overfilling gearbox oil

[Iahawk]

this discussion comes up fairly frequently...the question of how much oil to put in the gearbox of our air cooled Kymcos. Many people make the mistake of filling it until the oil dribbles out of the fill hole. The actual quantity needed is stamped on the bike...typically 180ml.

A youtuber who has been rebuilding his Agility 125 recently filled the gearbox until it dribbled out, realized his mistake, then drained the oil to measure how much it took to come out the fill hole. 600 ml came out. On a bike that calls for 180ml.

I've never seen someone actually measure the overfilled quantity..but wow, that's a significant difference. When I bought my scoot it was overfilled this way. The excess gets vented into the airbox where it soaks (and ruins) the air filter.

Wanted to share this as I thought it was interesting to see it takes 600 ml to come out the fill hole.

[rjs987]

My Burgman 650 had a way to prevent this in the reduction gearbox and final drive gearbox. It has a drain port, a fill port, and also a level port. There was a spec for how much oil goes in those places but the SM instructions are to fill until the oil dribbled out the level port since that would ensure the exact measure needed. The engine/clutch oil (shared since it is a wet clutch) didn't have a level port to dribble oil out of but did have a sight glass. My AK has only one reservoir for any oil... the engine/clutch oil (also a wet clutch). But the AK has a dipstick and I always ensure oil comes up to about midpoint on that. Any more and I siphon some out, less and I add more.

[Stig / Major Tom]

Yes, Kymco could have made things simpler - and foolproof by just giving us a "Fill-till-it-overflows" hole, and a drain hole as found on other brands.
But, no.

Stig

your post unfortunately reminds me of the Chevy dealer who put 6 Qts in my 4 Qt engine. It was 2 or 3 days before I discovered that, while refilling my wiper fluid...."let's look at the dip-stick while we're in here"
The lengthy & convoluted explanation from the service writer who argued that I was misreading the dip-stick would have been comical - if it hadn't been darn near criminal!
Pretty sure - he, not the kid who did the oil change - lost his job. The kid was trained all Chevy truck six's take 6 Qts.
55 yr old service writer should have known better than to tell an adult that he didn't know how to use a dip-stick. Once I pointed to "6 Qts" on the service receipt.....he got real quiet.

Of course the kid should have double-checked his work by pulling the dip-stick.

[randyo]

I recall years ago, my older brother raced NASCAR mini-stock, with a VW Fastback, had to add additional transmission ventilation, without it, the oil pressure in the transaxle would blow seals, spewing oil on the track to get black flagged