at the other end of the pricing spectrum here's a basic DIY unit, costs practically nothing, two bearings, very solid,
very reliable, this one's been running trouble-free for years.
The engine case thickness in front and below the front sprocket is 6mm. You can fit a 13 tooth
sprocket easily, but better with a 14 tooth where you lightly skim 2mm or so off
the casing with an angle-grinder to get clearance.
There's one milled with CNC on the yank site rigged for a 15 tooth sprocket but they'll find that'll be dodgy.
I wouldn't go with a 15 tooth because those clearance points on the cases are gonna have to be wafer thin to fit that size, and on deceleration the chain loosens slightly forward off the sprocket and it'll likely be clipping those thin areas, which would be bad news in the long run Jose...
AND AGAIN, IGNORE ALL THE TRIPE AND B.S. ADVICE on the yank .com site stating imperiously that a 14 tooth sprocket is "no good" because "the chain won't last" That's just ignoramuses over there blowing their own trumpets on stuff they know absolutely nothing about...
A 14 tooth #530 sprocket and O-ring D.I.D. chain setup lasts for bloody years and tens of thousands of kilometres without any signs of wear. I adjust the chain on mine about a mm maybe two or three times a year. But stay away from 520 pitch, it's too scrawny for a big heavy XS11 road bike.
