Here I hope to change a 15/17 head to a 16/19 it was not planned like this. But when discovering a broken glider I had no choice. 
I have to renew the gliders and then I will use the 4,5mm valves because I have more options in those.
Lets see how far I come.
								
									Broken valve glider.
								
							
									Sadly it broke.
								
							
									You can see it was longer like that.
								
							
									Have to renew the gliders, now i will use the 4,5mm valves as they are easier to get hold off. 
							I have a new 16/19 set so will be using this.
First i need to make a Tool to enlarge the ports.
								Start machining a disk with an M12 bold in it.
								
									Weld the bold say it stays put.
								
							
									Machined it flat.
								
							
									Slowly start machining it to a 4,5mm
								
							
									Used a center to keep it straight.
								
							
									There she is 4,5mm
								
							
									Red paint dot on M6 holder
								
							
									Now where to drill.
								
							
									9,5mm hole.
								
							
									Holder placed in head.
								
							
									Tighten the bold.
								
							
									Mounted the head.
								
							It looks like it's perfectly centered.
								
									You see it spinning.
								
							
									Enlarge the ports.
								
							
									Some more space for the 19mm valve.
								
							
									Machined it with a grinder to smooth thinks out.
								
							
									There she is a 16/19 setup.
								
							The next challenge is to machine new glides
Start off making the valve guide.
								
									Making the outside 9mm.
								
							
									Center hole
								
							
									4,4mm drill
								
							
									4,5mm reamer
								
							
									Done
								
							
									A nice 4,5mm hole
								
							
									Small angular
								
							
									Made two, 0,05mm larger
								
							
									Looking good
								
							
									Tool for hamering them in
								
							
									Fits perfect.
								
							
									Mounting them
								
							
									Done.
								
							
									Final 4,5mm hand reamer.
								
							
									Nice and tight.
								
							
									Valve grinding
								
							
									In action
								
							
									Measuring the cut out for the inlet valve
								
							
									Cut it out off the cilinder
								
							
									Flatten the cilinder.
								
							
									Looking good.
								
							
									Ready for mounting.
								
							
									Changed the gasget to.
								
							
									Looking good, just above the top piston ring
								
							
									Looking good
								
							
									Running Motom