This is all the belt info I have at this time….have tried to sort and organize it a bit, giving sources of the info. You can see that there is more than one size listed for the same model in some cases…..makes life interesting! Polly, 11-5-10 Bob at Allyn: Original Necchi part number 726021000 - 13 3/4" belt fits: Supernova Julia, Ultra, Ultra Mark II, Lycia 522, 523,524,535,533,532,530,554, 525
Sheila: I did order a belt for my Julia from Allyn. It is a german-made Contitech brand, and the numbers on it are: FO 5 X 330 Li (note: Polly: I have the same belt on my SN Ultra-from Allyn) The julia does take a different belt than the Supernova. It's bigger, I think. Sheila
Don/Redfish: The listing for the SNU is 1334 which is 13.75" or 34.925cm. (Don’t know what catalog these are from.) Bob: Original Necchi part number 726031000 - 14 5/8" belt fits: BU Supernova, Esperia, Nora, and Lelia. Also Necchi 510, 512, 513, 515.
Don/Redfish: Belt # listed for (BU) SN is 1434 which stands for 14.75"(fourteen + three quarters) or 37.465cm. From Ron: Necchi Nora (Gray) (the one with the square door on the top that takes little black "hat" cams) 2-speed transformer with gray plastic housing and light/power switch on housing. Belt: Alphasew 1312 (13 1/2") Lug Belt -The belt is slightly longer than the original, but was able to be tensioned correctly. Nora = 14.75 = 14-3/4” (not sure where this came from; could be a different Nora model than Ron’s above)
Bob: Original Necchi part number 726003000 - 13 inch belt fits: BU Mira, BU Nora w/ transformer under motor BU Mira = 12 5/8" Lug Belt – At http://sewingpartsonline.com/necchi-bu-mira-sewingmachine-parts.aspx (I think I got these from their web site☺ BU & BU Nova- http://www.sewingpartsonline.com/necchi-bu-sewing-machine-parts.aspx shows 15” lug belt Sheila: Lelia 510 = one that Sheila has is an Alphasew 1438 (14-3/8”??)
Sheila: I have a Lelia 513 with a pink lug belt, with the word "alphasew" and the number 1438
Ron: Necchi Lelia 515 (Pink) - Belt: Alphasew 1514 (15 1/4") The belt fits perfectly. Machine came from a Necchi sewing cabinet. Made in Italy motor, pulley marked "5" - Motor mounted on metal bracket with no transformer, no speed switch. - Light/power switch mounted at machine head. OR: if the above doesn’t help…… TIPS ON GETTING THE CORRECT BELT: Measure the distance starting from the balance wheel around the motor pulley back to and around the balance wheel. Do this with the motor set to the mid-point adjustment position. OR
If the old belt fits and is still in one piece, measure it and go belt shopping.
Don’t know if this info will help but these are the notes that the folks at Allyn used to get the right belt: No sizes, just part numbers.