If it helps , I can always do a chain conversion kit for you as a local stockist just email us , as most of my 650 clients use chains now until their budget allows them to go to a belt system again (at that point, it’s good to change the pulleys, keep old ones as spare) If i ever find a way to source a cheaper belt in the UK from my traders, ill be stocking it on the website like crazy , has to be good quality , none of the china crap that snaps in 2 days.
There is actualy Gates 178T cdx carbon drive belt, its 5mm shorter and should fit.