1981 GS450SX - Bringing it back from the dead

[Rich82GS750TZ]

Not sure where the countershaft sprocket nut is. I have the chain hanging on with some wire.

Simply, the front sprocket. (Drive Chain, not cam chain) If your drive chain is still on the bike and on both the front and rear sprockets, it's often much easier to loosen the big nut (I know I have a socket, can't remember the size, it's a biggun.) Bike in gear, someone standing on the brake pedal, to get that nut loose. There should probably be a washer with a tab folded over keeping it from loosening on its own. Just peen it back flat. Some L models do not have this washer, not sure about your bike.

[rottenprimate]

Simply, the front sprocket. (Drive Chain, not cam chain) If your drive chain is still on the bike and on both the front and rear sprockets, it's often much easier to loosen the big nut (I know I have a socket, can't remember the size, it's a biggun.) Bike in gear, someone standing on the brake pedal, to get that nut loose. There should probably be a washer with a tab folded over keeping it from loosening on its own. Just peen it back flat. Some L models do not have this washer, not sure about your bike.

Ah I see, good to know. It's in neutral and the clutch cable and rear brake are already off but I can stick em back on.

Oil question!! According to a website about motorcycle oils:

Remember, 10w-40 oils contain a lot of VIIs which tend to shear in your transmission, so I believe 10w-40 oils should be avoided. You can't use 10w-30 because of the friction modifiers. This doesn't leave much. Commercial 15w-40 oils are a good choice, because they have relatively few VIIs which are the more expensive shear-stable sort. Synthetics typically don't contain much of a VII package, so shear is not as big an issue with them.

My bike calls for 10w-40. Why would it call for 10w-40 if it was harmful to my transmission? I notice Shell Rotella 15w-40 and even 5w-40 recommended a lot. Any harm in using one of those? Where I live it never gets cold.

[Rich82GS750TZ]

Sprocket: bend back the locking tab first before you go through all that bother. You may get lucky. My nut was only on there finger-tight.

Oil Opinion: 10w-40 is fine but be sure to get motorcycle formula for wet clutches. JASO MA2