Hi everyone, I've been lurking here for a long time (and have learned a lot!), and ran into something I'm trying to figure out.

I have a 99 softail custom that I don't know what it has inside. I bought the bike a while ago, and the owner didn't have any of the specs of what was done to it. It has stock jugs, but S&S super stock heads and super e carb. It definitely has a big cam in it, but I have no idea what. It only has 24000 miles on it, and as far as the owner knew, all the mods were done when it was fairly new (he was second owner, first owner was a friend of his)

Ok, a while ago I started noticing some light oil spatter on the top of the primary and bottom front of the coil cover (like a handful of pin head sized dots). I finally figured out it's coming from the head gasket on the rear head, just in front of the rear head bolt. It's not a leak, or even a weep, just an occasional spatter. When it's running, if I watch it I see small bubbles coming from the head gasket occasionally.

I know I need to tear down and put new gaskets on, that's not a problem, but I've been burning some oil as well. It has never smoked, not on startup (unless I leave the choke on too long, but that's fuel), not under power, decel, nothing. I havn't been keeping track exactly, but I estimate I'm going through a quart every 1000 to 1500 miles. Plugs look good, and the bike runs great, other than it will load up if I spend too much time at parade speed (cam is big and nasty sounding, and likes high rpms).

If I'm not mistaken, the oil returns in the heads are on the back of the head(ive been into twin cams before, but never an evo), on the other side of the head bolt from where my small leak is, but I'm still getting oil spatters. I did a compression test and both cylinders came out at 170 to 175 cold, wot, no oil added. I'm trying to find a leak down tester to diagnose further, but it seems the rings are good. If the guide seals were bad I would think it would puff here and there, but it doesn't. Is it possible that the oil I'm burning is coming from the light head gasket leak?

 

Yes, it could be the case with the oil passage leak at the head gasket, but not the cylinder leak per se. Should be identified with compression test - if it reads normal, both cylinders almost the same, then your cylinder seal is ok, it's just the place where the o-ring goes to seal the oil passage.
Some aftermarket gaskets are not perfect and cause misalignment of the o-ring. I am having exactly this problem now, and I'm not worrying about it till winter. In theory, one can ride like this forever. In practice, I'll change the headgaskets over winter, just to get me peace of mind

 

Last night I turned the rear tire to get the rear cylinder to the top of the compression stroke and watched the head gasket at that spot, I still saw the small bubbles, so the leak must be making it to the cylinder, even if it's very small. I was hoping that I wouldn't see it, thinking it could just be a leak from the oil return to the edge of the gasket. Would a very small leak like that be ok to run on for now? At least for a couple weeks until I have time to tear it down?

 

I would tear it down. The problem is that the hot gasses can eat a channel in the sealing surfaces, theoretically. I mean, you can keep riding it and it will probably be just fine, but I would fix it. And yeah, that could be the source of your oil consumption. Years ago, I had a BHG on a shovelhead. I torqued one side and my friend torqued the other. Our torque specs were not the same. Blew the head gasket, which I could tell by the oil smoke pouring out the exhaust.

Don't know how you guys did it, but the way we torqued shovelhead head bolts was to put a Craftsman 7/16" box end wrench on them and hit the wrench with a 3 lb sledge hammer. No more head gasket problems that way. Ahh, don't try that on an evo.

 

Thanks for the input. That is what I'm concerned about, the sealing surfaces getting channeled out. The thing that sucks is I can't order a gasket set until I get it open. I have no idea what the bore is going to be. It has stock jugs, so I'm assuming it has a stock bore, but will all the other upgrades it has, just not sure. What options are there for stock jugs (what could have been done, boring, ect.)? I'm not familiar enough with evo's to know. Also, would the cometic top end set work since I have S&S heads?