Was changing out the clutch cable for ape hanger bars and found my transmission oil looked like a milkshake. How the hell does water get in there? I was told it might be the vent hose but need some experience so it doesn't happen again

 

Vent hose is the culprit. Or more that the vent allows humidity from outside to enter the tranny. It doesn't get hot enough to "boil" off the moisture so it builds up over time.

It is possible that water gets in from a little too zealous use of a water hose, too.

How often are you changing the juice, both mileage and time-wise?

 

That is the questions that popped into my mind too. I wash mine with water maybe once per fluid change and have never seen any water in my trans but I'm very conservative with how much water gets sprayed on the bike, especially in and around the vent tubes. If you change it every 5k and don't wash it with a hose, there is a problem.

 

Riding in heavy rains, using a pressure washer to wash you bike, and living in a humid climit and extended service intrevals can be the causes. I think it's best to just change the trans oil when changing the engine oil. But, there are plenty of people out there that skip and only change the trans and primary every other engine oil change.

 

I recently purchased this bike from an estate sale so I have no idea how it was washed/serviced. It has 35,000 miles and I'm starting my own service schedule. I've been told to reroute the vent hose.

 

Water could be getting into the clutch cable adjuster and finding its way into the gearbox

 

if you don't know the history of the bike I would just change it and keep an eye on it , maybe change it again in 500 miles or so to get any left over out ,surprised no one mentioned the radiator , LOL

 

The vent hose has been that way for decades. I wouldn't change it's routing. Just change the tranny fluid once a year, or between 10,000 and 15,000 miles.

 

I just changed all the fluids and the trans is getting the oil changed again after two hundred miles. As soon as funds allow, I'll do a more through service.

 

Basically, when a bike is bought used it is best to change all fluids unless service records are available and trust worthy. Just because paperwork exist it does not mean it happened. Seems like you are on the right track.