I have a Riccar Model 706 The thread keeps breaking.

RICCAR R950 Instruction Book

Riccar sewing machine manuals

Sewing machine Riccar Super Stretch 505

Even if it's not your model machine, the threading instructions and basic use would be similar.

Install a brand new needle (confirm it is installed facing the correct direction).

If it still doesn't pick up the bobbin thread, the machine is probably out of time. Search for sewing machine timing or take it for service.

Verify you are using the correct needles for your machine. Some needles vary by a fraction of an inch but will make a big difference in serging success.

Remove all the threads from the machine.
(Always cut the threads below the spools, raise the presser foot, and pull the threads DOWN through the needles--Never pull up!)
ALWAYS RAISE the presser foot when threading.
Be sure to always thread each thread in the proper order--threading out of order will usually fail.
Rethread from the beginning and give each thread an extra little tug when threading the tension disk.

If a thread breaks, it is usually less frustrating in the end to remove all the threads and rethread from the beginning. Trying to rethread a broken thread will most likely cause problems.

Have a look HERE for basic Troubleshooting.
Bargain Box

sewusa.com has threading diagrams

or go to the riccar website & enter the site & in the search box at the bottom put in manuals & then on the page to the left look for the product manuals & then go to sewing machine owner manuals & look for model number RM 540,,,it is there

Try looking for a manual for your machine here.
http://www.riccar.com/help/manuals/
If your model number isn't listed try looking for a similar model or the number nearest to your machine.
Usually, sewing machines of the same brand thread in the same way. Hope this helps!

Here's a manual for the Riccar 2910, it should be similar to your machine.
http://www.riccar.com/ftp/whitepapers/2910-Owners-Manual.pdf
Threading is on page 13 and 14 of the manual, I think, Have a browse through it. Hope this helps!

Do you have your owners manual? I should tell you what tension to use for each type of material. If you do not have the manul, google riccar.com, sewing machine model ie.706 manual and it will download it for free.

Oh yes. GRRRRRR is the word!!! I hope I can help.

In many cases, breaking thread is caused by the upper tension being too tight, so that's something to check.

Another thing is to change your needle. If it's at all bent it can break the thread.

Third thing is to make sure you're using new, high quality thread. Older thread breaks more easily, especially if it's been in the sun.

Finally, clean and oil the machine. A bit of lint in the bobbin area can do all kinds of havoc.

Hope this helps!!

Glancing through the manuals at Riccar's website I do not find a model 440, though there are models 404, 410 and 414. One of those manuals is likely close enough. While it could be a tension problem, breaking thread is usually a result of a damaged or incorrectly placed needle. Also, if you are using old thread, it may no longer have the strength necessary. The first thing to do is replace the needle with a fresh one, making sure that the flat side is to the rear of the machine, and that the needle is fully inserted. It's also a good idea to remove the feed dog cover plate and remove any buildup of lint. Also remove any lint that may be in the area around the bobbin case and hook. Here is a link to the Riccar site where manuals can be downloaded: http://www.riccar.com/help/manuals/
Please let me know how this goes, I think we can get you sewing without taking the machine in for service.