port timings
-
tea5ive
- registered user
- Posts: 575
- Joined: Sat Mar 21, 2009 3:41 pm
- Main scooter: cometa 140
- Location: gilberdyke, east yorks
- Contact:
by taking 3mm (with 1mm gasket so 2mm) off the bottom of the cylinder
raise exhaust by 4.8mm gets 170.29
raise trans by 1.2mm gets 125.07
clean bottom of inlet and a bit of a rub with sum emery tape on inlet side of the piston gets 145.09.
will take the cylinder to work and machine it down. hope i have done me sums right
raise exhaust by 4.8mm gets 170.29
raise trans by 1.2mm gets 125.07
clean bottom of inlet and a bit of a rub with sum emery tape on inlet side of the piston gets 145.09.
will take the cylinder to work and machine it down. hope i have done me sums right
132 aint too high imo!
unless you intend to stroke it which would make them higher
unless you intend to stroke it which would make them higher
-
tea5ive
- registered user
- Posts: 575
- Joined: Sat Mar 21, 2009 3:41 pm
- Main scooter: cometa 140
- Location: gilberdyke, east yorks
- Contact:
i will be using a 60/107 crank as this what i have to hand and a 42mm ancillotti which i want to use, with the standard li125s gear box with 16 or 17/46.eden wrote:132 aint too high imo!
unless you intend to stroke it which would make them higher
so its132 with that crank?
just raise the exhaust port enough to give it some blowdown
-
Adam_Winstone
- registered user
- Posts: 1693
- Joined: Tue Jan 31, 2012 8:54 pm
- Main scooter: Lambretta GP
- Contact:
^... true but it'll then come on to what rev range he wants to run it at and whether the exhaust will allow it to get to the revs at which the porting works, otherwise it will be constantly out of the powerband 
did he say what exhaust he was using? I must admit I didn't read all of the 1st page of posts lol