- Mon Oct 23, 2017 9:04 am
#71677
There will be as many answers as there are brands of oil so here's mine.
For me, brand is unimportant. The change interval is short, they tend to run cool and the engine oil isn't getting mullered through a motorcycle clutch and gearbox like on modern bikes. For the same reason, the (in my oppinion very tenuous) reasons people give for using a "motorcycle specific" oil don't hold water for pre-unit motorcycles.
So, they usually specify multigrade 20w-50 and this is what I use when I can find it. It's getting harder to fidn now as it's used in older vehicles but the grade is sufficiently good for the bike. I don't go out of my way to find it though, in the UK you can buy "specialist" 20w-50 for older vehicles but it's expensive, I go for the big plastic drum from an agricultural suppliers. Usually comma brand but again, I'm not fussy, I strongly suspect it all comes out of the same tap.
In the UK, a lot of people use 15w-40 because it's easier to find and often for very ill defined/thought out reasons like someone has convinced them they need to use a "motorcycle specific" oil (you'll struggle to find a 20w-50 with a picture of a motorbike on the bottle). However, you live somewhere hot so the slightly higher viscosity might suit you better. I do notice that when it's very cold here (minus figures) the 20w-50 can get extremely viscous. So for the winter I'll sometimes switch to 10w-40.
In fairness, mine in particular seems to use a hell of a lot of oil (particularly before I put the styandard oil pumps back in) so for a while I was throwing pretty much any engine oil I had lying about in there. I doubt it makes much difference to be fair. Better to use cheap oil and change it frequently than to use expensive oil and be reluctant to change it.
One thing that occurred to me in all this is that they DO burn oil and a lot more so than modern bikes. When I drain my bullet the oil is black, when I drain my honda, it doesn't look much different to when it was put in there. So to my mind, a diesel engine specific oil makes a lot of sense. These have a much higher level of detergent in them.
Primary drive. As our hosts suggest, I use ATF in the primary on my bullet and double the change interval because ATF is designed to take a hammering and tends not to froth up. I also use ATF in the forks for the same reason.
The gearbox is full of 00 grade grease, you top up the level with engine oil. Changing the grease is a deeply unpleasant job I avoid like the plague. In facrt, I've never routinely done it, I have had to go into the gearbox of my bike to fix something twice so far, I did the grease at the same time.
