Belt slipping...with a twist (not literally)

Hi Folks,
At the end of my last roast, I noticed a slipping belt sound. I’ve fixed this issue before, so no big deal. But when I took off the back cover, I saw fine metal shavings at the bottom of the chaff collector. They appear to have come from the rearmost surface of the pulley. As can be seen, there aren’t any clearance issues, and I don’t see any corresponding scuffing on any part in that area. Any ideas on what’s going on? Secondly, I followed the instructions for tightening the belt. Since my Bullet doesn’t have a motor spring, I loosened the motor bolts, pulled the bracket over, and retightened, but the motor slid back to where it seemed like it started. Against my better judgement, I followed the directions that said to stop when it feels like the screws can’t be tightened further. I would have had to get a hex wrench with more leverage to do more than that anyway. Is this normal? I think I vaguely remember this happening last time too, but it has been many years since then. It doesn’t make the belt slippage noise turning the drum by hand now, but it didn’t do that before the adjustment either.
Thanks for any insight.
Eric




Hi @chicken.vindalo,

Could you try gently pulling the Pulley and see if it’s loose? There’s also a possibility that the green beans get lodged in between the Drum and the Front Plate, causing the Drum to push the Pulley back to the Squirrel Cage. You can try loading 1kg of green beans to the Bullet when it’s cold and check if the issue comes back.

Best regards,
Kevin

Hi Kevin,
I checked the pulley and it’s not loose. I haven’t had a chance to test it with 1 kg of beans yet, but I’ll get to that soon.
Thanks for the response.

I just thought I would post a follow up to my original post as I just roasted for the first time since then. I had tried to tighten up the belt, but as I noted it didn’t seem like anything really changed so I wasn’t optimistic. Sure enough, as soon as I started up the Bullet, there was that same noise. I took the back cover off and restarted it, expecting to see the belt slipping. Much to my surprise, the belt was fine, and the noise was clearly coming from the rear (impeller) fan. The set screw had worked itself extremely loose and it was the fan that was slipping, not the belt. I would have expected that to sound more like metal scraping, but it sure didn’t.
As far as the scoring on the pulley, this is still a problem. You can see fresh metal shavings on the pulley. When I push the drum back, it puts the pulley in contact with the retractable metal flange that keeps the back cover on. Is the problem that the flange extends too close to the pulley or that the drum moves back to that extent? Kevin, could you elaborate on your advice to put 1 kg of beans in the drum when cold? Load them as I would for a roast, I assume, and then do what exactly?
Thanks. At least the most pressing problem is solved.

Hi @chicken.vindalo,

Based on your picture, the shavings might come from the Impeller. Could you try cleaning them off, roast, and check if the shavings are still showing up?

You can still try loading the beans into the cold Drum and check if the Drum is having issues. Here’s how:

  1. Start the Bullet and directly go to Roasting Mode on P0.
  2. Load 1 kg of green beans into the Drum.
  3. Check for noise or beans dropping out of the Door.
  4. Once done checking, go to Cooling Mode and drop the green beans into the Cooling Tray.

Best regards,
Kevin