Well, here's the next instalment in the saga of the 'Big Pussy'
.
No pics of the motor yet but this is what I've done on the gearbox.
I have turned-up a second kickstart sleeve. This time I ran the lathe in reverse with the cutting tool inverted as that let me start at the shoulder and then cut cleanly into the open air. Running it the other way gives me problems as I have to stop the lathe before the cutting tool hits the shoulder at the end of the thread. Its a heavy chuck on a very heavy drive mechanism and I have mis-judged it a couple of times
.
This new approach works but I'm still not satisfied. I'll make a third one sometime.
Here is No 2 with No 1 alongside. I have left the new one a bit long and I'll trim it to size later.
On this occasion, I finished the machining with the sleeve in the end cover. This worked and if I screw the alignment mandrel I made at the beginning into the face plate . . .
It aligns perfectly with the new sleeve. The first one was a couple of thou' out and when I trued it up it was a bit too slack on the shaft.
.
Now for the kickstart shaft . . This runs on the end of the layshaft and contains a large bronze bearing sleeve. The sleeve was worn allowing the kickstart to droop - putting weight on the alloy sleeve, which cracked-up.
The worn sleeve is in here:
I tried drawing the bronze sleeve out with a slide hammer, but it wasn't having any of that and refused to budge.
Only one thing for it then . .
I used a Glanze boring tool like this:
It didn't take long to reduce the bush to a shell.
After which I used a sharpened 'Obo nail' to bend the wall in and free it. I didn't want to risk cutting into the shaft with the boring tool.
Notice the shoulder in the hole, the bearing sleeve has a flange on it.
Next, I set up 250mm of (very expensive) hollow bronze rod in the lathe. These are supplied oversize which is fortunate as the nominal size is the same as the sleeve diameter (one inch).
First it was trued to the flange diameter.
Then the body was turned-down to just over the diameter of the hole. Finally I bored it to the diameter of the layshaft spigot.
Here it is ready for pressing into the kickstart shaft. I made the flange thicker than necessart for two reasons.
1. I wanted plenty of metal on the flange when I pressed it in.
2. I intended to turn the face down to match the clearance in the kickstart gear rather than go from measurements of the old bush.
And here it is pressed-in and face-turned to the finished depth.
The kickstart shaft now attaches to the layshaft without any sag
Of course, once 'Robmack' has been jumping up and down on the kickstart for a while things may be different
.
So, tick-off one more item from the task list
.
I now have the 500cc motor (or, most of it). If anyone is interested I'll start another restoration thread for that.
Anyone interested ???
Bob.
).
.
.
keep posting please.
