So I wanted to either make this bore as fast as it can be, or throw a kit on the bike.
Awhile back I did most of this porting, drilled aux ports and did crazy finger ports under the exh and for boosts, etc.
Decked 3mm, ex timing is going to be somewhere in the 190s-200.
What I was missing before this round of porting was top end rpm.
Pulled insane thru about 10-10.5k then just fell on its face.
So I made the aux ports larger and increased the diameter of the ports and tubes themselves from about 3/16in to 1/4+. Sadly, I punched thru to the outer wall as there's not much meat there, so a little brazing was needed as the stud holes in the cyl are not enclosed (if enclosed I wouldn't have had to add material)
I raised exh timing by accident as one aux went to about 20.5mm in a lil spot, the rest is around 21.5mm. I don't think it'll be a big deal.
The bridges are a lil thin, but they don't take as much abuse as one middle ex bridge so I'm gonna add a lil relief in the cyl wall there to account for expansion with heat so the piston doesn't get marred.
I might have to add stuffing to this cyl as I chopped off a bit too much of the cyl skirt years ago not knowing that on a 50 the case stuffing is super important for throttle response compared to a 70.
if I knew that I wouldn't have chopped any of it. I'll just add some pseudo skirt with brazing strictly adding as a case stuffer, no piston wall riding on anything if I have s hard time wicking up.
First moped porting in awhile.
Excited to either rip or have it explode.