I've used their Top Dog diesel oil before, contacted them to see what oil to use for a new rebuild and they said this. Found it fine in use nothing to complain about.
I used the Top Dog in my XT600 - all this talk about improved shifting on bikes, I've never noticed it....except for this oil. Turned a nasty knotchy gearbox silky smooth.
Speaking to Gulf Western today about ZDDP in oils, they suggested I consider their Top Dog range
You could also consider our diesel engine range which also carry API SL or higher petrol engine performance and have zinc levels of over 1,000-1,250ppm (0.10 – 0.13%)
Top Dog XDO 15W-40 (mineral) has around 1,100ppm zinc
Top Dog Global Mineral 15W-40 has around 1,250ppm zinc
Top Dog Global Plus 10W-40 (semi-synthetic) has around 1,250ppm zinc
Good honest answers from Gulf Western.