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Question Posted By: Guest on 3-29-2009
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| Make of Bike: |
h-d |
| Model of Bike |
flh |
| Year of Bike |
1968 |
| Engine Size |
88ci |
| Other info on Bike |
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| What's your question? |
why would motor start puking oil out of crankcase breather?
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| Details: |
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Answers:
- i had this prob with a sporty ,i laid it up over winter and when i went to use it i noticed the oil was low .so i topped up the oil ,got 5 mile down the road and the oil was coming out the crank case breather . i should have thought to myself when i put it away the oil level was ok so why did i need to top it up . lesson learned . By: biggles on: 3-31-2009
- Most engines that are just overbored don't require any increase in the breather valve opening. At 88 cubic inches in a '68, 74 cubic inch engine, you're 20% over the designed-in breather hole size.
With an increased crankcase pressure you're going to get more velocity through the breather screen which produces more oil mist in the camchest. Relieving that hole at the leading and following edge by about an 1/8th of an inch will give you more volume for the oil to be forced through the screen - at a slower velocity. Less oil mist...less oil out through the crankcase breather tube. I've even pulled apart strokers where instead of cutting out a larger case hole they've advanced the breather a notch to start the relief early. Not sure if that philosophy works, or not. No empirical evidence on my part. By: 47Knuckle-Dragger on: 3-31-2009
- Did the same thing 35 years ago. Oil leaks past check valves in pump, ends up in bottom end. You come along months later, check oil, notice it's low and top it off. Start the bike which now has an extra quart or two in it and the pump tries to pump it into a system that's all ready full. It's gotta go somewhere. My 58 Sporty had the screw on oil cap so mine was blown past the valve guides and out the exhaust where it covered the windshield of my buddy's car who was following me. Live & learn.
Kenny By: Guest on: 5-11-2012
Reads: 1976
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