Which Engine Oil should I use ?

[Trigger]

.... as long as it is to the right spec, I am happy.

Trigger, I think you could have unwittingly struck the metallic pin squarely on the cranium here.
What is the right spec? Oils have changed vastly since the bikes were new 40+ years ago.
The original specifications for my 400/4 call for an SAE 10W-40 oil of Service SE Grade. Nowadays this is referred to as the API specification; in 1977 SE was the highest specification available. My understanding is that within reason the later higher specifications supersede the earlier ones.
The Millers oil I referred to has a 'Performance Profile' of API: SG, SH, SJ and JASO: MA / MA2. The JASO classifications seem to be for motorcycle-specific oils. The Millers oil is suitable for off-road, on-road and track motorbikes, and is for use in motorbikes fitted with oil immersed 'wet' clutches. I am happy it is right for my bike.
If I look at the Triple QX oil in Greebo's link I see it is classified A3 B3 B4. These specifications are for car and light van petrol and diesel engines. They may be perfectly suitable for use in bike engines but I can't link between the different sets of standards.
So my choice is to stick with a motorcycle-specific oil. It doesn't cost me a great deal more, and as I only run the one bike the difference isn't multiplied several times. as it would be for others on here.
So, bottom line (literally), what standard/specification would you be looking for in your 'Trade' oil?

Yes Chris, it is a little confusing as they keep moving the goal posts with new numbers and letters.
Had a bit of time toady and found some strong glasses to read the small print.
10W-40 Semi Trade Premium has ACEA A3, B3, B4, API SL/CF, MB229.1
Mineral Trade has API CF-4: AC EC A3, B3
Back in the 90's we used Castrol GTX on every Japanese bike .

[Paulreade]

Just continuing on from this post, the Honda manual states sae 10w-40 castrol gtx. I haven't done any further research as yet as I won't change the oil for 2-3 months. That said is the castrol gtx the, the oil that is generally advertised and used on cars etc ? Or is there a specific motorcycle gtx version ?.
I'm running a cb750 k6, it will probably run less than a 1000 ( gentle) miles per annum so looking for a decent value oil ( recommendation) - as I guess putting a premium quality oil in could be a waste and in addition may perhaps play havoc with oiled seals I suspect ??
Any advice welcome.

[Bryanj]

The 750 needs oil changes more frequently than the Porsche because the gearbox hammers the crap out of it

[adespin]

 So there doesn't seem to be a definitive answer as to which is the best oil for the cb750, should we use part synthetic or non synthetic, premium priced or economy, i'm just as confused now as when i first started to read this thread , and i was hoping there was a consensus as to the best oil to use,

[Nurse Julie]

So there doesn't seem to be a definitive answer as to which is the best oil for the cb750, should we use part synthetic or non synthetic, premium priced or economy, i'm just as confused now as when i first started to read this thread , and i was hoping there was a consensus as to the best oil to use,

You will get at least 28 different answers on what oil to use  and at least 100 different reasons why to use a certain type. We use Trade Premium 10w40 Mineral and Trade Premium 10w40 semi synthetic, not mixed together !!. Its as cheap as chips but does the job just fine. We find both are good, the mineral needs changing every 1000 miles, the semi, yearly. It is the frequency of changing the oil that saves these engines. Expensive motorcycle engine specific oil is a waste of money, its just oil companies advertising their wares hoping that motorcycle riding muppets will fall for it.

Edit......before anyone asks we use Mineral for running in and then on to the semi synthetic.

[Johnwebley]

So there doesn't seem to be a definitive answer as to which is the best oil for the cb750, should we use part synthetic or non synthetic, premium priced or economy, i'm just as confused now as when i first started to read this thread , and i was hoping there was a consensus as to the best oil to use,

You will get at least 28 different answers on what oil to use  and at least 100 different reasons why to use a certain type. We use Trade Tec Premium 10w40 Mineral and Trade Tec Premium 10w40 semi synthetic, not mixed together !!. Its as cheap as chips but does the job just fine. We find both are good, the mineral needs changing every 1000 miles, the semi, yearly. It is the frequency of changing the oil that saves these engines. Expensive motorcycle engine specific oil is a waste of money, its just oil companies advertising their wares hoping that motorcycle riding muppets will fall for it.

 try this brand,you sometimes get 2 for 1 offer
I use it ,and it works great
https://www.eurocarparts.com/ecp/p/car-parts/engine-parts/engine-parts1/engine-oils/?521776011&1&cc5_245

[Green1]

I don't get why people worry about what oil they should use.
Cheap as chips and change often. they will out last you and I.
Oil in the 70's was crap and they lasted forever.

[philward]

I agree - I think we all focus too much on different oil makes. Most reputable brands will be fine provided its got the right viscosity

[Green1]

Just to confuse things more my new van has just had its first service at 21000 miles and the manual states that viscosity is not important but quality is.

[Rob62]

Straight forward semi synth 10w 40 motorcycle oil for me..... any brand as long as its from a reputable supplier (ie not re packaged spry crisp-n-dry) 

[Green1]

Doesn't Honda say 20w 50 for the 750. 

I do run both the 550 & 750 on Semi 10w 40

[K2-K6]

The viscosity for all of these Honda engines is 30 when hot, and most other petrol engines from the 1960s until well into this century.

All the multigrade specs do is cover ambient heat range.  As an example 0C degrees ambient would be served by 20w in Honda's own published data.  15w will take you down to minus 5C and 10w will get you down to about minus 15C.

The "w" viscosity (well I don't think it's eventually viscosity at all,  more the ability to crank the engine at a certain temperature at starting speed) and the hot viscosity are nothing like the same measurement so that when you delve deeper it all gets quite weird.

As already stated though,  oil condition trumps virtually everything on these engines.  It really has no impact what the oil costs originally if it's diluted/contaminated to a point it doesn't maintain component separation.

[Trigger]

You old boys worry toooo much. A change is the most important thing, I can't tell you what i use, its a Trade secret . W stands for Winter 

[Green1]

I thought W was for wallpaper paste Iv been adding 10% to 40% oil 

[Trigger]

Yours sounds like it is running on wallpaper paste