Hey long time browser first time posting. Ive been looking into it and i couldn't find anything. I have a 1991 vert and i was just putting on the dual pulleys and while i was tightening the old fan pulley it was spinning the whole pulley assembly and Im a little confused on this matter so be patient pls. Im not really sure what the technical term for that air sound when turning the motor so let me know thanks!

 

That air sound is compression, you should be able to hear that when turning the engine over. And depending on how tight you have the belt,it is possible for the engine to spin while tightening the pulley.

 

Ok it just seemed really easy compared to my friends thanks

 

It's normal to easily turn the engine over by hand. They don't make much compression at such low speeds.

That's why you need a good starter/battery/cables.

 

Thanks a bunch love how helpful the rotary family is