Does anyone know why all of the Kirby vacuum cleaners produced before the Heritage have a sudden decrease in load when you lower the nozzle enough to the carpet being cleaned -- that is, the sound of the motor rises in pitch when you lower the nozzle? I know by comparison the Royal's motor sound decreases in pitch whenever you properly adjust the nozzle.

Could it be due to the extra weight of the metal fan? Or the way the nozzle was designed?

~Ben

Ben,

I am not sure what is going on with your Kirby's but the sound of the motor in my D50 Does Decrease in pitch when the nozzle is lowered to proper cleaning height just as you would expect. My D50 Does have a new Amodel polycarbonate fan in it but I don't think that is what's causing the difference in pitch.

Now Kenkart is only partially correct when it comes to Kirby vs Royal airflow and here's why:

It all boils down to Nozzle and Rug Plate design.

He is correct in that all Royals do not seal to the carpet because if you look at a Royal rug plate you will see a notch formed into it on each side which allows airflow to enter on each side when the nozzle is lowered down to the carpet preventing a complete seal from taking place.

Now on the older Kirby's. like my D50, you will not find any notches in the rug plate therefore an older Kirby will form a seal to the carpet when lowered into cleaning position.

 I am not sure when Kirby decided to add these notches or indentations to the rug plate but my Heritage II Legend and both my G3 and Sentria have the notches in their rug plates so that means the newer Kirby's, just like Royals, do not completely seal to the carpet when the nozzle is lowered to the correct cleaning position. 

Now after all that, I don't think nozzle and rug plate design are causing your problem either because my D50 acts just like my Royal 8300 and all my other Kirby's. You might want to check your brushroll for wear and make sure it is adjusted for proper bristle length past the rug plate. 

I find that my older Kirbys get a lower pitch one lowered to the correct height.  This is what we would expect, as airflow and RPMs would dip slightly from the triple-cushioned vibration.  That's really weird that your Kirbys seem to kick into a higher gear as soon as they seal to the carpet???

Ben.

Thanks for posting Tom's videos as I had not seen them.

Another thought I just had re: your pitch issue is what type of carpet do you have? If it is short or low pile, that might make a better seal causing an increased vacuum inside the fancase which would allow for higher motor RPM. Just FYI, I have a medium pile plush carpet in my home.

~Stan

Harley,

It is those edge cleaning ports on the Royals that I was trying to describe that are what's preventing a complete or total seal. Even though the Adjust-O-Rite button sucks in, there is still air entering from those side ports that prevent a complete seal.

The older Kirby's do not have the edge cleaning ports,. so they would form a tighter seal on low pile glued down carpet causing higher motor RPM on D50's and D80's and such.

If Ben has thick plush carpet, then I am lost as to what is causing the symptoms he described.

I'm not sure I understand your last post.  The Tradition did come after the Classic III (in fact, it was the model after the Classic III).  So, when did the suction release vent disappear, with the Heritage?