koolaid_kid wrote:
dadgonebroke wrote: I've heard some people mention that using synthetic oil in the motor seemed to make the clutch slip. FWIW.
A valid point, although not exactly correct.
You cannot use oils that are "Energy Conserving", they will make your clutch slip. Most automotive oils are like this, which is why I use Rotella T 15W-40 diesel oil in my bike. Diesel oil has the added benefit of extra sheer protection, which makes the gears in the transmission happy. Synthetics are fine as long as they are not Energy Conserving.
MajDSaster, what oil are you using?
+1 Your clutch may need to be adjusted, but the wrong oil can also cause slippage, but not because it is synthetic, simply because it is the wrong type.
The ingredients in oils have changed over the years. For example, today's Castrol GTX oil (and pretty much all other AUTOMOBILE oil) is not the same as it was in the 1980's. Back then it worked great in KZ bikes. But, things have changed. Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engine components from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers." These work fine and offer good protection for normal AUTOMOBILE engines. However, today's AUTOMOBILE oil "Friction Modifiers" , particularly those in "Energy Conserving" oils, are destructive to wet clutches. KZ bikes (and many other brands) have wet clutches. As a result of these oil chemistry changes a distinction needed to be made between those oils which are suitable for wet clutches and those which are not. That distinction was documented by the Japanese Engine Oil Standards Implementation Panel (JASO). JASO developed a number of different oil specifications for different applications. The specifications that apply to 4 stroke motorcycles fall under the "4T Specifications." Within the 4T specifications the "JASO MA" class oils are specifically formulated for 4 stroke motorcycles with wet clutches, so you should use oil that has "JASO-MA" marked on the container.
There are synthetic, semi-synthetic, and non-synthetic oils that meet the JASO-MA standard and any of them will work ok. Rotella T is one of them; Mobil-1 Racing 4T is another (it is fully synthetic); and there are numerous others. However, using oils that are not designated as meeting the JASO-MA standard is destructive to KZ clutches. Ed
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