Was given this early 1973 CB250 frame and wheels for a job I did for a friend, and I have a CG250 engine here that needs a home so going to see what I can make of them. Long term project as and when I find bits to fit.
As the supplied rear wheel didn't come with axel, I made one from 19mm bright bar turned down to 17mm to fit the wheel, made spacers and chain adjusters too.
Front rim had a couple of nasty flat spots and the disc was too close to a fork leg. I took it all apart and machined 5mm from the disc mounting surface. I thought about making a male/female die for the press to straighten the rim, but found a new one with the 40 spoke holes from India for $87 delivered so will be fitting that when here.
The forks didn't come with a top plate so I found a place in Brisbane that sells small bits of alloy for reasonable prices (https://www.ebay.com.au/str/red5metalworx/16mm-Dia/_i.html?store_cat=70583622013) and ordered a 100x25x300mm piece of 6060-T5 alloy flat bar. This was placed beside the bottom yoke and marked off. I turned up some bushes to use to find the centres of the holes needed to drill. Clamped together and spot drilled before putting in drill press for bigger holes. For the fork holes I used a 32mm hole saw and 19mm drill for the stem. By using a piece of large heavy angle, I bolted the plate to the carriage on the lathe. I fitted a cutting tool into a spigot I had made for something else but was the right size to carefully cut the holes out to a finished 33mm to suit the forks.
Then cut off all the extra alloy not needed and bolted to the drill press set at 90 degrees. This enabled me to get the clamping bolt holes drilled and threaded. After grinding down to finished size I placed two 1mm cutting disc into grinder and sliced through to the fork holes. A sandblast and fitted. Now I just need to remember where that safe place was that I put the handlebar clamps and I can drill for handlebars and instrument mounts.
I rebuilt these Koni shock a while ago and today got them out to fit up. They needed to have the bottom mount changed from an eye mount to a clevis. I made two clevis to fit the Honda swingarm, cut the eyes in half and welded the clevis on. I had to bore out the top eye from 14mm to 16mm to fit the frame. Fitted.
I found the bar clamps and fitted. Made a battery box and fitted the solinoid under it. Modified the manifold to fit the carb to left side. Next will be starting on sorting the wiring.
Up date. Made two new sidecovers from some 1.6mm aluminium sheet, welded the pieces of the exhaust pipe together, mounted the CB125 tank (yet to be repaired), the Kawasaki seat needed to be modified to fit, then repaired where the edges had rusted away. I cut two strips of 1.2mm sheet and heated and welded to seat base. Long way to go yet.
Stripped the frame down ready for sandblast and painting. Welded on two nuts for attachment of the sidecovers I had made. Getting the swingarm pivot bolt out required a lot of pounding with drift and four pound hammer. The bush was rusted in and needed some help from the press. The plastic bushes were shot so will make some new ones from nylon bar. Also added a grease nipple so this will never happen again.
I bought some black nylon bar and made two new bushes. I made them slightly smaller so I could machine the metal sleeve round again and still be a tight fit. I assembled the bits and had to polish out a few thou with emery cloth on a stick to make a light tap in fit. While the frame paint was drying I stripped the forks. Think the last time the oil was changed was in the factory in 1973. A good clean, new seals and oil and ready to fit. I had to rebuild the rear wheel too, but need to buy a new tap to be able to clear the rusted nipple threads before reassembly.
