The Aermacchi Project, Part 3: Moving a Head and Making Tools 101

Reader Contribution by Margie Siegal
article image

Wrenches modified on the bench grinder to aid in removing the Aermacchi’s cylinder head nuts. Photos by Margie Siegal.

This is the third installment of an ongoing series detailing Margie Siegal’s restoration of a 1973 Harley-Davidson 350 Sprint. You can read the Part 1 here.

I looked at the nuts holding the Aermacchi head down. They looked back at me. The two on the right side were recessed into little caves in the fins. There was no way a normal wrench was going to fit here, let alone a socket wrench.

I re-read the service manual. It said to take the four nuts off, and then the head was supposed to slide right off the head bolts, unimpeded by a head gasket. It also said that you needed a “thin bladed wrench” to get the right side nuts off. Off to find the right wrench. It doesn’t exist. Next step: MAKE the right wrench by grinding down an existing wrench to fit. This will be A Learning Experience. I do have a grinder, but have never used it.

A visit to a swap meet resulted in three open-end wrenches that had originally been part of a Honda tool kit, for the sum of $5. A visit to O’Reilly’s garnered a nice long wrench with both open and closed ends for $10. My volunteer mentor, Dave Kafton, suggested that the closed-end wrench might be the best solution. He also said that if I was going to grind the wrenches down to fit, I needed to have a pot of water near the grinder so I could dunk the wrench I was working on every so often. “That way, you maintain the temper.”

I found a nice, heavy-duty shop apron and a pair of work gloves. Home Depot has face shields that will guard against flying metal and not fog up. I turned on the shop fan, put on my safety gear and went to it. The old grinder went through my cheap wrenches quickly. I tried to round off rough edges as I went, dousing the wrench in water every five minutes. When a reasonable amount of metal had been taken off, I started checking the wrench against the bolt caves.

Rust on one of the four cylinder head studs made removing the head a bit harder than it should have been.

It took less than a half-hour per wrench for this newbie to modify two 17mm wrenches — one open end, one closed — to fit into the space with the nut. Interestingly, I didn’t have to take off any metal from the perimeter of the closed end wrench — just the top and bottom. I squirted the nuts with WD-40, tapped them and started in.

One nut off. Two nuts loose. More WD-40. Some Liquid Wrench. Tap tap with a copper hammer. Try a different angle. Third nut loose. Fourth nut loose. Success! Nuts and special thick washers off and stored in labeled baggie. Now to get the head off …

It won’t budge. Damn. Tap tap. Drown the thing in Liquid Wrench. Tap tap. Nothing. Swearing doesn’t help. It’s time for me to stop for the day before I break off a fin. I complain to friends. One suggests I try squirting WD-40 down the spark plug hole and pushing on the kickstarter, so a few days later I try it. A crack opens! Squirt Liquid Wrench down the crack. Tap tap. It’s moving! I am moving a head!

Once I get the head off, I see the problem: one of the bolts had a rust spot and welded itself to the bolt channel. Next step is to see how deep the rust goes while the Norman Racing machine shop is doing the valve job. Stay tuned for the next episode of “as the wrenches turn …”

Motorcycle Classics Magazine
Motorcycle Classics Magazine
Motorcycle Classics Magazine Featuring the most brilliant, unusual and popular motorcycles ever made!