Hey all,

Just picked up a 1986 Softail for what I thought was a good price and during the test ride it had no problems. Just got the bike home after a 30km ride and noticed oil coming from a small hole in the top of the oil tank (5mm diameter). Other than the oil the bike ran awesome.

I blocked the small hole with tape temporarily and ran the bike for another ten minutes.

With the bike running I pulled out the oil dipstick and the air pressure in the tank was massive (big pop sound and the dipstip nearly blew out of my hand). I has it a guess that someone put a vent hole in the top of the oil tank to release the air pressure. Problem being that now oil pukes out the small hole as well.

I can block the hole easy enough but I'm after any ideas about the pressure problem.

Any help appreciated.

 

 

 

Check the crankcase breather hose is not restricted and is venting to ground/external filter and if that's all good start looking at breather valve in cam case maybe , you do get a bit of pressure build up in the tank but not that much for the cap to try blow off
As you said

Once when I had my 95 Softail when the oil got hot it pushed the filler cap up and ran out over the tank...I assumed I had over filled the tank so dropped some oil out and never had a problem again..

has it wet sumped & someone filled oil tank as well , ie if it has been sitting for a while sometimes oil can feed from the tank into the crankcase , you check the oil & see tank is low so top it up , when the engine is started the oil pump scavanges the oil out of crankcase & back to the tank ,because extra oil has been added it has no where to go so must pressureise the tank or leak out somewhere , could that be the case with yours

i still thought it would return some back to the tank , my FXR does it occasionally & returns some out breather & always returns most back to the tank

 

 

I did a 92 Softail recently that was blowing oil in a similar manner. Crankcase vent hose was crimped. Simple fix. Start with the simplest shit first.

Checked the crankcase breather hose a little closer and found that some bright spark lodged a metal rod down it and clamped it off. Had to cut the hose but problem fixed.

Started bike and no pressure issues. I assume the oil blowing out will remedy itself with a good ride?

That will cause it lol , seen the bright spark did a good job of that I would drain the primary oil and replace that two
As there's a good chance some was being pushed pass the eng seal into primary , so she might be a bit over full,
As for what's left in crank case that will clear up real quick with a few blips of the throttle now that she can breath

Will do. Thanks mate.