| Author | Message | ||
     Titusand |
My Blast: 2004, totally stock, about 4000 miles. It got loud all of a sudden and when I looked I found that at the exhaust pipe at the head, the chrome "clamp" ring had fallen down the pipe, and remaining at the head was only one bolt, not two. Furthermore, if you look at the 2004 parts catalog, it does NOT describe these bolts. It does describe the nuts, but not the bolts. Questions: how are these bolts held in place? How do I replace one? Does any one know the exact description of these bolts? | ||
| Gearheaderiko |
part #16715-83 Basically the same as a Chevy manifold carb stud. 5/16" stud. Coarse thread on one end, fine thread on the other (SAE-USS). I dont have the exact length. Its used on many Harley's since 1983 and probably many others too! The studs are screwed in place. Some studs are "deformed" (I cant remember the word for it) at the inserted end that holds it in place. However just tightening the nut also holds it in place. A replacement should thread right in. If the stud is broken off in the head, it'll have to be drilled or otherwise* removed. WARNING: DO NOT USE an "easy-out" to remove the stud. It will break off in the head and you will be forced to buy a new head or take the head off the bike and have it professionally removed. Dont kid yourself. IT WILL HAPPEN TO YOU. *There's more than one way to remove a broken bolt other than to drill it out. | ||
| Titusand |
The bolt broke off and it did such that there are threads visible in the head. I suppose my fears are right that the head will have to be removed to replace that bolt? What could cause that? | ||
| Reepicheep |
Jims makes a tool that a reasonable mechanic should be able to use to easily drill out the bolt with the head in place. A little pricey at $70, but at the end of the day it will be fast and easy. Find the right shop and they may already have the tool. Don't use an easy out for sure, it will just make things worse. (Message edited by reepicheep on August 17, 2011) | ||
| Titusand |
It seems to me it must be the nuts became loose and the vibrations eventually fatigued the bolts. | ||
| Gearheaderiko |
Concur with both you and Reepicheap! The head doesnt have to come off, only if you screw up the repair. | ||
| Titusand |
Are the heads of these bolts inside the head of the motor? | ||
| Reepicheep |
Nope, they are studs. A bolt with no head that is threaded on both ends. The threads are different by the way... Loose nuts and vibration can do it, but it is more commonly a result of some other problem with the exhaust mounting system. A worn bushing caused it in my 2000 M2, and a lost front muffler bolt (my own fault) caused it on my 05 XB9SX. | ||
| Titusand |
Here's the story on the broken exhaust stud. 1- The stud broke off with only a small bit of thread left. 2- the mechanic did not feel confident in removing it, so off it went to have the head removed, etc. 3- the cause of the stud sheering was a bad front motor mount, that allowed excessive vibration, which fatigued it. 4- the biggest delay is getting the motor mount. | ||
| Titusand |
Now I get to FINALLY update my profile and list a repair. | ||
| Titusand |
The rubber motor mount had failed. |
