Harley Cam Seal

By Dennis Santopietro

Q: OK, got a question.. Have a 1996 Evo.. Has 42 thou on it.. Runs perfect, But.. It blows the Harley cam seal one after another in less than 100 miles. No damage to cam, no leaks otherwise. ??? Been to 5 H-D dealers.. they have no idea.. Got any ideas?? Started blowing cam seals at 35 thou miles.. went for a few thou miles after first fix down to every 100 miles now.

A: We recommend unloading your top end and doing a thorough inspection inside your cam compartment. There are a few things that can cause the problem you are experiencing.

Cam Bearing: inspect your cam bearing. If the bearing is bad. The cam will not be supported correctly. The cam will slightly tip causing the cam seal to fail. If the bearing looks/feels good; replace it anyway. You are all the way there, and a new bearing is cheap. If any needle bearings are missing from the bearing cage, you have another, more serious, problem.

Cam Cover Bushing: Inspect your cam cover bushing. This supports the outside end of the cam. If the bushing is out of spec, this will also allow the cam shaft to tip, or dip. If the bushing is out of spec, replace your cam cover. We recommend HD only for this replacement part.

Pinion Shaft: Use a dial indicator to measure the run out of your pinion shaft. If the run out measurement is out of spec, it may indicate that the pinion gear is causing excessive movement as it runs against the cam gear. Again, causing the cam to tip, and the seal to leak.

Related Videos:

Cam Chain Tensioner Class

Share tips, start a discussion or ask other students a question. If you have a question for the instructor, please click here.

Make a comment:
characters remaining

5 Responses to “Harley Cam Seal”

  1. vic

    same problem here , put in 3 seals ,still leak?,so what was the problem, ? can't figure it out either

  2. Len

    Just my 2 cents. Is everything up to par on your PCV system? I know guys who loop the venting at the heads without allowing the engine to exhaust the piston back pressure as well as any blowby either to the intake or to the atmosphere. With 42K on it you probably have quite a bit of blowby and it's gonna find a way to get out. Either through your base gaskets of the cam seal

  3. Robert Ross

    This has nothing to do with motorcycles, but is a suggestion for the photo used with your Q & A section of your E-mails. As I look at this photo, it appears that You may have just been "arrested". I suggest that you consider "smile", after all you guy are making a living doing something you love. Let it show. I enjoy you videos, keep up the good work. Bob Ross

  4. jim day

    Harley dealer had no idea!!!!!

  5. dave tuttle

    I've had the best luck with the rubber coated seals , not the steel ones .