Can I change my head from 2 valve to 4 valve. Piaggio

[mj]

I have a Piaggio Fly 50.  Instead of a big bore, I want to install a Piaggio 100 cylinder (both bottoms are the same).  It appears (from schematics) that the only difference is that the Fly 100 is 2 valve.  Both cylinders look identical in photos.  Can I install my 4 valve head on the  Fly 100  cylinder?

I will also upgrade to a larger carb.

Thanks in advance

[jeff84]

the head studs and timing chain have to be replaced as well. they are longer on the 4 valve heads. otherwise the bottom end is the same.

[jeff84]

you cant use the 2 valve cam in the 4 valve head either obviously

[jeff84]

also the spark plug boot will have to be replaced the regular boot is too big around to grip the tiny plug, and too short to reach it.

[mj]

Hey Jeff84,

Thanks for the reply. The timing chain,bolts and cam gear are the same parts numbers. It seems that I might be able to just replace the 2 valve head with the 4 valve head. What are your thoughts?

ty

[jeff84]

if the part numbers are the same then the parts are the same. the parts I listed were different when I combined a 50cc 2v motor and a 50cc 4v motor.

[mj]

UPDATE:

It looks like all the parts are the same except for the actual piston. 2 valve and 4 valve pistons have different shaped tops. Because they don't make the 100 cc in a 4-valve model, I can't find a 4 valve piston in that size.

[pinkscoot]

You may need to grind your own valve reliefs in the piston.