89 Sporty Puking Oil

[cowboykp]

89 Sporster runs fine when it first starts, but as soon as it gets hot the oil pumps out of the breather hose. It will keep pumping until the tank is empty. I can see that the oil is returning back into the tank, but for some reason, when it gets hot, it dumps out the hose. Any suggestions?

[andyxlh]

Hello mate
the pump has 4 external connections, the front two run to and from the oil filter fitting. How are these hoses? I can't remember which is the feed and which the return, I think the lower one is the feed. The return hose could be blocked?
The breather has a check valve in it inside the cam cover - a simple rubber butterfly, but if that has gone I would think that would not cause an issue. When left standing for a long time oil can seep through the pump and cause a wet sump which will cause the problem you mention, but that usually occurs on start up and only when it has been standing for a while.
I don't have a definitive answer, but i would:
check the condition of the hoses - if they are original they could easily be blocked. replace them as they are cheap.
if no joy:
pull the oil pump and filter mount. the hoses from the pump to the filter are external on these early evos. both can be removed without taking off the cam cover.
Check the OEM workshop manual - I don't have mine with me, but it has an excellent fold out diagram showing the route of the oil through the engine. trace the path and you might find the fault.
There is a non return valve system in the oil filter with a check ball, but I have never had to play with it - perhaps this could be faulty - you can check when you take the filter mount off.
Best of luck
Andy
Sydney
'89xlh
'96flhr