Seafoam is a good idea too. If you are unsure of the maintenance habits of the old owner. Seafoam will dissolve any gunge on the rings and oil galleries. It does thin the oil a bit but if you change it out after a couple hundred miles it will hold up fine. Harleys don't completely drain anyways so ultimately we are all mixing oils at oil change time unless ya vacuum it out I guess

 

LMFAO! Well said !!!

 

You have the mechanical ability to change out the oil tank and don't know that about 90% of your bikes oil is in that tank? Are you sure you want to continue working on your bike?

 

This thread is ridiculous, the OP can't be for real!

Nobody is this goofy!

Oh, wait . . . tell you what, maybe we CAN Help . . . we can all bottle up our used oil at our next oil changes, ship it to the OP.

 

I'm not worried about the 90% in the tank- I'm worried about the 10% left in the engine...
If you took 90% of the gas out of the tank would you want to weld on it? I guess 10% might be important.

 

What a bunch if silly jackholes! Funny thing, I brought this up to a local indy who was a dealer wrench for 10 years before going on his own and he said... Wait for it... Dump it in a clean container, swap the tank and dump it back it! Oh my! Run it when it all gets back together and change it then. I guess the end result is pretty much the same. If I wasn't swapping the tank I wouldnt be messing with the oil now- I'd wait.
If dumping the same oil back in (oil looks good btw) makes me a freak so be it. It will be in for a couple miles and the pumped out using the scavenge system. I like the idea of using the same oil for 5 minutes better than I like the thought of leaving dirty oil in the engine during an oil change.
BTW- haven't decided what I'll do- seems like a messy pain in the *** to drain then dump back in. I'll probably run some crap oil through to get oil pressure then do the purge.
I think from the posts very few people actually read the posts and understood the situation. If the bike was running right now it would not be a question. Run the purge, swap the tanks and refill with new oil and filter. The bike isn't running and won't be when the tank is swapped. So I had concerns about mixing the oil. (mainly synthetic vs standard)