Oil cap popping open

[mystryman]

I have a prob that I thought I had remedied but has returned. I have a "98 wideglide. The prob is that after I ride for a bit I notice that the oil fill cap has popped open. I also noticed slight leakage from tappet and pushrod seals.
I had thought this was a blowby issue and had recently done a top end rebuild on the engine.( During the teardown found the rings were very worn.) cyls. bored, new pistons and rings, and even earlier had replaced valves, guides and seals in the heads.
Hoping someone could point me in the direction to look next. I'm a little puzzled as what else can cause this.

 

[Spade5]

I am sure this is not the issue but I know a guy that had the wrong dip stick and was overfilling the crankcase. The oil would heat up and expand and in his case would drip aggressively out of the air cleaner.

The other thing that comes to mind is the breathers in the valve cover. I know nothing about the Evo engines but I seem to remember something about one of the gaskets. It seems like a hole was covered up if they were installed backwards or something like that.

Did you install a high volume oil pump? If so it may be creating more pressure than the system can handle.

I know I am not helping you but I wish I could.

 

[mystryman]

It still has the same dipstick and oil pump from when I frist bought the bike. The head breather were blowing oil into the carb before the top end job. Afterwards, breathers still have good airflow and zero oil. best I can figure is some how air pressure still building up in case and tank, not being released well enough. I might be wrong, but my best guess and no ideas to get more release.

 

[TQuentin1]

I had thought this was a blowby issue and had recently done a top end rebuild on the engine.

Hoping someone could point me in the direction to look next. I'm a little puzzled as what else can cause this.

When you did the top end, did you open up the nose cone? What comes to mind is the timing of the breather valve that is driven off the cam. If the timing of that gear is off a tooth (or more!!), you will have less efficient breather action and can be getting some higher back pressure.

Cheers,

TQ

 

[Jack Klarich]

#20, if not timed right will cause the problem you describe

 

[mystryman]

I had thought about the breather gear, but wondered how it could possibly go out of time if the nosecone was never opened up being gear driven and not chain. thinking about opening it up anyway, but before I do, I'm going to order another breather gear. if it still has an oem one, its plastic and if i'm gonna open it up may as well just go ahead and put in a metal one.

 

[Breeze3at]

Were the hoses removed from the oil pump? If they were, it's possible they got reconnected wrong. Are you sure you got the umbrella valves installed correctly? Or the rocker box gasket is not the umbrella model and is blocking them off? Just throwing out what comes to mind.

 

[BUBBIE]

I had thought about the breather gear, but wondered how it could possibly go out of time if the nosecone was never opened up being gear driven and not chain. thinking about opening it up anyway, but before I do, I'm going to order another breather gear. if it still has an oem one, its plastic and if i'm gonna open it up may as well just go ahead and put in a metal one.

I had the trouble with the plastic gears in my 97 FXDS. First jumped time... Problem with oil backing up.
Then when apart, I could see gears were worn out.

The metal was the answer. :s

Also make sure your not running too much oil...

signed....BUBBIE

 

[Jack Klarich]

What oil filter are you using?

 

[mystryman]

None of the oil hoses were touched in all the work done. I double checked the umbrellas and gaskets, I saw in the repair book how easily they could be installed wrong. @Bubbie, that's interesting. I never would expect gears jumping time. I've seen it with chain and belt getting slack from wear. guess that needs to go on list to check out. The filter is a chrome K&N for wideglide, which a bit longer than a standard one.
BTW, Jack, I noticed the bike(trike) on your avatar. Is it an aftermarket rearend? I had just installed a frankenstien on mine and wondered where I could find a body kit to put over it. wondering where you got the body from.