Castrol Power 1 - synthetic or semi-synthetic?

[mrp192]

I have always used Castrol Power 1 semi synthetic oil in my 2015 Glee and 2022 DL1050.
I have used this as the mechanic at the dealer I bought the Glee from said, ‘it’s better to use semi synthetic oil in these engines, as they are based on old technology and they seem to prefer it to synthetic oil’.

He added that it would also be better to carry on with the old oil change limit of 3750 miles rather than the new 7500miles limit, that was introduced when Suzuki started recommending synthetic oil.
He also said under no circumstances mix the two types as they will adversely react and may damage the engine.

Now I took that all as good advice, and have followed it until I sold the Glee after 40,000 reliable miles and also with the 1050 after the dealer told me they use semi-synthetic oil at the first service.

Last week, I tried to buy some Castrol Power 1 from Halfords and noticed that the words semi synthetic have gone from the label on the back of the bottle.
I asked for assistance and the manager and I looked at the Halfords website, where under description it says ‘this synthetic oil’ and under specifications it says, ‘part synthetic’.
As he couldn’t confirm which type it was I held off and emailed Castrol Tech Help.
After having to email back screenshots of the particular oil I wanted to purchase they confirm that their Power 1 oil is ‘part synthetic/synthetic technology’. 

So can anyone explain what that means or alternatively recommend a different brand of semi synthetic oil I can switch to?

Thank,Mark.

[nigel s]

'22 650 owner here,no recommendation for fully synthetic in my owners manual,1050 don't know. Castrol ,also don't know.
The short change at 3750 is a must for me even though they say 7500.
I use this ,
https://www.ebay.co.uk/itm/334646718519?itmmeta=01HXSCJXEZ2W60SSQWSNYFZPX6&hash=item4dea7fb037:g:~WcAAOSwwN9jhjp6&itmprp=enc%3AAQAJAAABAPwqnGC4BskAD%2FPen%2BTjm5TrQgRDlsykFAJ3u8WXv2zVMT5FJawHcWDmbYAo0FzphXJgdqjA%2Bs0LfL%2FbRzYB6GCIwrdznFDTM3BJraNCliwDtvHA8iYyJKYKMabk%2FXOtNmVx%2FjTvYPIqEoX1htNJZOneVruLcIEaefYxdm0WnQftRlYmOdfF2dJDe6Dm0kXvY%2BkMvnrCZps95%2Fpxev7QPdkMtKHFqenE%2FtwRNfjYFNnURzscglXta7KSaZKRE1AiW68aiG6aeSaNjuqLLG6n3m%2FXbzw8Bx0FpIpxB7IlAzo8YsC9pAg87spNFCkwnGu9BpD6a8k89Q01WuORoT9Ojeg%3D%7Ctkp%3ABk9SR8rXy6zuYw
And have done for years over many bikes wanting semi synthetic with no problems.It has the right JASO MA spec.

[Barbel Mick]

This link from Opie Oils website mentions the renaming of Castrol oils.

https://www.opieoils.co.uk/p-727-castrol-power1-4t-10w-40-semi-synthetic-4-stroke-motorcycle-engine-oil.aspx#:~:text=Castrol%20POWER1%204T%2010W-40%20is%20a%20semi-synthetic%20engine,maximum%20protection%20for%20the%20engine.

Castrol Power1 Racing was/is the fully synth oil & will now be called 'Ultimate'.
The Power1 is still semi synth.
I have always used the Power1 & will continue to do so. I change my oil & filter at around the 3k mile mark.

[porter]

 I have used Castrol power 1 semi from new in my 2014 1000, change very 3-4k or now yearly and never had a problem in 45k miles. Don't think a Vstrom needs full synthetic really unless you want to leave it the full 7.5k miles.
I once worked with a bloke from Mobil oil for a few weeks and he said clean oil is the key, for the average driver use a semi synthetic oil and change it every 3-4k on a bike and 6k on a car, followed this ever since.

[Ianmc]

   I use Motul 5000 semi-synthetic and have done so on all three of my Vstroms since 2015,40k,35k,and nearly 1k.miles on the three bikes.I change the oil and filter every 5k.miles,simply as it’s easy to remember as in 5,10,15k.miles etc.etc.None of the three have used any oil between changes that I am aware of, and if they did it was such a minuscule amount it was not visible in the sight level glass.

[mr_diver]

I use whichever semi-synth known brand is the cheapest for 5ltrs 

Motul 5000 is currently on the shelf waiting for time to service the Varadero, I'll use the same in her GSX when it's ready to go back on the road if it's still the cheapest.

Castrol Power 1 = Semi-Synth
Castrol Power 1 Racing = Fully Synth

Fully synth is modified to reduce the sheering effects of unit construction engines (engine and gearbox in one oil volume)
Semi synth is designed to do the same but to a lesser level but at less cost than a fully synthetic oil.
(all the gears in the box - squeezing and ripping the long chain hydro-carbon molecules, synthetic esters are designed to reduce this effect - oil when well used for thousands of miles more viscous as the molecules have been ripped apart)

If you have an old 1960's BSA/Triumph/Enfield with separate engine & gearbox mineral oil in the engine it will be OK for 2.5-3k miles, but the same oil will be toast in the strom after 1000 miles - Synthetic in an old engine is just a waste.

I would put in fully synth if I was planning a long tour just to ensure she's running in quality oil for longer, but day to day it's over kill.

Honda Owners tend to stick to 4k service intervals even though the service manual says 8k - and that's for Semi Synth!
8k is an awful lot of abuse for the oil in a unit construction engine, I changed the Varadero's oil once at 5k and I won't be going that long again. 
Strangely my bike is supposed to use 10w30, 2 years earlier and the same engine design requires 10w40 - this is solely down to Honda's switch to a cheaper oil grade available to them for use in the factories - the design doesn't give a damn.

[purplebikeunicorn]

When you could get Shell Advance full synthetic for cheaper than its semi synth equivalent we stocked up, been using it in bikes from the 1980s to my v-strom - my v-strom doesn't use oil and realistically even the older bikes don't use that much when topping up (they're not British).

Whilst I've heard a myth that full synth in much older bikes causes issues, we've experienced none. Once the supply is used up, we'll go back to the Shell AX7.

Edit: If you need to stock up, Arnold Clark Autoparts has the full synthetic for £21.99 for 4L. Shipping unless you order over £50 though, but if you wish to stock up, might be worthwhile! My last 4L of AX7 semi cost £25 off eBay. https://www.arnoldclarkautoparts.com/products/shell-advance-4t-ultra-10w40-synthetic-4-stroke-motorcycle-engine-oil-pure-plus-4ltr-engine-oil

Oh, and you can click and collect, seemingly for free... Hmmmmmm!

[mrp192]

Thank you to everyone for your advice. Especially Barbel Mick for your post from Opie explaining Castrol’s misinformation campaign.
I will continue with Castrol as it’s available in my local Halfords where I can get a discount.

[nigel s]

Bennets special discount ?