I don't have a good before picture, so this is about half done.

The headlight on the quad wasn't original, had water in it and was taped together with an entire roll of electrical tape.

The new LED headlights are much better!  I machined an aluminum plate to mount them.  We had to do some electrical tricks to get one to turn on for low beams and both on for high beams.  We added a large diode and properly soldered and used heat shrink on the wires.  The original high/low beam switch still works, and turns on one light for low and both for high.

The upper engine mounts were completely missing, and the engine rocked around while barely running.

So we made a cardboard template, measured it, drew it in SolidWorks, and CNC machined new ones.  It's very solid now.

The original carburetor was clogged up, but it was still technically running...  I couldn't find a rebuild kit for it, so we replaced the entire carburetor with a new one.

The brake fluid cap was cracked in half, probably because it had been overtightened.  I modeled up a replacement in SolidWorks, and 3D printed a new brake fluid cap for the rear brakes.

The clutch and brake levers were loose and floppy, so I rebuilt them with new machined bushings using the metal lathe.

The hand grips were worn out and missing large chunks.  We replaced them with new black and red grips.

We replaced the seat cover, as the original was torn and covered in old duct tape.  We also made a new chain guard around the front sprocket, as the top half of the original guard was snapped off the gear case.  We had to repair a tapped hole in the bottom of the gear case as well, as it was stripped badly.

We completely rebuilt the front suspension, bearings and brakes.  They were all really bad!  They had not been greased properly over the years, and were completely worn out.

My dad couldn't believe the wheels hadn't fallen off!

We also replaced the brake pads, bled the brakes, and repainted the brake rock covers.

The slider bolt for the rear caliper was stripped, so was the female threads where it bolted in.  We drilled out the male thread and tapped a hole, and threaded in a new length of male thread.  We welded in the missing female threads, drilled it out and tapped it.  It would have been over $100 to replace these parts.

The rear suspension was worn as well, so we disassembled it.  The rear bearings were as bad as the front, so we replaced those as well.  The rear brake rotor was badly bent, which had caused the stripped threads on the caliper, so we replaced that too.

We pulled the engine to clean up the outside, and check the inside too.

The more we checked, the more we had to fix or repair.

It was a bit dirty inside, full of metal from the old clutch.  We cleaned everything out, replaced the seals, gaskets, and lock washer plates with new.

Luckily, the gears and shifting forks were all in good condition, it just needed a clean.  We did have to fabricate and add a .020" thick shim washer to the forward/reverse shift arm (top left) as it wouldn't shift properly due to wear.

Notice all the metal debris in the bottom.

We found teeth missing from the starter intermediate gear.  Had to replace it.  The starter was also dead, so we replaced that too.

The sprag clutch was so worn the sprags had flipped the wrong direction, making the starter spin really fast when the engine tried to start.  We had to replace this gear and sprag too.

When we tried to set the vavlve lash, we found it was nearly 1/8"!  It should be .003-.004"!  The end of the valve looked like a mushroom.

We had to grind the end of the valve inside the engine with a dremel tool to even remove it.  We replaced both valves and valve seals, and my dad taught me how to lap in the new valves so they would seal properly.

We sealed the crankcase together with Yamabond.  The head was finished and installed on the cylinder.

We replaced a bunch more parts around the clutch.  Luckily the clutch was in good condition.

We got the engine in, the clutch and parking brake readjusted

We had to make new mounts for the exhaust heat shield as they had bolts snapped off in them, and it was hose clamped on. We cleaned up, painted and installed the exhaust.  There were several stripped tapped holes on the frame, so we welded them in, drilled and re-tapped them the right size.

It's nearly done!  I got some practice using the clutch and shifting through the gears.

It's missing the front bumper and foot protection.  Time to find some tubing.  We also made a new lower chain guide from 3D printed plastic and CNC machined aluminum plates.

I found some nerf bars that I liked, but they were almost $200!  We used some old steel tubing my dad had from an old go cart roll cage to make protection for my feet.

  I got some good welding practice.  We added supports for the rear fenders as well to stop them from flopping around.

Nerf bars are done! If you look closely, you can see some notches for the brake lever.  The notches are pieces of square tube welded into a notch we ground in the round tubing.

We installed new handle bar grips.  Much better!  I still need to glue them on though.

We had some tubing left after building the nerf bars, so I wanted to make a bumper.  My dad showed me a trick to tape the two plates together with double sided tape to drill, cut and belt sand both plates at the same time so they came out the same shape and size.  Here it is just after I finished welding it.

 And here's the bumper with a new coat of paint.

We also bored out and replaced the pivot on the rear brake lever, and while it was off, painted it black.

Same for the shifter - it is much smoother and no longer floppy.  I can get credit for this in my art class at school!