Creating my own motorcycle scratch

[Old England]

Respect!
RussN

Indeed!
I have been engaged in similar work in the distant past. So many opportunities to make mistakes!

H

I saw an example of the incredible precision work you did years ago Harold, much more respect! And yes mistakes were made occasionally during this project but with a bit of magic they became features
Cheers, Carl.

[Patio]

Carl, thanks for starting this thread. I am a motorcycle enthusiast myself. I will be watching your thread. Very nice work and good inspiration for one like me.
Thanks!

[Old England]

Carl, thanks for starting this thread. I am a motorcycle enthusiast myself. I will be watching your thread. Very nice work and good inspiration for one like me.
Thanks!

Hi Pat, thanks, so glad you find it interesting and I hoped it would inspire others to have a go. I'm a bit busy with work at the moment but will try to post photos of the cylinder head later today.
Carl

[Old England]

This will have to be the last post for several days as mucho work coming in, I do find I get much more tired these days so most evenings for a while I'll probably be snooozing Lots of photos this time though of the cylinder head being created.
Fairly straightforward but a lot of planning each move and the sequence. First up the billet was squared up, centre of the combustion chamber found and the stud holes drilled plus dowel recesses. I pondered for a while on how to machine the combustion chamber, in the end this is how I did it on the mill. I made an extra long extension for my small boring head then the cutter was set at the centre of the chamber. Rotating the rotary table whilst the cutter rotated produced the desired partial hemisphere by feeding in with the X axis. I had a very stiff left arm for a few days after rotating that table what seemed like hundreds of times!
Next on to the machine vice to drill and ream the valve guide holes and rough out the ports. After all this effort I had to do a trial fit on the cylinder.
Possibly the most nerve racking part was cutting the fins over the combustion chamber, plenty of possibility for disaster! Final shaping was done on the Alexander Master Toolmaker mill to get into the awkward spots.
Finally, hours and hours of Dremel, abrasive paper and bead blasting and it was done.

[Old England]

Had to add this photo seperately.

[Harold_V]

Outstanding!

H

[JackF]

I can only dream.

[Old England]

Thank you gents. When you are enjoying yourself as much as I was it's half the battle and during this first year virtually every spare hour was spent in the workshop, kept going by endless cups of tea made by my wonderful wife!

[NP317]

A fantastic Team effort!
RussN

[Odyknuck]

Simply WOW! CNC quality on a manual machine, impressive!

[Steggy]

Had to add this photo seperately.

The cylinder head almost looks as though the factory made it. Great work.

[Old England]

Thank you for your kind remarks gents, and yes my wife is a key member of the team, she has retired from racing now but was nicknamed 'Hooligan' by a fellow racer for her full on no prisoners style!
My method for creating parts from billet sort of mimics CNC in that parts are drawn in CAD (but in 2D old style), I then draw tool paths for the cutter to be used for each operation and print this of for use in the workshop in combination with the mill's DRO. I use an optical edge finder by BIG Daishowa as used on CNC machines. This tool has paid for itself many times over as it's so quick and easy to use.
In one of the previous photos you can see the gear type oil pump I made, it uses commercial gears and the scavenge side has double the capacity of delivery. At the time the photo was taken the layout of oil lines was speculative as you will see later.
OK more photos:
First up the rocker shafts and arms. The rocker arm which bears on the valve stems is welded to the shaft and carries threaded adjusters for clearance. The outer rockers which bear on the push rods are a press fit on a very coarse spline, they are made from mild steel but the socket for the pushrod is tool steel welded onto the rocker. This bi-metal approach seemed the easiest way to tackle construction. Shafts run in bronze bushes in the support plates.
The next photo of the engine shows the setup without the inner rockers which could only be welded on when the valves were installed completely. The finned exhaust clamp was a source of much much grief; I think I thought it would be a nice straightforward milling job and consequently didn't think it through properly. The result were two scrappers before I got my offsets right.
I decided to use a modern Mikuni carburettor for a Yamaha 500 rather than some period type as I hoped this would be tuned close from the off, and this proved to be the case.
Year 2 and on to the frame: Fabricated in mild steel tube on a simple welded jig I've used to build a few other frames. The tight bends at the bottom of the downtubes were too tight a radius for my manual pipe bender but I managed to get them done by a specialist company at a good price as they were interested in the project. All other tube bending was achieved with muscle power in my shop. I managed to score a bare set of late 1920's girder forks on eBay at a good price as no on knew what bike they were for.
Now I had forks it was back into the workshop to make yokes, steering stem and friction damper as shown in the next pics. Once again Dremel, files and abrasive paper followed by bead blasting.