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Discussion Starter · #1 ·
My '87 has a newly rebuilt motor, with Thunderstorm heads. These heads don't have a vent in them and the motor breaths lower down on the case. Here's where it gets interesting...

When I got it a few months ago, it had decent oil pressure. About 7 at idle. Now, at startup, there is 10 lbs of oil pressure. As it warms up it drops to zero, and the lifters start getting noisy. It has the new all for one Harley oil. 20/50 I think. They told me they don't sell the sportster only oil anymore.

Would this be a problem of a bad oil pump?

Improper breathing of the motor? Which seems unlikely. If it was building up too much pressure, wouldn't it be puking oil?

Anything else I should look into? It's been sitting for a month cause I have been so insanely busy, and it's killing me not being able to ride.

Any help appreciated!
 

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>>My '87 has a newly rebuilt motor, with Thunderstorm heads. These heads don't have a vent in them and the motor breaths lower down on the case.

Just my $.02. I rebuilt my 2000 Sporty with Thunderstorm heads and I know they definitely had a vent and breathed through the heads. Not sure if they made different year T-Storm heads... but I doubt it.

Thanks,
Jim
 

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Well I do know everyone has switched over to using 20/50 in everything now. Amsoil synthetic is now 20/50 for everything too so they are bullshittin ya there.

Are you getting oil pressure at higher RPMs? My Evo big twin motor has about 10 on cold start up and it drops to 0 at warm idle too. Alot of motors will do that. The pumps dont produce much pressure.
 

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Discussion Starter · #4 ·
Not sure Jim. There definitely is no vent.

If I'm lucky, I can get 2 at higher rpms. This is my first Harley, and I don't want to fuck it up. I think the manual says a stocker should have 7 at idle. It's just that dropping to zero scares me.
 

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Have you changed the oil filter recently? For no reason should you run a Twin Cam 10 micron oil filter on a sporty (or Evo for that matter) It's too restrictive for the amount of oil pressure the pump makes and will definitley cause problems. Just a thought.
 

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Discussion Starter · #6 ·
I should clarify, there's no breather in the rocker cover. Not sure about the head itself.

Would the filter have a number on it? How would I know what it is? I changed the oil and filter right when I got it. It's one of those Harley chrome jobs. I told them for an '87 Sporty, but maybe they gave me the wrong one. Of course when I got a new tire, they told me it was the oldest one they had in the shop. :rolleyes:
 

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>>I should clarify, there's no breather in the rocker cover. Not sure about the head itself.

Ok, yes. They breathe through the heads- the 2 bolts that usually hold the carb to the heads are hollow and the factory vents it right back into the carb through those bolts. You can get or make a kit to vent externally by just connecting to those hollow bolts and routing it elsewhere.

Also, not to knock the JJ... but when I built my Sporty, this site was invaluable (especially the archives): http://www.sportster.org/xl-list/

I never checked the oil pressure on mine. I had a stock oil pressure switch and idiot light on mine. After oil changes, if the light turned off, that was good enough for me. The valve train was a little loud and rackety... but that's just the way it was... ran great that way for 26K miles (and then I sold it).

Thanks,
Jim
 

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Discussion Starter · #8 ·
The bolts that are in it aren't hollow. So I guess I'll have to get some of the hollow ones and try that. The other thing I thought of was putting some AN fittings in the rocker covers and running it down to a catch can.

I've poked around that site, but I can't stand "lists" in this day and age. But I will try it out. Thanks.
 
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