I have a 1998 - 1200 Custom Sportster that I keep having problems with,
namely the head gaskets. I bought the bike about 1200 miles ago and since then I havn't been able to make it more than 300 miles before either the front or rear head gasket blows. I have seen two different mechanics that both seam intelligent and fix the issue temporarily. However, I can't make it past 300 miles so something is wrong other than just the gaskets. I have had expensive high performance copper gaskets in, standard H-D ones and multi-part gaskets. All have either blown or leaked within 300 miles.

Recently, something new happened however... The short rear left head bolt actually vibrated all the way loose and fell out the other night while riding down the interstate. While at the time it occurred to me that this is a pain in the *** and I want to get rid of the bike at this point(Being the 5th time dealing with head issues), I realized that the whole time its probably just been the head bolts loosening from riding and eventually blowing the gasket. I'm not exactly sure what the extent of motor work has been from previous owner's, but I can say it's got two new jugs, new head bolt studs, new head bolts, checked w/ machine guy on the head / jug CNC'ing and it all checks out good, possibly upgraded cam and a couple other things added.

That being said, is there anyone that knows how to remedy this problem?
I've heard people say there is a locking type head bolt, others never heard of it.
All the times it has been redone the mechanic assured me he did it correctly with the right pattern and torque spec's according to the book.

I am hoping to find some sort of solution, if anyone has any ideas that would be wonderful. This has been a headache for my dad and I all summer as we have tried to take a few nice rides and been stranded several times.

Thanks for any suggestions in advance!
-- Russ

 

First off, the head bolts should be re tourqed about 300-500 miles after replacement. ( If anyone knows of a way to avoid this, your input would be greatly appreciated. But I found it necessary even tourqing to max. specs.) The next thing to do is check you compression. If there was a lot of motor work done, the compression might be too high . I had this issue and remedied it with rev-dome pistons. The next thing is to measure the studs. write it down and measure again if you blow another one. The studs could be stretching or backing out. If all that checks out, the next thing to do is to have the cylinders and head trued to make sure the mating surfaces are good. I had to do all of the above on my 99 custom. I hope this helps or at least leads you in the right direction.
You could also call Zippers Performance and talk to them about it. They did my work and I am VERY satisfied, and so is my bike.

John

 

Thank you for the information. I will give it a shot, although I may need to re-torque at about 100 miles with the way this thing vibrates.

 

good luck

 

If your having that kind of head gasket issue. I'd see if the head needed to be decked....

 

Baldwin-
Maybe a silly question.... but did you and your father do the tighten, loosen, tighten routine? I only ask as I have heard of guys torquing them to spec and having problems. If any oil, cleaner, etc. is trapped in the head bolt- it'll read good.... only to actually be loose. Just a thought...
Probably why they suggest re-torquing after a run(which blows goats as there is another rocker box gasket).

 

Here's something that just blew my mind and my mechanics. Tonight I decided to tear it down and see what was going on because the short head bolt that I had gotten to replace the one that fell out going down the road did not reach the stud inside the case.

After I tore it down I found that both rear head bolt studs were sheered off somehow. I don't know if the last mechanic I had over torqued them or what but that is a hell of a lot of pressure to sheer two rear stud bolts. I'm going to replace them tomorrow and throw it back together.

I was told by a few people that the head bolt studs in there should never sheer they are very strong metal... but i have pictures to prove it, just can't explain it.

I appreciate the help people thank you. If anyone is curious on seeing the pic maybe I can post it later... Quite crazy how both sheer'd

 

I've seen re-used head bolts shear (not on a Harley though). Replace all of them with new ones - they do stretch when torque'd down and if those weren't new there is no telling how old they are.

 

Well good news for now atleast. Got it all back together and running good.

HeyYou: The studs were brand new about 350 miles ago, so it is odd to me that they sheered. But, the last mechanic that put the Head Screws on must have over-torqued, It's just too odd both rear ones sheered.

I did what a lot of mechanics told me not too also, but it had to be done at this point.
I put a little red loctite on the head screws. I gotta keep them damn things from vibrating out! Mind you this is a last resort before we do big engine overhaul with new pistons or whatever... After blowing 5 gaskets and not making it 300+ miles in between I had to give this a shot.

Thanks for the input everyone.