Thanks for all your help ,although I could`nt fault the exhaust system I think it was the cause of the poping