Oil change - will this cause issues?

[fazerscotty]

[quote author=fazerscotty link=topic=23009.msg265730#msg265730 date=1502133326]
I've been following this thread from the start and I agree with a lot of the sentiments.  :lurk
In the General Aviation industry, we deal with a huge range of oils, like the motorcycle/car argument there are a lot of individual tastes as too where the money goes. The usual oil in use in the UK, (in flying training establishments) is a grade known as W80. There are grades higher than this (W100, W120 & W130) and depending on ambient temperature depends what goes in, i.e. some customers will operate with W80 in the winter and W100 in the summer. Add to the mix, the recommended oils for breaking in an aircraft piston engine (which are known as straight oils with no additives) in the same grades as above and you have a good idea of some of the conversations that take place. I've had customers request the use of 15W50 (aviation grade) as its "a good all rounder" but I've also seen cylinder damage occur in engines using this oil.
So - oil - its a personal thing, like salt and vinegar on chips.
However, in 35 yrs of owning and riding bikes I've never bought a bike specific oil (mainly because I couldn't afford it!) and I've never had any clutch issues either (and the bikes have included most of the Suzuki GS range, Honda singles and twins, GSX1100FL, FJR1300). Depending on the mileage, depended on the grade used - but the GSX for instance was running happily on 20W50 car oil and had 95,000 miles on the clock.
Currently I have a Gen 1 Thou and a VT750 Shadow, both with Asda's 10W40 Semi-synthetic (car oil) in. Both get changed twice a year as a minimum or more if the mileage calls for it. 20,000 miles and 3 years since buying the Yam and not an issue - or have I just been lucky?  :rollin :rollin

How can you not afford oil? Compared to fuel prices between changes - it mealts down to nothing. Even disregarding that - how much more does motorbike specific oil cost compared to a cheap car oil? 1/2 of a petrol tank price?

I've had bad experiences trying to skimp on oil, so never do so. Always go with motorbike, fully synth oil. It costs about the same in the long run - since it allows for a bit more miles between oil changes, but the main reason for using it is a peace of mind - if anything happens to the engine/clutch, I'm certain it's not caused by poor oil.
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Affordability? At that particular time in my life, money was non-existent. To the point I was using 2nd hand tyres on the GS650 I was using at the time (removed from Police BMW's with 5mm + tread left), in order to keep riding to be able to get to work savings had to be made. You obviously did not read the rest of the post, with regards to the lack of issues based on the experiences gained whilst not spending money, which I did not have at the time.
To really wind you up, I semi - retired that particular machine in 2002 with around 65,000 miles on the clock - most of which had been done with car grade 20W50. As I cannot leave things alone, I have stripped the engine to find the internals in very good condition for a machine built in the 1980's. It will be going back together as a resto project and I will be putting whatever oil I choose in it, as it is my choice, based on my experiences and my skills as a qualified aircraft piston engine engineer. (And that qualification and experience covers Radials, Rotarys, Flat 4's, 6's & 8's, Inverted in-lines, V's, Air & liquid cooled, Wankel rotarys, in both 2 stroke and 4 stroke styles!)
I will more than likely, do as the OP asked, as I can now due to being in a better place, put a poor quality oil in and use it as a "flush". It is a good idea. It is unlikely to harm anything unless it is full of the friction modifiers which have been mentioned in earlier responses. :lol