It is not uncommon to have more crankcase pressure and increased venting when engines are modified. In most cases it is minimal and just enough to be aggravating.
In the case of the 1999 – 2006 Twin Cam 88 Harley Davidson engines this is easily eliminated by installing a Doherty Machine MYSTFREE breather unit.
The kit comes with all parts needed and easy to follow instruction need to replace the factory breather. If you work on your motorcycle and have some hand tools and basic knowledge you should be able to do this at home quite easily.
I started by removing the seat and the battery ground cable.
The instructions say you can raise the gas tank and not have to remove it. I opted to drain and remove it for more room and also to get photos.
Remove the six bolts securing the rocker box cover using a 7/16 box wrench, 3/16 Allen wrench or 6529 Kastar Rocker Box Wrench. Discard the old gasket and then remove the two bolts from the stock breather with a 3/8 socket.
Clean the rocker box.
Install the copper gasket, lower unit, paper gasket, and the top plate. Use a little blue Locktite on bolt threads and torque to 90 Inch LBS.
Install the new rocker box gasket and tighten bolts in sequence shown in the shop manual. Torque to 180-215 Inch LBS
Repeat for other cylinder, re-install gas tank, connect battery ground, install seat, start engine and check for leaks.
There were none so I went for a ride. When I returned there was no misting or fluid out the breather.
I wish every job was this easy and worked as well.
Give the MYSTFREE a try. I am sure you will be happy you did.
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