Uwe is correct it will tend to give you problems with #207.We used to sell them new years ago & had a customer come in wanting one for nylon halters & using #207,I showed him what we had & he didn't want to spend $5,000.00 on a new Adler & pointed to the Juki 241,I said we can try the thread & see what happens but I didn't recommend it for a long term.He says just to get started then go to a bigger machine,I told him he pushing it & might have problems.We I sewed on it ,it worked great.He bought it & was back in less than a week,he jammed it up.I guess he didn't hold the thread.We fixed it & showed him again how to hold the threads when first start.He came back maybe 3 wks later & broke the hook on it.So now he starting to understand what I told him & bought a Singer 97-10 for the large thread & kept this for the chaps & thinner sewing. Moral of story it's best to get the right machine for the job your doing or you'll end up spending more later .
The only problem with the model 241 is it doesn't have a bobbin case opener like Juki's newer model 1541S has & that helps prevent the machine from jamming up esp when your using large thread otherwise when you use #138 or thinner on this machine it should give you years of trouble-free service.