13bbuggy

I have a sandrail with a 1990 Mazda 13b n/a motor and it has 2 1/2 inch exhaust into a Y pipe to a 2 1/2 in single flow master. The rear (#2 rotor) pipe is about 2 inches longer than the other one going into the Y pipe and one is about 16 inches long, the other is 14 or so. My question is would this have any effect or noises at higher rpm's as a result? Also, the leading spark plug on the rear rotor is blackish and the other 3 are clean, what could be causing this? I forgot to mention it's carbureted with a Dellorto 48 DHLA sidedraft. Thanks in advance for any help.

vw505

You could have an exhaust leak in it.

13bbuggy

would an exhaust leak cause the spark plug to be black?

vw505

have you cleaned the carb?

vw505

with the leak i was going with the back firing you were talking in anouther post.

13bbuggy

From what I understand the exhaust leak would only affect it during deceleration,and it's doing this on acceleration. I did clean the carb just the other day and replaced the fuel filter and it still does it. I shot a little video of it but every time I try to attach it to a post it gives me an error message.

vw505

how loud is your rail?