Punkskalar
Hugh's HandBuilt
This is on the Father In Law 70s style chopper I have been working on...
My FIL had the head "rebuilt" somewhere by somebody who didn't have a clue what they were doing obviously... The spark plugs threads were all buggered up, so they installed the infamous "Spark Plug Repair Kit" that you can find at all your favorite auto-repair houses.... This particular style NEVER works well in aluminum heads, but they installed it anyway.... So needless to say, I now had 2 really large holes in a the head of this bike where spark plugs wished they could reside along with some inserts that wouldn't stay in...
I tried ALL the hardware places in town, but nothing was going to fix this short of me pulling the head, welding it up, drilling and retapping... I had no time for that, so I made my own new inserts, something that can't be found online or on the shelf somewhere... After a few careful measurements with my eyecrometers, I whittled these down from some 7075 Al.
M14x1.25 threads ID, and 3/4-16 Threads on the OD.
I took my time drilling out the head, making sure the valves were closed so as not to knick them with the drill (it was a very close fit). If you are really careful, and coat your drill in some super tacky grease, you won't get any chips inside the cylinder.
All drilled out and ready to be tapped. I stepped up the hole in 1/16" increments until I was at 11/16". I coated the tap in grease just like I did the drill bits, and miraculously didn't get any chips inside the cylinders.
I used a liberal coating of RED Lock-Tite and installed the new inserts using an old spark plug. I let it sit for a few hours, hit it with some heat and then removed the plugs. I installed new plugs, and took it for a test ride! It was nice making it more than 20 feet without blowing out a plug.
My FIL had the head "rebuilt" somewhere by somebody who didn't have a clue what they were doing obviously... The spark plugs threads were all buggered up, so they installed the infamous "Spark Plug Repair Kit" that you can find at all your favorite auto-repair houses.... This particular style NEVER works well in aluminum heads, but they installed it anyway.... So needless to say, I now had 2 really large holes in a the head of this bike where spark plugs wished they could reside along with some inserts that wouldn't stay in...
I tried ALL the hardware places in town, but nothing was going to fix this short of me pulling the head, welding it up, drilling and retapping... I had no time for that, so I made my own new inserts, something that can't be found online or on the shelf somewhere... After a few careful measurements with my eyecrometers, I whittled these down from some 7075 Al.
M14x1.25 threads ID, and 3/4-16 Threads on the OD.
I took my time drilling out the head, making sure the valves were closed so as not to knick them with the drill (it was a very close fit). If you are really careful, and coat your drill in some super tacky grease, you won't get any chips inside the cylinder.
All drilled out and ready to be tapped. I stepped up the hole in 1/16" increments until I was at 11/16". I coated the tap in grease just like I did the drill bits, and miraculously didn't get any chips inside the cylinders.
I used a liberal coating of RED Lock-Tite and installed the new inserts using an old spark plug. I let it sit for a few hours, hit it with some heat and then removed the plugs. I installed new plugs, and took it for a test ride! It was nice making it more than 20 feet without blowing out a plug.
