Oil to use cl77

[CliffC]

Down,
Sorry to hear about your Father. If it's a CL you are talking about I would recommend going to the CL topic and I'm sure you will get more hits there than anywhere else. Cliff

[jambretta]

Use Non detergent oil. If it’s labeled for wet clutch motorcycles it should be ok. Why Non detergent? Bc there is no oil filter membrane. Detergent suspends the junk for the filter membrane to work. The Centrufugal filter needs non detergent oil.

[Tim Allman]

Use Non detergent oil. If it’s labeled for wet clutch motorcycles it should be ok. Why Non detergent? Bc there is no oil filter membrane. Detergent suspends the junk for the filter membrane to work. The Centrufugal filter needs non detergent oil.

Detergents and dispersants are added to motor oils to keep combustion products, the stuff that turns oil black, suspended in the oil. The alternative is to have these deposited on all of the internal surfaces of the engine, including the oil channels. If a detergent oil is used, the impurities are removed at each oil change rather than building up as a black goo. Note that filters, paper or centrifugal, have no effect on this type of impurity. The combustion products are initially dissolved in the oil but as they react with oxygen in the very hot internal engine environment they can form very fine particles which will then grow into black goo by sticking to each other. This stuff can clog a paper filter if the oil is not changed regularly.

Some people recommend using the SAE 30 non-detergent (ND) oils sold in hardware stores for lawn mowers. I don't use these oils even for my lawn mower and certainly not for my Superhawk. They are non-detergent to make them cheaper, not better. In the case of this oil sold locally it isn't even labelled as motor oil. Interestingly the high price of $12.00 CDN doesn't reflect the low quality. If you venture beyond the hardware store to find a high quality ND motor oil you will have a hard time finding something suitable. Racing oils may be ND but for various reasons are seldom a suitable choice for road bikes. There really is no down side to using modern detergent oils in our old bikes.

The comment about using an oil suitable for wet clutches is bang on but the rest of the comment is incorrect. Neither paper nor centrifugal filters remove the stuff that turns oil black but both are good at removing metal particles. The effectiveness should be clear when you clean out your centrifugal filter. The residue consists of very fine and grey metal particles that would be removed with or without detergent.

There's nothing particularly special about the engines in our bikes and they don't require anything special in the way of motor oils beyond being suitable for wet clutches. Synthetic oils won't hurt but are unnecessary. Diesel oils can also be good choices. I've been using Motul 10W40 which I can buy in bulk but there are many other choices.