I have had my 8900 for two years, and I've never had an issue with the timing after sewing multiple layers. I make a lot of bags, and sometimes that involves sewing eight layers of quilting cotton plus two layers of fusible fleece, or more. I do sew slowly when I have that many layers.

If you're on Facebook, you may want to reach out to Janome there. Another dealer or user may have a suggestion for you based on a similar experience or Janome may respond to the "squeaky wheel".

Have you checked the warranty you got to see if it explicitly excludes timing issues? I have no idea how the dealer would determine it is "operator error" that caused the timing to go out the second time. Sewing four layers of cotton wouldn't do it unless there's something else you're doing.

The early 7700 had that 'can't sew through seams' problem, they needed an adjustment in the feed dogs.
Show your tech with your fabric, what it can't do, and then try the same thing on a store 8900.

That's a lot of money to pay for a machine which won't sew 4 layers of cotton. How basic can you get? You really need to put serious pressure on this dealer to fix this issue or give you another identical machine. I am disappointed in that dealer. It's his JOB to take care of headaches like this which should not happen, even with a low-end machine, never mind an 8900!

This is where a good guild comes in to save the day. My guild has had two machine dealers close shop due to lack of business because of poor customer service after purchasing. It was always customer error or kept replacing parts until the warranty ran out then Oh so sorry, bye. The one dealer that stands behind her machines, gives excellent service and doesn't treat the customer as ignorant to not knowing how to operate a machine is thriving and she is in another town but supported by all the guild members.

I left my story on Janomes Facebook page. I will email my dealer now to see what can be done.

Good luck. Some days I cannot stand the attitudes of salespeople "after the sale"......keep us posted through all of your aggravation.

"Labor" should include re-setting the timing. It does where I work. Wow! I don't have much respect for your dealer.

The pen is still mightier than the sword...do a handwritten letter to the president at the home office. Mark the envelope personal. You will probably be surprised at the results you get. Operator error is a ridiculous cop out by your dealer.

I have an older Viking that will happily sew over that huge seam on jeans..with the help of one of those gizmos that evens out the thickness as you pass, going slow of course. But I also have a newer BL that is not stitching over an uneven thickness on the side of the pressure foot, not even under it. Took it in for checkup, still doing that, so it is going back and it better get adjusted, or whatever, or lookout Lizzie! I refuse to hear......my error, or not designed to do that!, or some other song and dance.....good money---- better perform!