Odd trans oil leak

[william02]

New here, have been restoring a 1973 wombat 125, the bike was originally bought by my fathers uncle and has been passed down over the years to me, though it has been sitting in a garage for the past 10 years.

Right now I am just trying to get the bike into good running condition. I have resealed the tank with red kote, fingers crossed on that, rebuilt the carburetor with a kit from Hodaka parts, and replaced the fuel line, filter and petcocks. Today I tried firing the bike for the first time, after a little fussing with the pilot air screw it idled quite nicely, so I took it around to warm it up, and after about 10 minutes I came to a stop and left it idling in neutral. It choked out after only a few seconds and was not able to be re kicked. I then noticed a pool of transmission oil that had formed in the middle scooped out part of the engine directly below the carb, filling about half the tray.

I cannot figure out where this leak came from, exactly what happened, and why the bike wouldn't fire after that.

I left the bike for about 6 hours, and came back tonight to try again, and it fired first try, was able to heat up and go around, and did not repeat the oil leak.
I only briefly road it tonight, and will give it another go and some more heat cycles tomorrow to continue diagnosing.

Any insight would be greatly appreciated!

[taber hodaka]

Some oils will foam, build a little pressure and spill out the vent. Could it have been a little overfull? New oil mite be in the answer? ----------- Clarence

[william02]

i did replace the oil, that could be it.

[viclioce]

Which oil did you use? Motor oil for cages? MC oil? Gear oil? ATF? Let us know! Victor

[Bullfrog]

It is quite common for an over-filled transmission to eject oil out of the transmission breather vent until it achieves the proper fill level. So, while the experience you just had does not in, and of, itself indicate a larger problem . . . there COULD be other issues. Caution is in order.

1) A failed clutch side crankshaft oil seal could be lightly pressurizing the transmission cavity -- and that will cause continuous oil leakage out of the breather vent. Old seals in old engines commonly fail, so this is also a distinct possibility. Closely monitor that leakage problem for a while.
2) Did I mention old seals in old engines? If the magneto side crankshaft seal fails, your first notice of a problem may be an engine seizure. New seals in old engines are to be highly recommended.

NOTE: Heading out for a ride with truly cold oil can cause a bit of oil to exit the transmission breather vent too. A short pre-ride warm up usually prevents that from happening. In this case only a very small amount of oil usually gets ejected, and the leakage stops when the oil warms up. Just thought I'd mention that so you'd be aware of that possibility.

Ed

[Bullfrog]

PS: Victor's question is a good one too. Some oils are more prone to being ejected out of the breather vent than others. And if there is water (or grease) contamination . . . all bets are off.

Ed
PPS: Modern "purpose built" oils for motorcycle transmissions and wet clutches are highly recommended. (I do NOT recommend the old factory spec. of 30 weight non-detergent motor oil. No.