Alright, so I’ve been tinkering with this 103 twin cam engine for a while now, and let me tell you, it’s been a journey. I figured I’d share my experience here, step-by-step, in case anyone else is thinking about diving into this kind of project.

Getting Started
First off, I got my hands on a used 103 twin cam. This thing was not exactly in pristine condition, but that’s part of the fun, right? I started by giving it a good once-over. Checked for any obvious damage, made sure all the major parts were there. This wasn’t my first rodeo, so I knew what to look out for. But even if you’re a newbie, just take your time and inspect everything carefully.
Tear Down
Next up, the tear down. I grabbed my tools and started taking this bad boy apart. It’s kind of therapeutic, you know? Unbolting, unscrewing, carefully labeling everything so I’d remember where it went later. I made sure to lay everything out in an organized way, too. I took photos of the process of my work. Nothing worse than having a pile of parts and no clue how they fit back together.
- Removed the heads: This was pretty straightforward. Just a few bolts and they came right off.
- Took off the cylinders: A little more involved, but still manageable. Had to make sure I didn’t damage the pistons.
- Pulled out the pistons and rods: This is where things got a bit trickier. Had to use a special tool to compress the rings, but I managed.
- Inspected the crankcase: Looked for any cracks or wear. Fortunately, it was in decent shape.
Cleaning and Inspection
Once everything was apart, it was time for a deep clean. I used a whole bunch of engine degreaser and elbow grease. Got all the gunk and grime off every single part. I scrubbed and wiped. Then, I inspected each component closely. Looked for wear, cracks, anything that might be a problem down the line. I replaced a few gaskets and seals that were looking a little worse for wear.
Rebuilding
Now for the fun part – putting it all back together! I basically reversed the tear down process, but this time with shiny, clean parts.
- Installed new piston rings: This was a bit fiddly, but I got it done.
- Put the pistons and rods back in: Made sure everything was properly lubricated.
- Reattached the cylinders: Torqued the bolts to the right specs. Don’t want any leaks!
- Put the heads back on: New head gaskets, of course.
Finishing Up
After getting everything back together, I added fresh oil, checked all the connections, and then it was time for the moment of truth. I hooked it up and fired it up. It sputtered a bit at first, but then it roared to life! Music to my ears, let me tell you. I let it run for a while, checked for leaks, and made a few adjustments.

This whole process took me a few weekends, working on and off. It wasn’t always easy, but it was definitely rewarding. There’s something special about taking an old engine and bringing it back to life. And now I’ve got a sweet 103 twin cam that’s ready to hit the road. Hope this inspires someone else to take on a project like this. It’s a blast!