One of the guys I ride with did his first oil change on his Softail, he drained the motor with the small plug at the very bottom of the motor. When he told me this I showed him the drain plug on the right side that he should have used. Then he ask me 'why'.
He feels the way he did it is better because it gets more of the old oil out. I don't have a answer for him. We then filed it with new oil and we just got back after about a 50 mile ride and his bike ran great.
So, why is it HD has the oil drain plug in a spot that cant get all the old oil out? There must be a reason.

 

The drain plug in the left (brake side) case half is into the crank case sump. Your buddy didn't get all the old oil out from that drain. A softail has the oil tank above the crankcase sump and that is where most of the oil lives. The rest of the oil is in the cam plate, passages, nooks and crannies of the motor, in the filter and the oil cooler if one is part of the system.

The oil that circulates up to the top end, drains back into the crankcase sump and gets picked up there by the intake side of the oil pump and put back into circulation. Theoretically, there should be very little oil in the crankcase sump. However, with a softail and the oil tank being higher than the oil pump, if the bike sits for any length of time, the oil in the tank will leak past the check valve into the sump. As soon as you start the motor, the oil pump drains the sump and puts that oil back into the system.

There is another problem with opening that case drain plug. It is a tapered pipe plug and it is very easy to over tighten and crack the case; there are members of this forum that have done it.

The only way to get all the dirty oil out of the motor is by using one of the "complete oil change" systems like the Rogue Chopper system; that's the only way.

A word of advice for you and your buddy, follow the service manual and leave the case drain plug alone; you are asking for trouble. If you want to pull all the old oil out, get the Rogue Chopper complete change system.

 

Thanks for the info.
I will pass it along to him, I sure hope he didn't crack his case. Every time we stopped it was oily around that plug he took out. He did say he had a hell of a time getting that plug out. On top of that he had the service manual setting right on the work bench, he never even looked at it.

 

I've done half a million miles on bikes and have never bothered myself about what oil remains in the motor when draining it. I would save your mate the trouble and just do what it says in the service book. Its got me this far without any problems!