Changing gear oil

[Zathera]

The manual reccomends that I use SAE 90 transmission fluid(same thing is gear oil, right?) But when I go to stores to look for it, they have NOTHING that says just SAE 90, they have 80w90 and stuff. Does the number next to the 90 mean I shouldn't use that oil? Do I really need oil that just says 90? Another question as well. It also says to replace a washer, do I need a special washer to replace it with?

*This is a 2012 model Agility 50 I'm talking about.

[blue]

80 -90 is ok  and time to time yes you should replace the washer it stops the threads from striping out.
and acts as a seal.

[zombie]

Your local hardware will have either aluminum or copper CRUSH washers. A few cents each.

[REDKYMCO]

This is what i use in both mine and my wife's agility...

http://www.ebay.co.uk/itm/SILKOLENE-BOA-80W-90-HIGH-PERFORMANCE-HYPOID-MOTORCYCLE-GEAR-OIL-API-GL5-/390383084330?pt=UK_Motorcycle_Parts&hash=item5ae4a5232a

Not had to change the washer so far as it has not been crushed by over tighting etc....

[Scooter Russ]

80w-90 weight is ok! The way oil works is the lower number in this case 80w oil all the time. But, with the detergents & chemicals in the oil as the oil warms up it changes molecularly to become a 90w weight.