Search all blog posts here.

Search This Blog


Tuesday, April 5, 2011

Bigtwin Oil Pump Check Ball

Bigtwin Harley's will sump a bit a especially after sitting a bit, but this much is way too much. The check valve in the oil pump is a ball and spring, item 11 and 12 on this diagram. I read about this fix. It looked good, but I didn't want to take off the pump. If replacing the ball and spring doesn't fix it, I will try lapping the seat. Clamp off the gravity feed. Remove the inside cap. Here's the cap and spring out. You would think that a steel ball in an aluminum hosing would come out easily with a magnet on a stick, but that didn't work. The oil around the ball wouldn't let the ball out that easy. I has to use the mighty vac to get it out. It also helped to get any crud that may be in there hanging the valve open. The ball had a nice wear mark from the seat so hopefully the new ball and spring will fix the problem.


  1. Check this post, too.

  2. Thanks I needed that - Same problem - and this engine was suppose to be rebuilt ! Ha !

  3. This comment has been removed by a blog administrator.