free website stats program Hello from Idaho and please help. Major oil issue | Harley Davidson Forums

Hello from Idaho and please help. Major oil issue

My 1988 FXST after installing new cam is now having a major oil leak. Heres the weird part, it is out of the crank case vent only while not running. 3-5 ozs, it takes about 5 mins to start leaking. Replaced the check ball and and spring, no luck. HELP
 
Welcome to the forum from Suwannee, Fl.

Welcome to the forum from Suwannee, Fl.
The timing on the breather valve is pretty critical. That would be the first place I'd check to see if it might be off time.
 
Last edited by a moderator:
At full temp about 15psi and an idle, 25 ish while riding

The timing on the breather valve is pretty critical. That would be the first place I'd check to see if it might be off time.
Would that make it blow oil while not running? I was thinking that if that the breather was out of time that it would blow oil out while running. Mine only leaks when shut off
 
Last edited by a moderator:
I agree with above post but are you sure you have the check ball & spring in the right tower?
tourbox
 
I agree with above post but are you sure you have the check ball & spring in the right tower?
tourbox
Yes. The inner one as the outer is the oil pressure relief valve I believe. Ive also thought about the umbrella seals in the rocker box allowing oil to run down into the crackcase after the engine is shut down and not able to return it
 
1988's were crankshaft vented, no breathers in the heads. Unless you have changed to '93 or newer heads? If it leaks while not running, I suspect that oil is not being picked up and returned to the tank by the pump, causing the overfill of the crankcase and leak.
 
You said that you or someone had worked on the engine installing a new cam. How much oil was put back in the engine? If added based on the measurement on the dip stick, how was that done?

See the crankcase vent schematic below. I would suspect the breather timing issue first since that is what was disturbed in replacing the cam. I know it is a bit of a pain, but I would open up the nose cone again and verify all the timing marks align on all the gears (see figure 3-55 on page 190 below). In addition, did you reinstall the spacer on the breather gear (#18 page 188)? And is the breather gear the original plastic one or did you upgrade that?

If you do go back in the nose cone, ensure that you have upgraded the cam shaft inner bearing to the Torrington (#32).

Let us know what you find.

Cheers,

TQ
 

Attachments

  • 97_-_98_Harley_Davidson_FLST-FST_Softail_-_Service_Manual[1] 188.pdf
    162.8 KB · Views: 3
  • 97_-_98_Harley_Davidson_FLST-FST_Softail_-_Service_Manual[1] 190.pdf
    176.6 KB · Views: 4
  • Crankcase vent schematic - Dyna.pdf
    465.1 KB · Views: 3
Last edited:
Back
Top