Base gasket leaking?

[EasyRider84]

Bump, ASWRACING whatcha think?

[EasyRider84]

Anybody have any more input?

[BrokeRecord]

That was alot of talk about how to fix a lil gasket! LOL

[aswracing]

Originally Posted by EasyRider84

Maybe I'm confused about head decking as well. How do we know these heads were decked?

The easiest way to know that is to just measure them. If they're 3.690, they're stock height.

I was just talking about having them resurfaced to make sure they are flat. I'm in no way looking to up the performance of the bike. I'm just looking to get it back on the road and running for as cheap as possible.

Well, "resurfaced" is just another word for "decked" to me, although it perhaps implies less material removed. From us it costs the same amount whether we deck them .001 or .100, but that may or may not be true for other shops. In any event, they need to be decked/resurfaced enough to remove any damage and get them flat again.

How much will have to be removed to clean them up? What is you chamber size now and what will it be once you do that to them? These are questions you need to answer, in order to answer the piston question.

I know nobody wants to hear that. In my personal situation, it's either get it back running for cheap or it may sit for another 6 months. I got out of the military and I'm a student, so the funds just aren't there right now. I don't see why I'd NEED a valve job.

Well I don't know if you need one or not, all I can say is that I'd sure look at it while I had the heads off. Because if you do need a valve job, it may change the final answer on the pistons.

Here's a quick experiment you can do. Pour a thin solvent into each port, intake and exhaust, on each head, and see if any leaks out past the valves into the chamber. Brake cleaner works well, gasoline will do in a pinch.

If you find that the heads do need a valve job, I'm just saying it could change what you want to do on the rest of the project. So it's best to gather this kind of information up front.

Ditto your current chamber size. You need an accurate measurement, which it didn't sound to me like you have. Regardless of how you put it back together, you want to know what you've got, right?

The bike was still running great when I took the top end apart. I'm new to all the motor stuff though. I only took it apart thinking I needed a new base gasket because it had developed a leak at the base, no oil though, just air.

But didn't you find a damaged cylinder and head when you took it apart? And possibly a pulled up stud? And isn't there some question about the chamber size and CR and potential for detonation for having caused these things? Or did I misunderstand?

If that's an accurate characterization of the situation, all I'm saying is that you really need to understand what you're putting back together, to keep a failure like that from happening again.

Well, that process starts with making measurements and evaluating parts. What's it going to take to get the heads back into shape? .001 off the deck or .050? Are they going to need a valve job? What size will the chambers be when they're done? What compression ratio will that give you with flat tops? Will you need dished pistons?

Those are all open questions at this point, near as I can tell. I'm just suggesting that you do this evaluation before you make any decisions.

As far as I can tell, my flat top pistons are in good shape. Unless I need to go to reverse dome, I should be fine with those. My pistons say STD 4 on top of them. Is that factory?

Yes, that means standard bore. Have the pistons been removed and inspected? Has the current compression ratio been verified?

If they're in good shape, and the heads, after repair, are still going to give you a workable compression ratio, then sure, save a few bucks and reuse them.

But if the chambers are going to come out to 50cc by the time you fix the heads, then no, you'd be foolish to put it back together with those pistons.

Then again, if the heads need a valve job anyway, the process of doing a valve job can be used to your advantage to make the chambers bigger and possibly make the flat tops usable.

See what I'm getting at? The repairs needed to the heads and the piston decision are intertwined.

I appreciate any advice, and have full respect for your opinion based on your reputation on the boards. I'd love to send the heads to you, but I imagine shipping isn't cheap. I assume that if I sent them, I probably wouldn't be able to afford the work needed. I don't really trust any of the indy shops I've been to in the local area. I went to see a motor guy. He seemed to really know his stuff, and had a pan, shove, and knuckle he was working on for out of state customers. Unfortunately, he didn't really have any Sportster experience and couldn't even identify if the heads were 883 or 1200. I've since figured out they are 883, but I don't know if the guy is right for a Sportster motor. Thanks for any input.

Well, I'm not concerned about whether you send them to me or not, I'm just saying that a full evaluation needs to be done. You need to understand the condition of the heads, and the chamber sizes, and more importantly, the chamber sizes after they're reconditioned enough to be used again, and decide if they're going to, at that point, be compatible with flat tops or if they need dished pistons.

[Gcram399]

Originally Posted by EasyRider84

Anybody have any more input?

I agree with Aaron. You need to know exactly what work was done to the heads to be able to give you proper advice for your next step if you hope to end up with an engine that will operate properly. Just too many variables to take for granted when trying to figure out what kind of compression ratio you'll end up with. For someone to give you advice without knowing, wouldn't be in your best interest.
I do appologize if this isn't what you wanted to hear, but it is an important factor.

[EasyRider84]

Thanks for all the input guys. I hear what you're saying, it's just not what I wanted to hear. That's the way it goes though right? I'll probably have to hold off for now. Aaron, I appreciate the valuable advice. I have no clue what I'm looking at for price on the work, I know it depends what I need. Are we talking 750$ ballpark? Hard to justify with what I paid for the bike, but I guess you get what you pay for. Aaron, pm me if you don't mind. I'd like to get an idea of what I'm looking at so that I can start putting the funds together. As far as I know there isn't anyone in the Charlotte area that really messes with Sportsters, so I'd most likely be looking at sending them to you. I just wanna get the knees in the breeze again.

[EasyRider84]

Whoa, I must be a bit high there on the head work if a new set is in that price range.

[aswracing]

It shouldn't cost anywhere near that much.

We charge $25 each head to deck them, and $22.50 each to CC them. If I understand everything correctly, those are the only things we know for sure you need done to the heads.

A valve job, if you need it, is $50 per head. Did you try the pouring-gas-into-the-ports test?

Chamber resizing is $75 per head, but that includes the CC'ing, so effectively $52.50 per head. Again, we may or may not need to.

Add to these numbers a few bucks for a set of valve stem seals.

So worst case, $150 per head plus parts & shipping. More than likely it would come in less. We really have to see the heads and make some measurements before we can say, though.

Not sure what you're planning for the cyls and pistons but we can help there, too. If you want to send them along we can evaluate them and advise you.

You can see all our machine shop service prices here.

[EasyRider84]

Yeah, I don't know why I was thinking it would cost so much. I didn't base that on anything, just a wild guess. Sounds great Aaron. Hopefully I can do this soon. What's your average turn around time for something like this? I'm definitely gonna need at least 1 new cylinder, and I'll probably send my pistons along as well just to see what you think.

[EasyRider84]

Ready to get some work done. What's the best way to ship heads, cylinders, and pistons?