Article By: Corey Barnum
Photos By: The Artist Formerly Known As Craig Harriman
Originally Published In The January 2020 Issue Of Cycle Source Magazine
This month’s tech article illustrates a common problem with most twin cam engines… valve train chatter and oil pressure. This is a quick and inexpensive fix to eliminate the majority of the oiling problems in all Twin Cam motors. We are going to be installing a Baisley LMR-2 oil pressure spring and a precision ground bypass valve. Both of these products are available through Zipper’s Performance. This procedure can be done with the cam plate in or out of the engine. Since we were in the process of upgrading the cams in a customer’s bike, all of our pictures are done with the cam plate out of the motorcycle.
The first thing I do is lay everything out to make sure I have all the pieces I need to do the job.
Here is a picture of the stock oil pressure spring versus the LMR2 spring. As you can, see it’s a stiffer spring. Also look at the edges of the 2 springs. The LMR2 is ground down flat. This will help give you more consistent oil pressure by pressing evenly across the spring.
This is a photo of the oil bypass valve. The Zipper’s version is more precisely ground than the stock version. This helps in sealing and once again gives you a more consistent oil pressure by eliminating oil blow by.
The spring and bypass valve are located on the very bottom left of the cam plate. They are held in the plate by a roll pin. Removal is accomplished with a small punch and hammer. Sometimes a magnet or a pair of pliers will aid in the removal of the bypass valve.
Before I put the Zipper’s bypass valve in, a little assembly lube is put on the valve. As with nearly all new motor parts, assembly lube is necessary to avoid damage during the initial start after installation.
Now just slide the valve down into the hole and make sure that the valve moves freely without any binding throughout the whole chamber.
After verifying that the valve moves freely, start the roll pin in the cam plate. I like to keep the opening of the roll pin on the opposite side of the spring, giving it a solid surface to rest against.
Install the roll pin just to where it slightly extends into the hole. This will aid you when installing the spring.
When installing the spring, use the extending part of the roll pin to hold the spring in place. Finish driving the roll pin in all the way, and check to make sure the spring stays in place.
Here is a photo of what it should look like after valve, spring, and roll pin are installed into the cam plate.
With the ground edge of the spring, increased tension, and the improved bypass valve; this system will create more constant pressure. By doing this little upgrade your oil pressure will increase by about 15%, thus eliminating some if not all of the valve train chatter.