69cc header inner diameter

[gary55]

you'd have a heart attack if you saw my drag racing engine. she pegs out the compression tester

How high does your gauge go to? Mine goes to 300. That would be over 20:1 and need around a 2.5cc head to get there.

 

[gary55]

OK wait a sec. I just figured out I'm a idiot,,,again! Your not talking about a motorized bike, duh. So does it even need a spark plug?

 

[Deleted member 12676]

a drag race is for a short amount of time

 

[butre]

How high does your gauge go to? Mine goes to 300. That would be over 20:1 and need around a 2.5cc head to get there.

all the newer ones go to 300, but mine's older than me so it only goes to 200. it's probably in the 235-ish PSI range with the 4.3cc head

 

[gary55]

all the newer ones go to 300, but mine's older than me so it only goes to 200. it's probably in the 235-ish PSI range with the 4.3cc head

Sweeeeet. That's gota be fun.

 

[butre]

it is, but as always it needs more. I'm in the process of going to a 56mm bore. lot of nickel and dime stuff to deal with currently, like brakes and gearing and finding screws I like and finding some particular tools to finish it, but I'd like to see it on blacktop by next month. if it'll run 9s in the eighth I'll be happy

 

[zippinaround]

ok so on a stock exhaust header diameter measures 17.8mm i also measured a 9.2hp 49cc water cooled header i have that was 24.85mm . on the first pipe i made for my 48cc i used 16.5mm and it worked pretty well. and a stock mini moto header is 20mm