Sliding the pipe into the coupler til it comes on the pipe isn't the best way.. this is called tromboning and it is hard to set the needle doing this in my experience.


The best way is to run it without the pipe and check the RPM. Then connect the pipe, run the engine, set the needle and check the RPM. Then cut 1/4" off the header. Hook the pipe back up, run the engine, set the needle, check the RPM.

Repeat as many times as needed until the RPM drop. You can run it there, or back it back out 1/4".

A properly set tuned pipe won't "go lean in the air" under normal use...if you are running some very high RPM it might need to be set a little richer. Also, after the engine is "on the pipe" the needle reacts differently. Pinching the fuel line and letting the engine hit the pipe works good. Make sure the engine is rich enough, pinch the fuel line and see how long it takes the engine to jump in RPM. Usually about a second is about right. If you just screw the needle in til you get an increase you will be too lean. On the other hand, if you just back the needle out, the engine will just keep running until you throttle back....then it is way to rich to get back on the pipe. The pipe will take over the engine's needle. It takes some time to figure all this out.

I have pipes on a lot of engines, and I've set them all on the ground. Setting the pipe isn't the tricky part..setting the needle is.