I tried the links to part providers on 1st page here, no luck.
Then I did a search on "go kart engine chain adjuster"; lots of similar devices.
Need to find one with similar geometry.
I also think the side-side motion stability is important, so it should nestle same way.
If not sized, then with bushings.
google search
https://www.google.com/search?q=go+k...APAOJ1elvTflRM
This one seems leading candidate
Kandi Engine Adjuster Assembly for 150cc and 200cc GoKart
https://www.ebay.com/itm/Kandi-Engin....c100009.m1982
I sent him the below:
Hi - My 2015 Tao Tao 150cc buggy just broke it's chain tensioner.
I'm looking for dimensions on yours, do you have a spec sheet? I could not see it.
I want to make sure the bushing portion fits between mine, if needed I'll put washers or loose bushing so no slack.
My bushing is 65mm / 2 9/16" wide, 25 mm / 1" dia.
Also, what size bolt goes thru that bushing, mine measure 7.79mm / 5/16" outside thread?
And Whats the chain tensioner thread size, mine measure 15.89mm / 5/8" outside thread .
Overall length is 124mm / 4.9" from centerline of bushing to top of big adj bolt.