Mazzer super jolly - what are signs of motor/bearings on the way out?

[rindfest]

I went to check out an SJ for sale locally, from a defunct coffee shop.

With the grinder empty, when the motor was spinning down [ie with no power applied] it made a kind of a ffffvvvv mechanical noise/hum. I expected it to be fairly silent when spinning down

is this normal or the sign of motor/bearings on the way out?

also the doser handle did not return-- is this an easy fix?

thanks!

[cannonfodder]

The doser handle is probably a dislodged or broken return spring. The motor noise is more disconcerting. From what I have heard (I have a Mazzer Mini) those motors are pretty bullet proof. It could just be dirt (or old beans and grime) in the burr carrier. You can rebuild the motor if it is the bearing going bad. You would want to replace the burrs. Given the duty cycle, even if the bearings were starting to go, it may run years in a home before they actually need replaced. I guess it all depend on the asking price, is it worth the chance for a $600 grinder.

[HB]

You're probably right about the bearing, that sounds like one of the Tagex grinders that Lino et al bought. He replaced a bearing for a few bucks and was off to the races. But keep in mind that he's Mr. Handy Extraordinaire. From what he said, getting the motor in and out was a pain because it's pressed into the shell.

[cannonfodder]

Another reason I like my La Cimbali Jr grinder so much. 4 (or is it 6?) screws and the entire case comes off, 4 more and the motor drops out. Bearings are tricky, they may whine for years before it actually goes, or it may go after one day of use. I would imagine that they use sealed bearings not only for the NFS rating but to keep coffee dust out of the raceways. If they are not sealed, you could sneak some grease into raceway to prolong their life.

If the price was right, I would get it. But I have also built a car from the frame up, and replaced a few bearings.

[lino]

It is a pain to press the motor in and out. Sean Lennon suggested a much easier method. Heat it up.
Put the grinder in the oven at a lowish temp 250-300, and wait till you hear the clunk...

BUT... You don't need to get the coil out to change the bearing.

You'll still need to pull/press the lower bearing carrier, and possibly the upper bearing - either off the shaft or out of the housing, or both. A nice cheap puller set or two from Harbor Freight, or the like, works well as you can mix match and grind the tool to fit your needs.

The bearing was about $7 from Enco, if I remember right. The original bearings in the SJ were shielded, not sealed. I replaced them with sealed and it's slightly louder (than a working shielded one), and spins down faster. Seals add friction and noise. The SJ design does a reasonable job of protecting the bearing so it doesn't need seals.

ciao

lino