Drum Scraping and Stalling/Jamming at 300+ Degree Temps

Hi everyone,

I’m hoping to receive some community help on a physical issue with my Bullet R1 V2. When preheating the drum, it will start scraping the front of the unit at around 300 degrees Fahrenheit. If left long enough, the scraping gets so intense that the drum stalls completely, and an awful da-da-da-da sound happens. I believe it gets jammed at that point and is unusable.

I’ve attempted to adjust the pulley, tighten the belt, and added two shims to support the bearing.

Has anyone experienced this? If so, how did you overcome it? I’ve reached out to Support but wanted to cover it with the community as well.

Jamie Favreau

The Bullet should have come with extra spacers of different thicknesses to be used to adjust the clearance between the drum and the faceplate.

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Hey Warren,

Thanks for the recommendation. If I’m already using the two extra spacers should I pick up more, or might there be something else wrong?


A couple thoughts-

Just to confirm: do you mean the 2 spacers that were (I’m guessing here based on my own Bullet V1.5) factory installed? or that you already inserted the 2 spares packed with the roaster? The spares are provided in case you run into the need for adjustment, but if you now have 4 spacers installed there is likely a different issue.

  • is the scraping sound from the front of the drum? if it is…
  • have you confirmed there isn’t any debris/broken beans between the drum and the face plate?

If there’s too much space at the front it will allow small beans to drop into the gap where they make a horrible racket till the front plate is removed and the broken bits cleaned out

  • is the drum shaft seated all the way forward into the bearing? if it isn’t that leaves the possibility the drum is rubbing at the rear

If the sound is from the rear, I don’t have any personal experience digging into that but you might check the drum-mounted cog belt pulley on the rear of the drum shaft to confirm it isn’t rubbing against the rear plate. Or even possibly contact between the motor-mounted drive pulley and mounting hardware (belt tension adjustment has changed since I received my V1.5 so I’m not familiar with your configuration).

And just as a point of reference I have a little scraping noise from the drum lightly rubbing the front plate for a about a 20-40 sec as the roaster Preheats, then the sound disappears. Increasing the spacing to stop that noise lets small beans drop into the space during a roast so I learned to deal with it.



Did you check that the set-screw for the handle is not protruding in the door? make sure it is flush with the door frame.

I’m experiencing the the same issue. Once the roaster is heated, I start to hear grinding at the front. I have checked the set screw on the door handle and removed the face a few times to clean any stuck beans. I actually had the roaster drum stop about 1 minute in on a roast. The drum was not slipping but appeared and sounded like it was stuck. I was able to push on the bearing with the back of hex tools furnished with roaster and alleviate the systems for a second. It appears that I may need the spacers described in this thread. I will check the tension on the belts too. I feel like the shaft that rotates the drum has to mush play and moves front to back too much, hence why I think the spacers are needed. When I checked the bearing it appears I only have one spaces (washer set behind the bearing). I can not find other spacers manery I lost one, but do not remember extra’s in box. Any input would be greatly appreciated . Thank you. Did spacers fix the problem?

Was this issue resolved somehow? Experiencing the exact same problem as described in the post.
The Bullet has been working fine up till now…

Best regards,

Did you do any cleaning / adjustments prior to this happening?
If the scraping is coming from the front it could mean adding a shim (see the manual). Could also be beans under the drum. From the back of the roaster check the big drum pulley is not too close to the chassis.

Thank you for the input.
I have just started roasting on the bullet so no deep cleaning done yet. But I will open the machine up and try the suggested options.


I am experiencing the same scraping on the front of the drum. Has anyone solved this yet? I didn’t receive any extra spacers so I’m going to try to move the rear spacer to the front to see if that helps it.

The drum expands when heated. Unfortunately the drum and the drum shaft don’t necessarily expand equal amounts at the same time. Those tiny changes will be different between preheat and when the drum is charged and when the roaster is first started up. So you need thermal equilibrium to be sure the scraping doesn’t just fade away. The following has worked for me but of course YMMV.

Adjustment requires either…

  • Very fine adjustment of the face plate position. First check the back of the face plate for scrape marks- that indicates the direction the face plate needs to be moved a tiny fractional amount. With the face plate back in place and the 6 screws loose (loose enough to move the face plate but too loose will make it hard to tighten the screws without losing the adjustment). Push the face plate in the direction of the scrape-marks on the back of the face plate as far as the screws permit. This is a finesse adjustment; massive force doesn’t help. If this fails to stop the scraping noise then you’re back to adjusting shims (the step below).
  • Adjustment of the number/thickness of shims pushes the drum toward the rear of the drum housing (and away from the face plate). E.g. replace a thin washer with a thick washer supplied with your Bullet or possibly add a thin washer to the stack. If the shim stack is too high you will dribble beans out the front of the drum, so the process is to reduce the thickness of the shim-stack to the least that also prevents scraping. Keep in mind you may have to clean the shims… roasting oils can add to the thickness of the stack (though that ought not cause scraping).

If there was no scraping noise when you first got the Bullet, you shouldn’t need to adjust the shim-stack. The 1st step above ought to do the trick.


Thanks for your input. Before reading your response I proceeded to add too many shims up front and leaked beans out the front. Just replacing the original washer with a slightly thicker washer did the trick.

Great! Ready to roast then.

Those shims are precise… held to exacting tolerances. Not the usual ‘washer’ they appear to be. Takes very little to make it work as intended. If you don’t mistakenly lose a shim (been there; done that) you should be good for a very long time.