Red Devil Kart Restoration: Engine Rebuild

Today is centered around rebuilding the engine, but we must consider the brakes again. Here is the brake lever which we tried to drill in order to hold the safety tether.

Christmas in May!!

Here are the piston rings...again, from Terry Ives. Notice the original box... and the date.

What a COOOOLLLL box!

Forty-two year old rings! That's original !

Dad uncovered the kart to find this little guy.

It's a Wolf Spider.. on top of a 9/16 inch wrench.... YOU DO THE MATH!

OK.. off to work!

This is looking down the cylinder from the top end.

PORTS! but there are some imperfections

To get rid of the imperfections we need to do some honing.

After the cylinder was cleaned-up, we better take care of the piston and rings.

Notice the pips on the piston rod...by Dad's thumb.

First, the crank needs to go in. But make sure the bearings are all free and oiled. We had to work out what held the crank in place... ah! the yellow cover.

Putting on the cover.

Crank is in. Rings... Ready to go. But wait, not so quick.

The rings must have the correct spacing as noted in the owner's manual. Special tools are required.
The set Dad reached for first in his tool box had not been used in 40 years and were rusted/corroded. I took a chance and checked the kart tool box. After digging around for a couple minutes, there they were. (I knew/hoped he would have them!) Two sets...somewhat rusty under 40 years of dirt, rust, and dust. This one has spanners .016 and .020 inches.

So a few seconds on the wheel and they are almost perfect.

RINGS! Easy does it! Don't move quickly. Don't bend them!

Here they are in the grooves.

It is hard to see, but the yellow cover is nearly blocking the cylinder. It needs to be twisted so the short skirt allows the arm to be placed into the cylinder, then the twist the piston back into position. IMPORTANT: the arrow stamped in to the top of the piston needs to be nearest the exhaust ports.

Once the piston is in, the careful work starts to get the rings in. Slide in to the bottom ring, compress the ring from the bottom up to close the gap. BING! Just a little pressure and it pops in.

The bottom end, with crank shaft and piston arm.

Ready for needle bearings!

Need a little dab of grease. Make sure there is no grit or grime or dirt... like this little black dot of dirt.

Needle bearings! There are 24 bearings... COUNT THEM AND COUNT THEM AND COUNT THEM.

Use a magnetic screw drive to move each bearing to the crank. Place in the space between the crank and the piston arm.

Bearing is just peeking out on the bottom.

Magnetic screwdriver makes the work easier. GO SLOW! COUNT THE BEARINGS!

It looks easy, and it is. But I dropped one bearing into the crank case. Found it and put it back.

When half the bearings are in, put the other half in.

Here is the bottom end all together. Turn the crank (on one direction) to make sure the grease is working in and there are no gaps. But there was a slight gap. Turned the engine on end and shook. OOOPPPSSS!!! a needle bearing popped out. So do it again.

Turn the bolts to just tight.

AHHH, my first crack at using a torque wrench.

With the bottom end done, the head can go on. Just watch which way the it is aligned. But to tighten the head screws with the torque wrench we needed a longer straight allen wrench.