Changing transmission oil on my scooter

It is normally recommended that scooter transmission oil be changed at least once a year. Once I hit 6000km - probably more then a typical year's worth of riding - and especially after that long ride to Duluth, it seemed like transmission oil change for my Baron was due.

There are three types of oil you can find in motorcycle and auto stores, besides the cleaning/penetrating types. These are various types of engine, automatic transmission fluid (ATF) and gear oil. While our scoots have "automatic" transmission, the V-belt transmission works quite different from car's AT and what I believe should be used for scooters is the gear oil. This is the stuff that goes into manual transmission boxes and perhaps other machinery. Gear oil is standardized similarly to engine oil, by a range of viscosity. I dug online a little and found suggestions to use 75 to 90 W oils for scooter transmission. This is exactly what I'll be going for.

It is a good time to remind you that I am not in any way offering a professional advice on these pages.

What I found in AutoZone was a cheep and very convenient bottle of 75-90W, exactly what I needed. It cost about $6. The most expensive one from Mobile-1 (with a larger range, up to something like 140W), was about 15$. The bottle is so big it will last a lifetime, I just wanted to use mineral oil. All of these bottles had convenient funnel tip which helps to squirt the oil into the transmission box and set the level correctly.

So there you go - it's meet-the-bottle moment (these are full-resolution images):



Main points about it are
-It is gear oil
-It is rated 75W-90 (wider range is OK)
-It has a funnel tip

The oil is drained from a drain plug on the bottom of the V-belt box. There's really a small amout of it. I drained mine into a glass jar. This fill screw is on the side of the transmission box. Here's a pic:


The screws are M6 and so they take a 10mm wrench or hex sockets.

Notice aluminum gaskets on each of these screws. They get smashed a little by the screws and hold the seal to keep the oil in. It is a good practice to replace these sorts of things, but I just put mine back in.

Draining was easy. I drove it around to warm up the oil a little. Then I stalled the scoot (which means turn off the ignition), put it on a center stand and undone the drain screw. Some dark and really thick oil come out. It really looked like it was long due! (Undo the level screw to let the oil flow out easier.) Since it was so viscous, I had to wait upward of 10 minutes as it just kept oozing out. Then I cleaned the drain screw and its gasket in this very stuff (which in fact becomes a great penetrating oil) and put them back in.

Filling is easy with the funnel-tip bottle. The bottle is flexible, and you just squeeze the bottle to force the stuff in and then let whatever is in excess to flow out. I repeated this to make sure the oil filled all the cavities. Once again, it takes a rather long time for it to drip out. The scoot is supposed to be horizontal for this procedure, so I just did my best to kinda lift the front wheel up a little. I am not sure if this was at all necessary. Then I put the level screw with its gasket back in.

The seals. Since there's no level meter (the level is simply at the position of the fill screw), my biggest worry was that it will leak some oil without me noticing. It got the screws tight with a ratchet, but not crazy-tight as to not to crash the gaskets or break the threads. Then I rode a little and parked the scooter overnight with a piece of paper under this area. Nothing came out so I assume I did this correctly. Still, there was a little grime on the level screw later on when I did this picture.

The ride. The scooter did seam a little quieter and smoother, but hey maybe it's just in my head. I have my idle set too low so the scoot sometimes stalls at intersections. It does seem to happen less often now after the change.