PTO to Deck pulley size

[Newguy]

I have a Yamaha YT 3600 and cannot find the size of the belt or type of belt that goes from the PTO clutch down over the two front pulleys and then back to the mower pulley. Someone asked in this form but they really wasn’t an answer please help.

[Newguy]

I have the JA1 belt part number but they are non available anymore.  Basically looking for aftermarket replacement or another manufacturers belt that would work is anyone knows.  Thanks.  

[Newguy]

OK, so I just use an extension cord wrapped it around the police took a measurement and multiplied it by two bottom line 1/2 by107 inch drive belt works perfect.  Hopefully this topic helps others