Just a guess, but I'd think the second ring on the rear cylinder maybe upside down? You can get one of those cheap mini cameras that plug into a cell phone or laptop, that enables you to see the top of the piston through the spark plug hole. If the valve reliefs have oil sitting in them, it's getting past the rings, or intake valve stem seal.

 

JMHO but that is the next step; no need for a leak down test when you have hard evidence of poor ring seal. As has been suggested, could be ring installed upside down since the top end job is fresh, the drop in compression and the other cylinder hodling compression.

Let us know what you find.

 

It would be very easy to pull the exhaust first and take a look into the exhaust port and see if oil is coming in from the guides.. You can pull the intake as well to check those guides... Take pics and post up.. That's a lot of oil... How did you break in the rings and how many miles since the rebuild?
Also what year, What cam and Any head work..

 

Thanks djl, I'm going to pull down the rear cylinder and have a look.

It's funny because I got the machine shop to gap and install the rings for me, so this very thing would not happen!!

I'm ordering a new set of rings for the rear cylinder now.... Should I redo the front piston rings as well? Or leave that cylinder alone?

Thanks for your advice.

 

Thanks, that is a good idea. 👍

 

Hey hotrod, around 50 miles since the build.
2002 fatboy- Wiseco 95" pistons, CR575 cams, a set of stock cc'd 2009 heads, 10-1 comp.

I'll pull the exhaust off and take some pics as soon as I get the bike back on the lift.

Do you think I should redo both cylinders - fresh set of rings? I have to buy the full gasket set anyways?

Thanks for your advice

 

Don't ask question to issues your not sure of yet.. First figure out where the oil is coming from then go from there... What was your break-in procedure? Also were the heads rebuilt before you put them on? Or did you just buy someone's take offs and throw them on...

 

ok, thanks. Yes the heads were faced / cc'ed and new valve stem seals

Break in procedure was 3 heat cycles. Followed by a nice easy ride to let the engine reach full temp, then 25 mile ride just like I would normally ride except keeping it under 4000rpm and plenty of deceleration / engine breaking to seat the rings.

Cheers

 

I'm starting to believe that more that more than 30 miles are necessary to seat the rings.. This my last build I did 400 miles under 3000 Rpm and I got on it once and puked a bit of oil out the breather so I took it easy for another 400 and it now seems the rings are fully seated... Some say more miles some say less.. I'm starting to believe more for longevity..

 

ok thanks, so you're saying do another 100 miles and the see what it's doing?

Cheers