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P.J.
P.J., Technician
Category: Motorcycle
Satisfied Customers: 740
Experience:  10 years as a mechanic and fabricator in a privately owned, local, custom bike shop.
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1997 Harley EVO. 117,000 mi. Rebuilt the top end @ 58,000

Customer Question

1997 Harley EVO. 117,000 mi. Rebuilt the top end @ 58,000 mi. (about 8 yrs ago). During operation, oil is being drawn out of the primary and into the engine crankcase and over filling the oil tank. Replaced the sprocket shaft seal and race. Also, removed the bolts in the primary that hold the stater wire, sealed them with silicone and put locktight on the bolts. Problem still occurs. NO one I've talked to has ever heard of this problem! Bike starts and runs great. Doesn't run hot. Any help would be greatly appreciated! Thanks, Gregg
Submitted: 1 year ago.
Category: Motorcycle
Expert:  Steve replied 1 year ago.

which way is the sprocket shaft seal installed? lips facing IN or OUT?

Steve

Customer: replied 1 year ago.
Changed the seal several times, faced lips both ways.
Expert:  Steve replied 1 year ago.

it should be installed lip out, with green loctite sleeve retainer around the OD and "assembly lube" around the ID where is contacts the shaft.

the issue with the cast-in steel bearing race seat was resolved in the early 1990's. that is not your problem. sealing the stator screws is always a good idea but seldom the problem, in these cases.
the only other possible source of a leak is a crack in the crankcase, inboard of the primary O-ring seal. that, however, is not a common problem with EVO Softails. that doesn't mean it's not your problem, only that it would be unusual and typically indicates a misalignment of the engine/primary/transmission during assembly.

let me know if you need more help.

Steve

Customer: replied 1 year ago.
Would a misalignment of the engine/primary/transmission occur during the rebuild of the top end? That was years ago and this problem just popped up several months ago. No other engine worked has been done since the rebuild and this bike has never leaked or smoked. Would anything else cause a misalignment? Bottoming out in a pothole for example?
Expert:  Steve replied 1 year ago.

no, a top end rebuild does not require removal or realignment of the primary chaincase, engine or transmission.

there are any number of reasons for what can cause a failure resulting the type leakage you have. the most common is failure to maintain the bike per the factory maintenance schedule which requires re-torquing of critical fasteners at specific maintenance intervals. engine, primary and transmission mounting bolts fall into this category. this is usually only a problem if people quit taking their bike into a shop for maintenance and start to just perform home oil changes. I don't know if this is your issue. I have no idea how you maintained the bike, or didn't maintain the bike. I am just trying to give you all the information I have.

Steve

Customer: replied 1 year ago.
I appreciate your help. You've already given me more info. then anyone else I've talked to. THANKS! I get the bike serviced every 5,000 miles. Not sure if re-torqueing has been part of the service or just oil, filters, tires, cables, brakes, etc. I don't do any of the work myself. If our mechanic finds anything wrong other then the regular service items, he either calls me or just goes ahead and takes care of it, and lets me know. If, after the re-torqueing sequence is complete, the problem still exists, what would you recommend as the next logical step?
Expert:  Steve replied 1 year ago.

you have a leak.

you need to find it and:

- repair it, if it is repairable.

- replace it, if it isn't.

Steve

Customer: replied 1 year ago.
I know there's a leak. Finding it is the problem. That reply didn't help!!
Expert:  P.J. replied 1 year ago.

How much oil is pulled out of your primary?

In other words, when you fill your primary it should take somewhere between 32 and 42 ounces. Have you measured the amount of fluid, if any, that remains in the primary after this problem occurs.

Thanks, P.J.

Customer: replied 1 year ago.
Have to check with our mechanic, not sure if he has measured that or not. All I know is after an oil change, we'll ride between 70 and 100 miles and the oil level in the tank is up to the bottom of the filler tube of the tank and the oil in the primary is low. I'll try to find out if he has measured the amount and let you know. Bike runs great, no leaks, no smoke. Just a full oil tank.
Customer: replied 1 year ago.
Haven't been checking how much oil is left in the primary, just made a couple of repairs and tried again. Does the amount of oil left in the primary tell you anything? Will it just stop after a certain amount is drawn out of the primary? Could I then just drain some of the oil out of the tank to it's required level and go?
Expert:  P.J. replied 1 year ago.

What types of repairs did you make?

I'm wondering what makes you think your primary oil level is low. Are you visually looking at it through the derby cover? Is the oil level below the bottom of the clutch basket?

To get an idea of what may be going on we need to determine what the primary oil level is doing. Get a reference level on the clutch basket (which is where the top of the oil level should be) and then ride it and check it again. Do this a few times and tell me exactly what you find.

I'll tell you what I'm thinking. Just like everyone you've spoken with I've never seen or heard of the primary oil going anywhere but on the ground, from a leak. There is no point when there is a vacuum created in the crankcase to cause the primary to be drawn into the engine. I just can't see that being a possibility. What I feel is happening is your engine oil level is rising due to gasoline overflowing through the carburetor and flowing into the engine. This is extremely common and, in my opinion, is the source of your "extra oil". If it is gasoline then your oil should smell like it. If it does then this is very bad for your engine and I wouldn't run it that way.

If you carefully set that primary oil level at a known level and it goes away then I'd look for a leak. The seal around the front pulley is the most common leak that develops. There are plenty of other spots too and they won't always cause oil to drip onto the ground. You should see road grime stuck to the leaking area though. The cleaner your bike is the easier it is to find the leak. If it is filthy underneath then it can be difficult to pinpoint.

I hope this helps. Please let me know what you find and if I can be of further assistance. Thanks, P.J.

Customer: replied 1 year ago.
Where would the gas come, how would it get there, and how would we fix it? You've been really helpful, not to mention patient. I'll continue to stay in touch till we get it figured out. Thanks again!! Gregg
Expert:  P.J. replied 1 year ago.

The gas gets into the oil by way of the intake and cylinders.

Gas can leak past the needle valve in the carburetor and, when the bike is leaned on the kickstand, the gas passes into the intake, down onto the piston, and then passes down the cylinder walls into the sump of the crankcase. Once it is in the sump the oil pump picks it up and returns it to the oil tank. It is (used to be) a very common problem.

Thanks, P.J.

Customer: replied 1 year ago.
Isn't there an overflow mechanism to prevent this from happening? If gas is leaking down through the cylinders and into the sump in the crankcase, what's the fix? Rebuild the carbs or just replace the needle valves? The carbs are original and have never been touched........... Just pulled the dipstick and there is an odor of gas. This is as close as I've been to a cure!! You've been very helpful!! I'll let you know how it turns out. Gregg
Expert:  P.J. replied 1 year ago.

There isn't an overflow mechanism. The fuel flows into the throat of the carburetor via the main jet and has to go somewhere. When the bike is on the kickstand it goes into the cylinders.

Turning off the petcock can limit the fuel flowing through a needle valve when not running.

Thanks, P.J.

Customer: replied 1 year ago.
I should start by having the carbs rebuilt?
Expert:  P.J. replied 1 year ago.

The carb may not need completely rebuilt but the float and needle obviously need attention if it is letting fuel leak by. The float may be out of adjustment or the needle valve not seating properly.

Thanks, P.J.