Juki TL-98E Tension issues
 

I recently picked up a Juki TL-98E that is having a rather curious tension issue. The machine stitches fine at very slow speeds, but when I accelerate, the thread loops up underneath like there is low top-thread tension. Increasing the upper tension does not eliminate the looping, however, it only makes the upper thread break.

I have taken apart the top tension and cleaned between the discs, and I have set the bobbin tension to slowly drop when held by the thread. I have checked the manual and made sure I am threading the machine correctly. I am now kind of at a loss of what the problem might be.

does anyone have any ideas?

Have you tried a different thread? I only ask because I was so frustrated with my 2200 QVP Mini because the tension didn't seem to be behaving at all. I fried a different spool of thread and all was good. (Too bad I didn't try the different spool of thread before spending 2 afternoons, cleaning, oiling and being frustrated).

Have you checked the bobbin tension. After several years I had to loosen the bobbin tension.

I have a Juki TL98QE Which means it didn't come with the extension.

I can use coats & clark and connecting threads thread. Actually those are the only ones I use. Be sure to keep it oiled.

I have tried some different thread (Gutermann 120), and a couple of tension settings on the bobbin (I even backed it right off until the spring was visibly lifted away, then reset it)

maybe you can find help here
juki info: https://www.jukiclub.com/jukistraightstitchfmq/

It seems to me that. at higher speeds, the machine cannot keep up with the stitch formation. Perhaps the thread is too stiff or the needle is not the right size.

I have the Juki TL98QE and use it for machine quilting. I can use any thread I want. I haven't had it mess up because of thread type. I use a 70/10 needle most of the time. I bought mine used from a dealer and it was serviced and checked. So far I haven't had any tension issues but the foot pedal sticks once in a while in slow speed, no big deal right now. Juki's are fantastic machines. There is a Facebook group for Juki machines and lots of great info there.

I'd check thread and needle.

By the way I quilt with a size 16 needle. Works great for me. Juki machines are designed to go fast and it quilts very nice for me. That is the way I started quilting on it. Many years ago.

It might be a good idea to remove the needle plate and check to see if there are any threads caught in the hook or behind the hook. Sometimes thread gets caught in the thread cutter. One other simple thing is to make sure the bobbin doesn't have any thread dangling from the center or wrapped around the bobbin form the outside.