Just wondering what v belts people use, is it genuine yam only or will a jt belt Be ok, I will probably having to swap it over later in the year at the 12000 mile service interval.

It’s not just the belt at 12000 miles its belt / rollers / sliders and transmission case gasket .
https://www.ebay.co.uk/itm/184647384277

Fit genuine parts and they will last for the next 12000 interval , cheap belts fit and hope they will

Belts.. OE or at least OE Supplier... Yam Mitsuboshi, Honda Bando - and note rotation direction... OE weights or Dr Pulley?
https://www.fowlersparts.co.uk/parts/59 ... 300/clutch
I'd just grease the gasket rather than replace... It's not oil side, never had to replace one when taking off the belt cover on any if the scoots i've owned.

DrPulley weights/rollers/sliders thingies are almost certainly worth getting - might improve acceleration, and they do last much longer.
Belts are confusing - there are lots of scare stories about utterly useless replacement belts, so I tend to stick to OE. However, someone on here bought an aftermarket belt from wemoto.com, which has worked well so far (and is half price).

Mine was done last year rollers and valves did not need doing, had Doc Pulley weight's on a Bergman I liked them
but I think the X-max transmission is fine as is and would likely stick with the org rollers if they need changing.

Hi all I fitter a jt max belt from wemmoto on my kymco400i at 19000 miles now have 26000 miles took off the cover last week just to inspect all perfectly fine the belt cost 58 quid an original costs 150 to 180 quid wemmoto say its equivalent quality to OEM so should last at least 12000 miles my previous belt done almost 19000 miles