The Honda Owners Club

Hello Forum

I have recently purchased a 1000Z with 27,000 on the clock and I wish to change the oil, and use the best modern equivalent I can, however I am not sure whether semi-synthetic oil (eg Silkolene Comp 4) would be suitable as the bike was produced in a mineral oil era and I have been told that synthetics could cause clutch issues on this older bike. Also have heard that some people use 20W/50 however the Honda manual states 10W/40.

Appreciate your input, suppose this advice is relevant for any late 70s/early 80s machine not just a CBX.

Thanks

Andy C

I have been informed that 100% mineral oil is the best and I believe 10W40 is also correct.

Cheers Witch

I wouldn't use semi-synth in an old bike.

You can still get 10W/40 mineral oil. I use Rock Oil in my 500/4s.

I have used both fully synthetic and semis in older bikes without any problems. My 36 year old CB350F and my 19 year old VFR400R both use fully synthetic oil. I generally run in engines on mineral oils before replacing it with a better quality oil to promote a quick bed in of the rings. When I was a Honda mechanic we used to have a lot of bikes in the workshop with top end failures and I wonder how many of them would have been prevented with modern oils. The beauty about modern synthetic based oils is their ability to provide lubrication as soon as the engine is started when most wear is produced unlike mineral oils. The extended temperature operating range of synthetic oils is also of great benefit to air cooled engines.

Regards

Chimpy

Is it an Urban Myth then about the friction modifiers and wet clutches?

SteveD CB500F wrote:Is it an Urban Myth then about the friction modifiers and wet clutches?

Hi Steve

I think a lot of the concerns came about when synthetic oils first appeared and gave problems with wet clutches. As they were designed for cars with dry clutches it was probably not too surprising. The bike specific synthetics that are now available can still give problems with some aftermarket clutches (generally the ones that use kevlar plates) but I've never had a problem when using genuine Honda plates.

It's certainley not a myth and I'm sure many people have had problems but there are probably other factors to consider as well. Most of the time people take an old tired engine and put synthetic oil in and then complain of clutch slip. The fact that the clutch was on its last legs to start with never crossed their minds.

All the single cylinder OHC C50 type engines that I build for people run on synthetic oil even though the engine was designed in the early 60s.

Regards

Chimpy

In the trader section look at opieoils from oilman who supplies to the trade and to public. They can advise and supply with HOC discount to boot.

The bigger problems come trading down from synthetic to mineral that can cause damage. So dont do that. Mineral up to semi-synthetic should not cause issue and indeed both my 20 year old and 11 year old VFR750's run on semi synth. 10w40 is the grade recommended and is readily available so use that. That provides better lubrication at cold which is when any frictioanl issues within the engine are likely to occur.

Do Not Use magnatec or similar as that sticks to surfaces which is where clutch issues can come in.