Janome 134D Overlocker

Check with your local Janome dealer, or even a sewing machine repair shop may have them.

HERE IS A FREE COPY OF THE MANUAL AT THE LINK BELOW:
WWW.JANOME.COM/EN/SUPPORT/RETIRED-MACHINE-MANUALS/
THEN CLICK ON MY LOCK 134D
I HOPE THAT HELPS.
ALSO THEY HAVE A ONLINE SUPPORT SITE AT:
WWW.JAMONECOM/EN/SUPPORT/
GOOD LUCK.

on the top head

Typically, set all your tension knobs to 4

my overlocker is a janome and i use generic overlocker needles; these are all rounded, not flat on one side. i hope this helps

go to this link and i think your manual is the first one on the page.
Janome Mylock 234D overlocker Google Search

While the ML134D is a very good entry level overlocker/serger, for coverstitch you will need a different or dedicated machine.
Janome has recently introduced a new model that is a combined Professional Coverstitch/Overlocker it is model 1200 D (Link) and is truly amazing in the diversity of stitch options
Their other coverstitch only machines are the CoverPro 900 & 1000 www.bargainbox.com.au

make sure the needle is pushed in properly.

You may need to purchase a Gathering Attachment
Part No. 200 217 101

BUT be sure it is suitable for your model first
(I am unsure which one you have)

Thread tensions are set at manufacture to all = 3 for standard work, your manual is generally helpful for many answers.

The "Janome Overlocker Sewing Guide" is a very detailed publication and has this to say about Gathering without any additional attachment.

Follow the link and you can view the instructions online
http://www.sewingonline.co.uk/instructions/janome134d/