Non-Detergent oil? is that necissary?

Hi so the garelli manual calls for SAE 30 non-detergent oil for the wet clutch. Could i use normal synthetic 30-40w motorcycle oil? I have some of the nondetergent on order. it is not easy to find. looking for a temporary fix here.

What do you think? would that work for a while? Since there is no filter does it even matter if its detergent or not?

Re: Non-Detergent oil? is that necissary?

Here's what that is about..

When they say non-detergent oil, they mean straight-weight (single viscosity oil) like SAE 30 etc - as opposed to standard multi-weight (detergent) automotive oil.

This is for two reasons. One, is that the automotive multi-weight oil is not designed to run in a gearcase. The action of the gears shears down the polymers in the oil, and will turn a 10W-30 oil into a 10W oil, in just a few hundred miles. The additives in modern multi-weight motorcycle oils fix this problem - so, they can be used.

- BUT -

There is another issue.. if the bike has been run for many miles with straight-weight (non-detergent) oils, it has probably built up oil sludge in the crankcase. Switching to a detergent oil after running without it, allows the sludge to break away from the parts, and clog the oiling system. On a moped, with an oil bath transmission, this is not that big of an issue.. but on engines with pressure fed oiling, it can lead to complete failure.

In any case, you are best off running with whatever the bike ran with in the past, as long as it was acceptable to the manufacturer.

Re: Non-Detergent oil? is that necissary?

Jason Luther /

thank you. i have been waiting for a decent explanation for a while now. i have been using 20w (detergant oil) in my riverside (30w drags) and was kind of waiting for the other shoe to drop.

Re: Non-Detergent oil? is that necissary?

ive been wondering the same myself. great explination, legendre.

Re: Non-Detergent oil? is that necissary?

a difference between non-detergent and detergent straight weight oils is that the non-detergent has a lower film strength and always carried a lower API designation. Lower film strength can be interpreted as less slippery. In days of yore we broke in new rebuilt engines on this cheap stuff to insure all of the parts would seat in.

Re: Non-Detergent oil? is that necissary?

One of the things that was left out is the condensed water holding capability.

Detergent oils hold the water that condenses in the gearbox in suspension. On non-detergent oils the water will stay in the bottom of the crankcase.

You can use non-detergent oil if you change the oil frequently.

If you use non-detergent oil and do not change it regularly the water will build up and build up. Eventually your gearbox oil will look like yelloy salad dressing. There will be so much water in it that it will quit lubricating.

In a four stroke the oil gets hot enough to boil the water out of the oil, that's why you can use detergent oil in the crankcase of a four stroke. The oil in a gearbox never get hot enough to boil the water out.

So.... non-detergent oil is best but you can use detergent oil in a pinch.

Re: Non-Detergent oil? is that necissary?

Oil weight and detergent are not related. Weight is weight, and detergent is detergent.

A multi weight oil is the weight of the first number i.e. 10w-40 is a 10w oil. At temperature it will only "thin" as much as a 40 weight oil.

Detergents are just that, the same stuff you wash your dishes with. Detergents keep dirt and water suspended in the oil, which then can be caught by the filter in a filtered system. A non-detergent does not keep it suspended and it falls to the bottom of the case/oil pan. You then have to clean the case/pan every xxxx miles.

So in an unfiltered system keep the dirt suspended in the oil probably is the best solution.

I buy my non-detergent oil at Walmart, right off the shelf....

Re: Non-Detergent oil? is that necissary?

2speed is right on the money. If you use detergent oil, the sediment that is suspended in the oil will be churned up and cause the engine parts to wear. It's not the kind of thing that's noticable, but will make a difference in the long run. Don't sweat it if you can't find non-detergent, but keep an eye out, or order it online.

Re: Non-Detergent oil? is that necissary?

detergents loosen up all the metalic bits and all the other crap and allow it to circulate .. So, unless an engine or a gear box or a transmission has a filtering sytem, you don't want to use detergent oils.. the continuously circulating junk will cause trouble.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account