Forum

[Wheaters]

The Bullet series are always posted as needing 20W/50 oil. Does anyone here know if there is any experience of using a slightly less viscous oil? It might give the oil system a slightly easier time if scavenge pressure was too high, especially in very cold starting conditions.

(I'm not going to try it in my bike, it's fine as it is, thanks).

[stinkwheel]

I genrally throw whatever is lying about in there. It doesn't stay in for long anyway. So that will usually be either 20w-50 if I've been able to find it but often 10W-40 which is what I use in my jap bikes.

I think there's probably a balance to be struck between too thick to pump around and thick enough to stay in the engine. I keep a cycling water bottle of oil on the bike for topping up after long runs. In sub-zero conditions, it is noticeably quite hard to get the oil out of said bottle and into the bike when it's 20w-50 but less-so with a lighter grade.

I do wonder if 15w-50 is a good compromise. Just as thick at operating temperature, slightly thinner in extreme cold. You can also get it cheaply for diesel engines which means it has a high detergent content and as such is probably better equipped to deal with the degree of carbon produced by our bikes. That said, are many bullets going out in sub-zero conditions? Mine is probably one of the few and even then, only a couple of times a year when I go to winter rallies, I can afford to wait for it to warm-up.