Engine oil

[Steve1960]

Hi, Ive just bought a '79 Z1000 A2 and need to know if modern engine oils are ok to use , or does it need to be Mineral oil , as I obviously dont want to damage my engine , thanks in advance for any info,
Regards, Steve

[Garry.L]

General advice is any decent Semi-Synthetic as Fully Synth can cause clutch slip.

[zed1015]

Any decent 10/40 semi will do (Avoid fully synth unless it's Rock oil TRM20/60 for tuned or race motors).
Silkolene/Fuchs Super 4 works well.

[Steve1960]

Hey thanks for the prompt replies chaps much appreciated :-)

[chrisu]

any decent motorcycle specific 10/40 oil is fine . Semi synthetic fine - even Halfords own.
Fully synthetic a waste of money for a std Z.

[rickm]

Why is fully synthetic oil a waste of money?
If you don't get clutch slip then why not use the very best oil protection you can get?
I have fully synth in my J, have heavy duty springs so get no clutch slip, and know my engine has the best possible protection I can give it.

[Charlie]

There are lots of myths about using fully synthetic oil in motorcycle engines, most are perpetuated by forums such as this one, where everyone throws in their opinions which they believe are fact - but often are not.

Fully synthetic motorcycle oil will not cause clutch slip on any wet clutch engine - provided it carries the JASO MA or MA2 certification stamp on the bottle.

That shows it has been tested and approved for wet clutch use. Some oil companies such as Rock, Putoline etc claim JASO but do not carry any actual certification number on some or all of their products, nor do they have the official font shwoing it has been submitted and approved (google it if you want to see what it should look like)....basically that means they THINK it would pass JASO standard, but for reasons known to themselves, opt not to submit and pay for the official test/approval.

The cost of that submission is pennies in company terms. Cost should not be a factor in deciding whether a vital product is as claimed. Draw you own conclusions from what that could mean .....

I would not wear a helmet that a manufacturer thinks would pass the relevant standards, only one that has been submitted and tested - but each to their own. You pays your money and you takes your choice

The major advantages of fully synthetic oil are that it will stay in grade longer and not deteriorate as fast as a lesser semi or synth fortified oil will do - that means you can safely leave it in the motor for longer and it will continue to do it's job

Wider viscosity gaps are also possible with fully synthetics. 5w/50, 10w/50 10w/60 etc. Better protection in climate extremes or in engines that may run particularly hard/long and reach bigger temperature variances.

Having an oil that can be thinner on startup and stay in grade at the top end can also protect the motor better

As with most things motorcycle related, there are some manufacturers that are better than others. Motul and Motorex are the two that are used by, favoured by and used in development by more manufacturers and race teams than any other manufacturers (whatever may be on the race fairings).

There are lots in the middle and a few that sit at the bottom. Some (including one name you will all know) do not even make their own oil - they are just a rebranded oil made by other companies that you have never heard of, nor would be likely to use if you had....I dont really want to name those guys on open forum, but stick with the top two and you are certainly good to go.

[Charlie]

.. and yes, I appreciate that JASO did not exist when the Zeds were manufactured, and that they did run on what is by modern terms, a fairly crude oil product - but then again, they used to break down more often back then too.

You will (or should) use modern brakes and tyre compounds, why not also take advantage of better engine protection too ?

[needaz1100r]

.. and yes, I appreciate that JASO did not exist when the Zeds were manufactured, and that they did run on what is by modern terms, a fairly crude oil product - but then again, they used to break down more often back then too.

You will (or should) use modern brakes and tyre compounds, why not also take advantage of better engine protection too ?

Fully agree with all you say, too many opinions given as fact. The only fact I consider is that oil is the only thing that allows parts to work together millions of times at high temperatures that would otherwise be destroyed in milliseconds. Choosing the best for your application is just common sense. I continually have the "Harley recommended straight 50" argument and I continually point out that straight 50 was all that was available, and straight 50, is no different to 20/50 once the engine is up to temperature and Harley don't effing recommend it now do they?. My only observation is that the 5w and 0w synthetic oils do tend to make engines sound more noisy.

[King of Kings]

My old Zed back in the day ran for over 70k on nowt grander than Castrol GTX-20/50 Oh, and it never ever broke down!

[johny brando]

Why is fully synthetic oil a waste of money?
If you don't get clutch slip then why not use the very best oil protection you can get?
I have fully synth in my J, have heavy duty springs so get no clutch slip, and know my engine has the best possible protection I can give it.

PLUS 1 on the above.

[CAT3]

I spoke to Kawasaki some years ago about oil in my '76 Z900.
I used to use BP Visco Static 20W50 for years, but when that became obsolete I needed something else. Like many people I thought fully synthetic would be best, but the guy in their technical department said the best oil for my bike was a good quality, as in good make, 10W40 semi-synthetic.
The only difference that I noticed was when selecting first gear the gearbox didn't "clunk" like it used to with the 20W50 oil.
I've used Motul 10W40 semi-synthetic now for a good few years with no ill effects.

[zed1015]

There is nothing wrong with using fully synth in most engines BUT it is the roller bearing crank in these and others that fully synth is not friendly as it allows the rollers to skid at much lower rpms which causes premature wear.
If you are going to use fully synth in a Z then it must be specifically formulated for roller bearing cranks such as Rock oil TRM 20/60 .
The clutch slip thing is another issue and it has been shown that while not causing clutch slip it does show up plate wear and allow slippage much earlier .
This is the reason why people have experienced clutch slip when changing from mineral or semi to fully synth and then on changing back the slip disappears.

[PAULJAC47]

Sage advice i reckon zed1015,i just stick to a good classic mineral and change it often,never had a prob.

[wilsonsjw11]

Morris Golden Film, 10/40W like it says on a Z1 filler cap.
Regards
Steve