I'm in the middle of a top end rebuild and when I was taking the front cylinder apart one of the cylinder studs came out with the head bolt. No big deal, I ordered a new stud but when I went to put a head bolt on it it seized almost immediately. Felt like cross-threading, but is not. I was able to use a double nut to put it in place, so I figured the stud was out of spec. I ordered some used ones and figured if they came out of a running bike they'd definitely work, but I'm having the same problem. Have tried both the old head bolts and the replacements I got and have the same problem. So... is this normal? Is it a way of making the bolts bite into the studs and stay in place without loctite or am I missing something? Don't want to get my engine put back together and then not be able to get one bolt properly tightened because of bad threading.

 

IIRC … the studs are made with an interference fit … and I think to install them it is recommended to use one of the head bolts with a small ball bearing inside so the stud doesn't lock in the head bolt ...

 

FWIW I am not exactly sure what the OP question/ concern is.

Just to add...if the stud came out with the head bolt, just
perhaps the stud "pulled out" the threads too. Perhaps
this lack of threads is the resistance the OP is experiencing?
Can you see into the studs mounting area?

Anyway, good luck, there are lots of experienced XL mechanics on this forum.

 

Hey, thank you both! I think it's honestly just the wrong part. My diagram from HD lists the part number as 16832-86C, which is what I've ordered, but when I compare with the old stud they seem about a quarter inch longer and the threads seem just a hair thicker. Instead of coming to a sharp point on the outer edge of the thread the new ones have a tiny flat spot.

The original explanation of the problem was a little bit of a mess. Basically, the head bolt seizes on the stud within about a quarter turn. It feels similar to cross threading but more severe.

Threading in the mounting area is fine, luckily.

I think I've found some that are going to work... hopefully third time's a charm.

 

Well, I'm thoroughly confused, but if the OP has it under control, I'll relax a little.