Base Gasket Bubble
I think after mine is hot it stops bubbling.
If it's your Main Bike, Fix It.
I will keep an eye on the situation for now but may take it down to the local indy for some piece of mind. This along with some oil dripping form the air cleaner makes me wonder if I may have a PVC issue as well. Crank case pressures may be part of the problem.
Bike possibly wet sumped over the winter and filled the crankcases with oil.
So when you started it up, it had a guts full of oil and developed high crankcase pressure for a while until the breather and oil pump could clear the excess oil and air pressure out of the cases.
The higher than normal crankcase pressure combined with the higher than normal oil level in the cases could have caused your bubbles.
Ride it a few times and see if the bubbling goes away before you tear into the engin.
The MoCo design leaves a bit to be desired when it comes to the oil return from the heads. Basically you have a hole in the head, that matches up with a hole in the jug, that matches up with a hole in the case. Only thing preventing the oil from leaking at those points is a gasket. Rather than install a hollow dowel pin in the jug that mates up with the hole in the case, which would prevent the oil from pooling inside the gasket, The MoCo put their money on the base gasket material. It was a good bet for HD, as most new bikes didn't leak until after the 12 month warranty expired. Not so good a bet for the owners, who had to deal with the issues.
IIRC, the stealerships get around 6 hours labor to swap out base gaskets. Plus parts. An average home wrench, can probably get it done in a day or a weekend, depending on what other issues 'come up'. Last time I bought a rocker box gasket set it was around $50 from their parts department. I have no idea what the rest of them would cost.
Personally, I wouldn't get it fixed until some other problems surfaces, or you were looking to tweak performance.
Last edited by Hackd; Mar 16, 2014 at 04:48 AM.
The Best of Harley-Davidson for Lifelong Riders
Imagine the HORROR when I started her up for the first time, and , sure enough, she was "bubbling" at the base gaskets....... After I broke in the new cylinders and rings etc.. It stopped......
After a few rides the bubbling stopped and now the weeping is minimal. My plan is to just ride for now and see what it looks like at the end of riding season. May consider opening her up this winter.
Another tech told me to shoot some WD 40 on it periodically in the winter to keep the gaskets moist. This will help out in the spring.
Appreciate the replies!








