Here is the second “How To” provided by Joe over at CrimeScene - this one is all about splitting the rockers on your Ironhead Sportster. I absolutely LOVE this look - really makes the Ironhead engine a looker. If I had one of these Sportsters, it would be at the top of my lists of things to do. Dig into it!

Splitting the Rockers on an Ironhead Sportster
By Joe CrimeScene

Here is the step-by-step sequence I did on splitting the rockers on my ironhead. Weyland was the inspiration for this method of cutting them, and in my opinion it is the best looking result. Just splitting them will leave you with mis-matched rockers (one square and one rounded) on the Ironhead.

Here is where I started. I sketched out some shapes first, until I liked the basic look.

See how they are square on one side and rounded on the other? That is the key thing to deal with. The brass nut is from Weyland, it screws into the end of the rocker shaft.

I used a little pattern tool to pick up the shape on the curved side and transfer it over to the square side

OK, time to get serious. Fire up the mighty Do-All and whack off the corners.

Note that I made the cut short of the hole where the rocker shaft come out. I wanted to make sure I had enough room to weld and grind without getting into the holes. When I’m done I want this side to taper down _almost_ to the shaft hole to match the other side.

We’ll need to do something about that hole or there will be a big puddle on the floor…

I cut out the “bridge” between the two sides. There is an oil port on the square side that feeds both shafts (through this bridge part). We’ll need to plumb both rockers later.

I attached the middle area with a no-load grinding disc (specifically for aluminum). I wanted to round it over and get a nice flow going.

Use the flat of the disc, not the edge, and it is really controllable.

If you compare this with the shot of the rockers boxes just after they were cut apart you can see how much material I hogged off. It goes quickly enough.

I wanted to rough these in because I have to weld up the oil galley that runs all the way through the covers.

Once I hogged the buld of the material off I used a counter sink to bevel the hole and welded it up. Then I dressed it down a bit further with the belt sander.

The belt sander is one of my favorite tools. It can hog off metal, or do a really fine fine finish.

Here is the middle section roughed in. Now we need to close up that ugly hole.

And we need to weld up the oil passage too.

I did the “dirty finger” template thing, and started making a little plug to fill the hole.

Here is the part fit into place.

I used a junk rocker shaft to try to control distortion, we will be making this really, really hot for a while. I welded around the seam, then build up the surface with several passes so that I had some material to shape.

Pretty much done, I checked the rockers side-to-side with a template to make sure they matched. I took them up to 320 on a D/A sander to get everything nice and smooth.

With the brass nutz from Weyland mocked up (no shafts)

Add chrome, polishing the nutz, Weyland’s hex covers on the pushrod tubes and some assembly and you get…

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Thanks again to Joe at CrimeScene