Hey Fellas
My bike needs 25ml of oil every tank.

I've heard from a number of bikers that castrol magnatec (car oil) 10W40 can be used in a motorcycle.
Theres some guys in the CBR section using it.
viewtopic.php?f=28&t=1494&p=10046&hilit=magnatec#p10046

It didn't make my clutch slip but my gearbox wasn't changing so smoothly and I wasn't happy with it.

I've been topping up with Shell Helix HX3 SAE40 Mono Grade, API SF/CD
"Suitable for petrol engines fitted with conventional carburettors without blowby recirculation."
She feels wonderful now. Gear shifts are super smooth and engine going really nicely!

The manual calls for 10W40.
I'm wondering for my next oil change if I can use a whole lot of this monograde W40 oil and throw in a bit of 10W oil for good luck?

Why does it need the oil?

Solve that and you have a happier bike??

My mechanic has had the head off and he said everything is fine. He said it must be worn rings..

Then maybe fix the rings??

Did he compression test it, with and without oil.

Too expensive for me at the moment mate. Yeah he said compression is lower than it should be, but the bike runs great otherwise. It doesn't bother me mate.

Fair enough, money can be a right pain some times.

10/40 semi synth oil should be fine.

If it's burning it no need to use expensive oil.

Some car oils.. mainly fully synth car oils but even some semi-synth oils contain extra moly (friction modifiers) that improve gas milage.

However, these can and do cause the clutch to slip.

Car grade oil breaks down quicker than motorbike oil so don't use it for extended perious of time.

You could also try a thicker oil, like a 15/50 as these tend to reduce usage on older engines.

Neosophist wrote:Car grade oil breaks down quicker than motorbike oil so don't use it for extended perious of time.

Never heard that one before, my car does approx 20k between services.

They are different though, the car has a seperate geabox/oil whereas the bike is all in one, as Neo said car oil would not be beneeficial to the bikes clutch plates.