I usually add about a quart of oil to the engine or slightly more between changes. Now I know where it's going. I changed my primary oil yesterday and it drained out almost a full quart more than what I put in 5000 miles ago. The bike only has about 30,000 miles on it. But it looks like the seal on the crank is bad and letting oil into the primary. The moco shop guy says it's not an uncommon problem. But, since very few people measure how much drains out of the primary the problem goes largely unnoticed. The seal needs to be replaced and the job is not cheap. It's not something I can do. Now I wonder. How many people measure the quantity of fluids that drain out and have the same leak. Mine's a 2009 RK.

 

I have never measured drain quantities, but I have also never had quantity in any location change between servicings. I guess I will start looking at the primary level before draining if the engine ever seems to start using oil. Was unaware of the main seal potential problem.

 

the first indicator is "where'd my oil go?"

this was common problem in about 1992 when poor quality case castings were porous and the oil under pressure was forced through the case into the primary

mike

 

I always dump my engine oil in a container with graduation marks in it, because it is easier or cleaner to dump it into my waste oil container.

 

I had an '86 Heritage with porous cases. Must have been the first one the MoCo ran into. They changed out a bunch of sh*t until they figured out where the oil was going. They were even going to pay my way to Daytona (I lived in Tallahassee at the time) so their techs could take the engine apart and figure it out. About 2 weeks before Daytona clutch inspection cover started to leak. I bought an o-ring to change, but since bike was already on shop mech was going to replace. As soon as he loosened the top bolt, oil started to pour out. He called the MoCo and some whiz kid had the idea to change the cases. Screwed me out of a free trip to Daytona, but the cases fixed the problem.

 

I never measure the primary oil when I drain it but am going to next time because now I am curious. I usually add about 4-8oz of engine oil between changes and attribute the loss to oil that gets spit into the AC.

 

My 97 seal tore and all of my oil filled the primary. The seal (at least in my EVO) was easy to replace with an cheap auto parts seal puller- like the ones to pull the seals in your hubs. All I had to do was remove the primary chain and sprockets and the seal was right there. I would think the twin cam is similar