building a honda gx340

[93notch408]

im wanting to build my honda gx340 motor for my drag frame i dont want it to be super serious but would like some power out of it

my plans are...

aluminum rod
aluminum flywheel
rockers
cam
mikuni carb
nice stage header
70 thou milled off the head /port polish work

what size carb do u guys think i should run with this setup i dont wanna get to small or too big of a carb

 

[MIModMini528]

Depends what size intake valve your going with...

 

[Stangrcr1]

I have a TM32-1 flatslide Mikuni on my 390 and it may be a bit big for my torque cam. I would consider a CVK style off a streetbike in the 28 range if I was to do it over for better rideability. For drag only, the flatslide works well.

If you are changing the valves, watch the valve length as this will change the geometry and require longer pushrods, and rocker shimming, even with the head milled.

 

[93notch408]

i might stick with stock sized valves thx guys

 

[65ShelbyClone]

It also depends on how much cam you're using, how high the engine will spin, how much power it makes, etc.

I'm probably going to try a 34mm Lectron on my 340 if for no other reasons than I already have the carb and it will provide a little overhead. I also have a 38mm throttle body to use if the EFI bug bites again.