Engine oil

[Bodd]

I'm now at the stage of filling up my engine with oil so decided to do a little research about what the best oil is to use, as far as it goes I know nothing about oil types and properties and usually use the manufacturer's recommendation which my research tells me is 3.5 litres of 10w 40 mineral oil, but I have seen elsewhere and also on this forum 15w 40 diesel oil from Tesco (Carlube) being recommended, can anyone shed any light on this ? I have read this article but past experience tells me other people's experience will give me a better idea.

[matthewmosse]

I just cleared the shelf at our Tesco of that particular oil, they had it reduced to £2 a bottle (2l) from £8.

[Bodd]

They have 4.55L for £12 but is it the oil to use in my bike ?

[Dan]

I've always been under the impression that you should use bike specific oil as it is formulated to withstand the shearing effects of also lubricating the gearbox.  I use Rock Oil Gamma 10W 40, but it's a bit dearer than Carlube diesel oil.

I'm guessing you can get away with using car oil if you change it frequently?

[Bryanj]

The Tesco stuff has exactly the same sae spec as the original requirements, and being for diesels has additives ideal for the gearbox. The original change interval of 1500 miles also takes account of the gearbox use. Personally I always change both oil and filter every time as I don't believe in putting clean oil through a dirty filter and if you buy a few at a time they ain't expensive

[Bodd]

Thanks Bryan, I think it was your post I saw before about the Tesco oil, I will get some.

[Clem2112]

Bike specific oils were not in common use when these engines were designed.
I used to change the oil and filter in my 400/4 every 1000 miles back in 1978
Used Esso Superlube 10W/40 which was one of the few that had the viscosity that Honda
specified.
My bike covered over 30,000 miles from new in the two years I had it, never used a drop of oil and the gearbox and clutch never gave any trouble.
You could get 3 OE filters for a fiver and I paid about the same for a gallon of lube !

[K2-K6]

I don't feel that the gearbox makes that much of a demand on the engine oil.

Most gearboxes run oil for much longer intervals when they have their own oil and not shared with the engine. Gears have their design specific to the oil type they will run with from the thin stuff in auto boxes up to the EP oils for both gears and axles. These boxes are designed to run on thinner engine oils and only ever have one pair of gears under load at any one time, the rest of the gearset is doing nothing really.

The real degrade occurs from combustion by-products leaking past the pistons, the shorter the journeys the worse the oil will get over the same period, just smell new oil versus used to see how much petrol smell is in there.

If the bike is run regularly and gets hot for longer distances then the oil change intervals should meet the manual spec, short runs and you should be swapping it much sooner to avoid it being diluted and compromising the plain bearings.

[matthewmosse]

Open up your average diesel engine, there will be a massive lot of cogs driving the injection gear, or even pto stuff, so diesel engine oil is easily of the speck to cope with what gears need. Also every diesel engine I have opened up has used plain bearings just like the honda sohc ones, but as diesels are pretty harsh these bearings get worked easily as hard, probably harder. Mechanically I would think diesel speck oil is fine. I think I have been told it may have a higher detergent level but cannot see that making much odds if true. The only thing to worry about with oil of the right type  is clutch slip, I have had this from 1 brand of semi synthetic oil, but others have been fine, took a further oil change after dropping the slippy oil to get rid of the clutch slip, no other issues from it. I try to not mix brands when topping up but do shop around for a cheaper deal and I always change the filter with the oil, and have been known to streach service intervals sometimes, still got 180,000 miles out of an engine, pulling a sidecar before getting symptoms of gearbox wear in 1st and second. I used to only use 'proper' bike oil, but switched to cheaper stuff because A, the bike oil started getting ridiculously expensive, and B, every mechanic not actually selling bike oil to me told me for that age bike, you are wasting your money as it was developed for normal oil, not fancy stuff. The speck sheets agree.

[Dan]

Always happy to learn something new on these bikes. I only do around 1000 miles a year anyway on mine so I can save a few £ when I do it's oil change over the winter.

Is the diesel oil ok for more modern bikes, out of interest?

[Bryanj]

Simple answer----don't know, you need to look in your hand book for the specific bike what the S.A.E is and compare it to the oil package TAKE CARE alot of them have the same numbers but the letter at the end is important (Might be vice versa on that!!)

[Lynx]

Personally, I always run in with any old 10w40 mineral oil. Then switch to Halfords semi-synthetic motocycle oil.

[mick]

I'm using Halfords 10w40 mineral oil at the moment had no issues and asda have Castrol gtx 10w40 on offer at the mo for £13 for 4.5 litres  use that in my VTX happy days  cheers Mick.

[Greg65]

Thought I would stir up this old subject again, I know a lot is personal opinion but came across these people and thought I would canvas a few opinions.

https://www.ebay.co.uk/itm/10W-40-Motorcycle-Oil-4-Stroke-JASO-MA2-10W40-5L-Westway-Lubricants-/111704165494

Have been internet searching but can not find anything definite about them but hear that some major oil producers sell high grade oil bulk which is then repackaged in the buyers cans. As it has the JASO MA2 spec, £21 with free delivery for 5 Lts I thought it might be worth using given the 3,000 mile oil change schedule.

Greg

[Nurse Julie]

Where do you get it's a 3,000 mile oil change 🤔🤔🤔 1500 miles in all the service manuals. As long as its rated JASO MA / MA2, it doesn't matter which one you use.