Does the oil pump have a check valve?
From 1968 to 1999 the oil pumps are all pretty much the same in respect to the check valve. The check valve is used to keep the oil in the oil tank when the engine isn’t running. When the engine is running there is oil pressure that opens the check valve and allows the oil to flow through the engine.
When was the check valve added to the oil pump?
How big is the check ball on an Evo pushrod?
The check ball measures .375″ (3/8″ Bearing). An EVO pushrod has round ball end that can be used as a lapping tool. Place the pump body in a vice with the top up. Note the vice has soft jaws and the oil pump body is protected further with a soft towel. Only tighten the vice enough to hold the part, do not damage the pump surfaces.
Where does the check ball go in an oil pump?
Red arrow number 2 indicates where the check ball is installed into the pump body. It has a spring that presses the ball onto the seat, just above arrow number 1. When the oil is pressurized it lifts the ball off the seat and flows to the engine. This is looking down into the oil pump body where the check ball goes.
Is there a problem with my Evo oiling?
The bike has been barely ridden, it’s a ’99 with about 12,000 miles on the ticker. Any help would be greatly appreciated. Welcome to the forum. There could be several issues and yes the key being sheared, but it could also be that the check valve (ball) is not releasing and this would cause no oil circulation.
From 1968 to 1999 the oil pumps are all pretty much the same in respect to the check valve. The check valve is used to keep the oil in the oil tank when the engine isn’t running. When the engine is running there is oil pressure that opens the check valve and allows the oil to flow through the engine.
The check ball measures .375″ (3/8″ Bearing). An EVO pushrod has round ball end that can be used as a lapping tool. Place the pump body in a vice with the top up. Note the vice has soft jaws and the oil pump body is protected further with a soft towel. Only tighten the vice enough to hold the part, do not damage the pump surfaces.
Red arrow number 2 indicates where the check ball is installed into the pump body. It has a spring that presses the ball onto the seat, just above arrow number 1. When the oil is pressurized it lifts the ball off the seat and flows to the engine. This is looking down into the oil pump body where the check ball goes.
What is the check valve on a bigtwin oil pump?
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.