Made some new allen head screws to replace the broken flat head screw for the kickstart plate inside the case. Had to turn them in the drill press and use a dremel cut of wheel to shape the heads smaller. Also had to open up and tap the holes in the case to beef up a little from m5 to m6. The kick start plate is hardened steel, so the holes had to be opened slightly with a tungsten cutting bit and countersunk with a tapered grinding stone. Total pain in the ass, considering I could have just kept it the way it was. Ehh, oh well, should be stronger now then it was stock. Did some other odd jobs with the motor like going through the stator with fresh wires, new condenser and a set of new points I ordered from Italy on eBay. I believe the part number is "CT 0132407" in case the link doesn't work.
(Dansi Points Link)
The exhaust port was cleaned up with a gentle dremel grinding stone and then with sandpaper. If you use a knitting needle (like I did) or any other slender rigid piece of tube and cut two slits up it vertically on both sides, it can be wrapped with a strip of sand paper and be chucked in a drillpress or hand drill. Only takes a minute to make the tool, and makes smoothing intake and exhaust ports pretty dang easy. Could be used on the inside of the intake itself, or anything really that could use a smoothin'.
Also made all new case and cover alignment dowels out of some 7/16" aluminum tubing I picked up from Ace hardware. It was a hair over 11mm, so I cut sections and and chucked them in the drillpress and used sandpaper to turn them down, using calipers along the way. They all turned out nicely.
Although I'm only focusing on the engine at this point, the inside of the tank could use a good bit of love. I used Evaporust I picked up at the auto parts store for $30 a gallon. The tank soaked for hours on each end. It cleaned the rust really well, but didn't do so hot with the goo and varnish that I'm assuming was adhered to relatively clean metal. The rest of the varnish and goo on top of the rust was removed when the rust underneath was washed away.
If cleaning a nasty tank like I had, I'd suggest filling the tank with wood screws or the old nuts and bolts that you've been hoarding in a coffee can, filling the tank halfway with vinagar and shaking the shit out of it for a bit to realllly beak up the chunks of varnish, rust, goo and other big stuff that's in there. Then soaking in white vinager for a week or going the evaporust route to remove the remaining rust back to a clean metal surface. But after all that I'd really suggest lining the tank. I used Red Kote that I bought online for around $25 a quart. It's enough to do a good sized tank about 3 times. From what I've gathered, Red Kote is MEK based, so it can be safely thinned out with MEK from any paint or hardware store.
The little badge emblem on the ignition side of the motor was scarred up and I'd like to replace it but haven't been able to find one. However, I took a photo of it from above and recreated it on my computer. It's not an exact replica of the original image but its pretty damn close. I made the image into stickers and plan on just sticking it onto a round plate cut from thin acrylic sheet and using small screws to attach. It'll look nice and close to original too.
A NOS 60mm standard piston, set of rings and wristpin came in the mail too. The rings were gapped perfectly in the bore out of the box, the piston feel through nice and smooth with a slow fall with the cylinder face down on glass, but the wristpin was crazy tight. According to Graham Bell, the wristpin should almost be able to fall through the piston under it's own weight. If the wristpin is tight or pressed in, it could take the piston out of round when the piston is heated and expanded when running. This will cause uneven wear of both the piston and cylinder wall. To fix this, I used a socket (3/8 to 1/4 adapter) that was a verrrry close fit to the wristpin holes in the piston. Then I chucked it up in the drillpress and used a drop of lapping compound around the socket. After that I simply held the piston in my hand and worked the socked in and out, cleaning the lapping compound out of the piston with a shop towel periodically and checking the wristpins fit. Now with a gently push it slides through very smoothly. Without a drillpress I'd probably be lost.
Also the exhaust header will be used when everything is going back together, but I don't plan on using the stock muffler. I'll probably use a clamp on chamber. So as for cleaning the carbon and shit out out of the header, I heated it red hot with an oxy acetylene torch, and let it air cool. Propane or mapp gas will work just as well but will take a bit longer. After that I welded a small wire brush to a strand of cable and fished it through a few times with a wad of steel wool and brake cleaner. Pressure washed it out, although it probably wasn't necessary and sandblasted it inside and out.
Before cleaning tank
After Evaporust
After first coat of Red Kote
DIY alignment dowl
Inside of cleaned exhaust header
Before smoothing exhaust port
After smoothing exhaust port
Clutch discs and bell bead blasted to remove discoloration and rust
Fitting piston for wristpin
Dented and not flat ignition cover plate
Ignition cover not flat either!
Ignition cover was milled flat and the ignition cover plate was lapped flat with glass and sandpaper
Ignition cover plate emblem all beat up
Remade emblem (Feel free to use!)
New big end pin cut down to length on the lathe.
PRO-X Honda DIO rod pressed into the Yamaguchi crank halves
