Hi, just replacing my cam tensioners and bearings on my TC88

The rear Outer bearing came as a kit with bearing, shim inner and a little O ring. All is clear but can see where the O ring goes in relation to the cam. 

even the manual doesnt mention it. cant see where it fits and its holding me up. Any ideas? Sorry i dont have pictures.

By the way, its a 04 carby and it had the crappy inner cam bearings made by INA. Now has torringtons.

Tensioners were less than 20% worn. at 54k km's. prob didnt need changing, but got done because i had already stripped it down. Adjustable rods made the job easier

I know stuff all but is it for the oil pump?

The o ring slips over the rear cam drive spigot up to the inside shoulder to centralize the inner thrust washer on the shaft prior to installing the inner bearing race on the cam.

Thanks hoodeng. Thats what i figured, just needed confirmation. And there wasnt one on the old one.