Harley Ironhead Pistons and Cylinders
Life's a bitch... Thank God there's Harleys...
It took a while, but we've got our cylinders bored, and we've got a new set of oversize pistons to match. Our overhauled 1973 Harley Davidson Ironhead Sportster engine is starting to take shape!
Cylinder boring did not go without problems. Actually, one of the cylinders had to be replaced by a "new" one.
Click HERE to read the story.
Ironhead Cylinders and Pistons - Ready to Install
Here's an overview of the refurbished cylinders, new oversize Ironhead pistons, new piston rings, and new cylinder gaskets, ready for mounting into our Ironhead engine.
The new oversize pistons are by Motorcycle Storehouse and - as far as we are aware - are the largest size available. Piston rings by Hastings.
Ironhead Engine Taking Shape
Here's the new oversize Sportster pistons fixed to the connecting rods.
Next step: Front cylinder in place!
Both cylinders have been bored to 82.5 mm diameter. The stock stroke of an Ironhead engine is 3.8125 inches or 96.8 mm.
So, after boring this is now a 1035 cc engine!
Just for reference:
BEFORE Cleaning and Rebuilding (May 2008)
Just for reference, this is how our 1973 Harley Sportster Ironhead engine and cylinders looked like in May 2008 before cleaning and rebuilding.
CLICK HERE for more details on this heap of dust and grime.
And now:
AFTER Cleaning and Rebuilding (April 2009)
This is how she looks like at this stage of overhauling.
Can you imagine that even if this Harley Ironhead engine has not run yet, she has already given us a lot of satisfaction?
April 2009
Ironhead Engine Assembly Steps:
- Step 1 - Engine Case Assembly
- Step 2 - Oil Pump
- Step 3 - Cam Gears and Cover
- Step 4 - Installation of Primary Chain and Sprocket Wheels
- Step 5 - Fixing of the Compensating Sprocket
- Step 6 - Clutch Unit: Parts Cleaning and Preparations
- Step 7 - Clutch Release Disc: Installation Using Spring Compression Tool
- Step 8 - Startmotor: Cleaning and Inspection
- Step 9 - Startmotor and Bendix: Install and Test
- Step 10 - Primary Cover Back in Place
- Step 11 - Main Shaft Rollerbearing
- Step 12 - Oil Seal and Sprocket


Jan's 1976 Zundapp GTS50 Moped
Frans and his 1970 Jaguar XJ 4.2