One goal with the bike is to reduce weight. In many instances the different aluminum alloys are the metals of choice. We are all familiar with them. One drawback of these are it is hard to design fatigue resistance to cyclic loading and sometimes more strength is needed than they have. This is where titanium, both the commercially pure (CP) grades or the alloy grades, are the better choice.
One job is to make two engine mounting bracket plates between the cylinder head and the frame. 0.096 inch thick sheet ti should be strong enough. They need to be bent. The 6Al4V structural ti alloy I usually use for machined parts does not form well. There is sheet in the commercially pure (CP) compositions that will form with no problem. CP Grade 4 is the strongest of them so the 0.096 sheet is ordered in this alloy.
The next project is to make a frame strengthening plate and a chain guard out of 0.125 inch thick ti. The metal needs to be strong and formable. Grade 38 is perfect for this. It is used for ballistic armor so if it stops bullets it can cope with the chain.
The last job is to make two lower engine mounting plates out of 0.200 inch thick ti. CP Grade 4 will be used for those.
There are several on-line sites that sell titanium bits. This is the one I use for everything except round stock.
https://tmstitanium.com/