Sounds like rod knock

[nc1500]

Hello everyone;

This may be normal but I still have to ask for piece of mind.

At highway speed (55-60, 16-1800 rpm) I occasionally hear what sound like a rod knock in a gas engine, though there is no other indication of a problem. The temps are normal, good and smooth power delivery, good oil pressure, no other strange noises. One mod I did was the HPX tube but I haven't heard of it causing this issue. In fact, is it an issue or just an annoyance? Thanks for the feedback.

[XTrider]

bad injector would make a noise like a rod knock on gas engines. once it gets bad enough it sounds like metal on metal hitting like your valves are hittinh pistons.