Just when you thought that this debate was long gone........
Because I am currently thoroughly cleaning somebody's VHSB 34 LD, which has been laid up for some months, I was reminded of the variations in oils, in a roundabout way, by the stench & deposits on this carburettor, that has spent it's life so far on a TS1 x 60 mm stroke.
Now, I don't know what oil it has been used with, but I would like to know. I may find out in time. The other factor, of course, will be which fuel has been used.
That may be a bit too obvious, but the stench of this carburettor got me thinking & I guess that some fuels do deteriorate much sooner than others. I think that Shell & BP make good fuels, undoubtedly their DERV, but I rate Tesco Super Unleaded (Ultimate) & have found that it does not degrade anything like what I am seeing with the engine that I am working on.
Anyway, food for thought, as far as the quality of the petrol. Personally, I don't want to get into the debate about Ethanol or other additives. All fuels have 'additives' but not all are equal. I buy what I trust the most & steer clear of Supermarket fuels with the one exception mentioned, whatever I am riding or driving.
The other issue that's been debated, is the quality & mix ratios of the various oils. I realise that when images are posted about crankshaft big end failures, that before jumping to conclusions, all facts should be known. I have a lot of respect for anybody that builds their own cranks, races & maintains other race bikes, so when they advocate certain products, I'd be a fool not to listen.
However, we need to compare "like for like" when we make our conclusions.
For example:
I'm happy with a torquey, lower transfer & exhaust timing, long stroke Rapido using good petrol with Exol Optima @ 50:1. But I would not advocate the same in a much, much higher revving engine such as an RB or peaky TS. More revs = more oil. (Quite often, even then, the weakest link will be the cage utilised in the bearing. It is the cage itself that will be 'silver plated' but even then, quality of the cage varies dependent upon manufacture) Nor would I recommend the same oil & mix ratio in a near bog standard plodder.
So, I apologise for reviving this Post, but I wanted to communicate the fact that there are many variables that must be taken into account when decision making about oils & fuels.....