| Author | Message | ||
     Gordo |
G'day Buellers, got a slight problem.Went for a ride on the weekend, first part tight windies was all good, but on a fast open throttle section on the way home oil filled the catch can then proceeded to gush out all over the place. I was pulling about 4.5 grand at the time (for about 15-20 mins). Would'nt have thought this was bad for the donk! Is this a sign that the rubber umbrella valve in the head(s) is rooted? The oil level was within limits & the rings are still fresh from recent refresh.Any thoughts or ideas? | ||
| Blake |
I doubt it is umbrella valves which allow crankcase to vent into rockerbox then out the breather line, but prevent oil from draining into crankcase. Either oil is over-filled, if so try setting level at lower range on dipstick. or Your engine is suffering from excessive blowby. In that case a compression and leakdown test will tell you where and what is the culprit there, usually ring seal if blowby is an issue. There is one more possibility, your oil became contaminated with water and when the water got to the boiling point the rush of steam blew out a bunch of oil along with. | ||
| Gordo |
G'day Blake, yeah you may be on the money with the oil level as it was just under the upper mark on the dip stick, and from the sound of things that's a bit high. There's no sign of water in the oil, and the rings should still be good but I will check the compression just in case. | ||
| Blake |
Leakdown is more apt to catch any issue with ring seal. | ||
| Gordo |
pardon my ignorance but what do you mean by a leakdown test? | ||
| Gordo |
what's up blake, is my ignorant question beneath your response? well you'll be happy to know that i spoke to a proper harley mechanic about it & he thinks the problem is more likely to be the oil pump not scavenging the sump properly & returning the oil back to the tank, causing too much pressure in the crank. i took the oil tank bung out with the engine running to have a look, & sure enough the return oil was only coming out in irregular spurts. might be time for a pro-flow oil pump. | ||
| Blake |
That is a new reasoning to me. Sounds plausible, but 1998 models supposedly all received the upgraded oil pump to improve scavenging. The reason you only see intermittent spurts at idle is because of the small amount of oil circulating. The pump can only scavenge if there is a minimal build-up of oil. Otherwise it is sucking air, thus the intermittent spurting. | ||
| Blake |
Be sure to check oil level immediately after hot engine shutdown with bike on level surface and standing upright, not on kickstand. When changing oil, put in a total of two quarts of new oil, then run/ride untile engine is hot, check oil level. Add no more than another half quart to bring level up to operating range on dipstick. Adding more than a half quart will overfill the system. A leakdown test... Static pressurization of combustion chamber and measuring time interval for pressure drop or rate of pressure drop. Origin of noise of leakage will point to possible issue. | ||
| Gordo |
yeah i expected the spurting at idle, but it was still happening past 3.5 - 4 grand, although not as much. thanks for the explanation on the leakdown. |
