What oil is a substitute for Honda G4? Years ago we used to run Castrol in our ATC's, but I'm not sure it's good on quads with the wet well tranny's.

 

GN-4 is a pretty decent dino based oil for motorcycles IMHO.

Anyhoo, you want oil that has API rating SG or higher, and JASO rating MA.

It is the JASO MA certification that indicates the oil is OK for wet clutch applications.

There are many brands out there.

ReconRanger will probably chime in with specific suggestions.

 

First, some required reading.....

http://www.thumperfaq.com/oil.htm

Oils Well That Ends Well, Part 1 - Sport Rider Magazine

It's pretty simple, what you want to look for is an oil that is motorcycle specific, API SG/JASO MA. GN4 is a very basic petroleum oil. If I was looking for a reasonably priced replacement petroleum oil, it would be Maxima Premium.

The problem I have with Honda's oils, is that they are no longer SG, but are now SJ. This means that the anti-wear additive package has been downgraded so they can sell the same oil to street bikers with cat converters, and off-roaders:

"Fuel injected street motorcycles with catalytic converters restrict the types of
additives that can be used in an engine oil. There are certain performance
enhancing oil additives that cannot be used for environmental reasons. These
restrictions reduce the film strength potential that off-road high performance
4-stroke single engines require in an oil. This means that if you want the
best oil possible for your off-road machine, a general purpose or multiuse
motorcycle oil is out of the question. Why be restricted to the limitations of
an oil with an additive package designed for a catalytic converter when you
don’t have one?" http://www.belray.com/scripts/future...6-e27066d0d02a