Engine oil

[adrian58]

Looking to change the oil on my K2 soon and was wondering whats the best. Stick with mineral or go for full/semi synthetic. I know I put semi in my old Beema and it went straight past the rings, but kinda like the thought of engine being better protected with newer oil technology. Any thoughts experiences ?

[Seamus]

Whole can of worms there. Everyone and their dog has a view. Believe it has been done a few times before. I tended to use a 20/50 oil as recommended and change frequently. Halfords 20/50 or morris or any other classic oil would be fine.

[Bitsa (Ralph Wright - RIP)]

Agree with Seamus.They were designed in a time when engine oils were of  that caliba.
Cheers
Bitsa

[Lobo]

Agreed with above... only because my neighbour is an AA retiree, having done 33 yrs with them in their Tec / training department, and owns both a Douglas Classic + modern Triumph.

He recommends to stick with what the machines were designed to use, and pointed me to a Halfords 'Classic Oil' for my '750K2 - basically re-labelled good old Duckhams 20/50 Green stuff. If you change it often in accordance with the manual you presumably can't go wrong....

 This message will self destruct in....(!)

[K2-K6]

It's funny that everyone has quite a strong opinion about it.

I'd hold with the the others in that if you use oil of the type originally intended, you're unlikely to run into problems.....but can see your point of synthetic potentially offering an advantage.

One thing that is very clear to me is when looking at problems in engines related to oil, then by far the biggest I've come across is dillution with petrol on air cooled motors from too much running on choke...I think this is far more of a risk than the oil you choose......so if you do many short runs or start and no riding then you need to be very diligent in looking after oil changes.

Some of these engines have done very high mileage on original type oil, so it's clearly not the oil spec that is in any real way questionable.

[Bryanj]

Big problem is that most synthetics are designed for cars and have friction inhibitors in them which don't do a wet clutch any good at all whilst bike specific synthetics cost a damn fortune.

If you are going to be an "Average" classic bike owner and do less than 1,500 miles per year go to Tesco and buy the 10w40 non synthetic Diesel oil as it meets all the original specs and change it every 1,500 or annually

[adrian58]

Thanks for all your replies. Think I'll go for mineral 10 40 as it did cause problems in my BMW R80. Just thought SOHC Hondas' might like more modern oils. Just wondering why Bryanj says Diesel best ? Is it something in the specs ?

[Bryanj]

YUP mate, newer petrol oil has lots of uneeded additives whilst the Diesel has the one that makes it ideal for use in a combined sump and gearbox. Went through it years ago and the SAE specs we need are all in the Diesel one

[Waggles]

I agree with most here, frequent changes are, I think, the most important bit. I read a study once which measured oil viscosity fall ( as a sign the oil was 'wearing out' ) this was with 'ordinary' non synthetic oils, it found that most damage is done after 800 miles in a bike motor and put it down to the fact that the oil is shared with the gearbox. So the recommendation was to change the oil around 1,000 miles to 1,500. If you do that with Synthetic you will get through your bank balance quite quickly!

Synthetics may be better but they still get contaminated by blow by, condensation etc etc etc.

Couldn't help wondering why cars like the original Mini didn't have to change their oil every 1,500 miles as don't they share engine and gearbox oil just the same?

[Bryanj]

Look at the BHP per Litre for the explanation mate!!