On The Road Again

Shovelhead Exhaust Flange Fix On The Fly

Article & Photos By: Daniel Donley – www.pandemoniumcustomchoppers.com

Originally Published In The January 2016 Issue Of Cycle Source Magazine


Got a call from a good friend of mine, Chris Thompson, who has been out traveling the country all summer living life free. He asked if he could stop by and do some much needed repairs on his bike; his rear exhaust pipe was falling off his shovelhead and he needed to get it back on so he could get back on the road as soon as possible. I told him to bring it by and we will get something fi gured out. So on a Sunday afternoon he stopped by and we got to work.


You can see here that the threads for the exhaust bolt on the rear cylinder head have just decided to give up. This makes for a bad exhaust leak! I have seen this many times with Shovelheads so nothing new here. Since it is Sunday afternoon and Chris needs to get back on the road we are going to have to wing it here!


You can see the bolt threads had previously been repaired with a Heli- Coil, the threads in the aluminum had decided to give up and therefore the Heli-Coil was backing out of the head.


Not having a Heli-Coil on hand to fi x this we decided to make a thread insert from a 7/16 bolt.



Chris is drilling out the wonky threads and tapping them to size for the homemade insert. 7/16-14 Tap and a U Drill are used here.




I cut the threaded portion of the 7/16 bolt off and drilled and tapped the center of the bolt to 5/16-18 thread; this will be used for the new thread insert for the cylinder head.


I Used a 5/16-18 bolt and nut as a driver to install the new thread insert into the cylinder head.


Chris is using the driver we made and installing the new thread insert into the cylinder head, we used green lock tight here for good measure.


You can see that the newly installed insert is sticking out past the cylinder head so we will need to grind that off fl ush. I made the thread insert too long to be able to take advantage of all the threads in the cylinder head would let me have.


Chris is grinding away on the thread insert making it fl ush, he is not even giving a shit that he is throwing sparks all over his bike. O-Well it has to be done, better him than me


You can see that the thread insert if flush with the cylinder head.


Chris ran a tap through the threads to make sure everything is 100% and blew the threads out with some compressed air.


Now to reinstall the exhaust systems so Chris can get back on the road again. It was a great day hanging out with a Chris, who I hadn’t seen in a while, it’s always good to hang out in the shop, turn a wrench and catch up with friends

You must be logged in to post a comment Login

Want more information on advertising with Cycle Source in Print or On-line? Email us and we’ll send you info today!