Too loud motor when vacuum operating - Black & Decker AV1200 DustBuster Handheld Vacuum

It sounds like the small silver piece that fell out of your BISSELL Powerforce Helix may be the motor brush. The motor brush is a small, spring-loaded carbon block that makes contact with the motor to conduct electricity. If the motor brush falls out or is not installed correctly, it can cause the motor to make a loud, high-pitched noise.
To fix the problem, you should locate the motor brush and try to reinstall it. The motor brush is typically located near the motor on one or both sides of the vacuum. You may need to consult the user manual or contact BISSELL customer service for specific instructions on how to access and install the motor brush.
If the motor brush is damaged or missing, you may need to purchase a replacement motor brush from BISSELL or a vacuum repair shop. Once you have replaced the motor brush, the high-pitched noise should go away and the vacuum should operate normally.

Loud vacuum is usually a broken fan which requires pulling motor.

Hey Mike! Excessive noise can be contributed to dirty filters or clogs. Here's a quick link to troubleshooting steps to assist you.

http://www.bissell.com/FAQDetail.aspx?id=1421&cid=ccsocial

they are all loud

It could be a worn belt. Sometimes worn belts can cause the vacuum to make funny noises. I have listed a link to the owners manual and a link to the belt you need.

Eureka SC4580 Owner's Guide

Eureka SC4580 Replacement Belts

http://geeksquad.fixya.com/ThreadView.aspx?prdid=0&thid=832949
Generic problem for all Vacuums
Motor is getting loud and
Posted by lchill on July 25, 2008
Motor is getting loud and smells like is burning
Hello,
I would advise you to ALWAYS to FIRST UNPLUG YOUR VACUUM before beginning any service procedure. I am not sure what type of vacuum, make or model # it is but if your motor is getting loud and it smells like it is burning, it could be 2 things, either you have a broken fan blade or your motor is on it’s last legs and is burning up and would be in need of a new fan and motor replacement. Please feel free t contact your local vacuum cleaner dealer in your area.
So if you need further assistance, please feel free to contact your local vacuum cleaner dealer in your area or in the yellow pages, or contact the factory phone number or website to further assist you with your questions.
Thanks, Don the Vac Man
Go Ahead. Use Us.

when you put the handle down it turns on the brush roll. you may need to clean the brush roll or replce it if the bearings are bad.also clutch and 2 belts are started when putting handle down for brush operation.

When the motor bearings start to go bad, they will make a loud noise. Some motors if a piece broke off of the fan, then it also will make a loud noise. You may have to replace the motor.

If its aloud grating noise the motors at fault the fan in the motor is catcthing its housibng

When they get real loud either the motor bearings or the motor fan are bad and you will have to replace the motor, part #2031100, would sell for about $45.