aftermarket carb for my briggs

delray

Well-Known Member
#1
i been looking at some mikuni clone style carbs for my stock 5hp flathead briggs and was wondering if any you guys have done the the samething and what size carb has work the best for your "STOCK" engine. the only mod will be a header pipe exhaust system. for example a 19mm carb or something little bigger.
 
#2
Hey Delray,

I read your post and it reminded me of a recent build I read here of a John Deer themed Trike. I can't remember who the builder is atm, but I'm sure somebody else will know.
It featured a 5hp briggs with a mikuni type carb on it.

Sorry man.
 

gbabins1

Active Member
#4
Hey Delray,

I read your post and it reminded me of a recent build I read here of a John Deer themed Trike. I can't remember who the builder is atm, but I'm sure somebody else will know.
It featured a 5hp briggs with a mikuni type carb on it.

Sorry man.



I think that was KB2ROCKET that built that.....
 

delray

Well-Known Member
#6
jesse8931, have you tryed a 20mm on a stock briggs before? would that be the correct jeting for a stock briggs engine. also i will look up kb's build.......:thumbsup:
 
#7
Theres no such thing in the world as a Mikuni slide carb built for a Briggs 5 horse rototiller...:lol:

But yeah.. 20-ish millimeter (so the air passage is about right) will work pretty great on one... You're just gonna have to come up with a main jet that works to your liking.. Probably ABOUT any size you could want is available...

But I have noticed when way over jetted like with pre jetted carbs.. You can run a single fine piece of copper wire through the actual hole that IS your jet, and keep stacking one after another, effectively plugging the hole off, restricting fuel flow, and leaning out the carb.. :shifty:

But pretty well any 20 MM Slide carb is gonna go on like a 125 dirt bike and be DUMPING the main fuel to ya.. :laugh:

I would definitely not go over like 20 on a stock engine.. If you go bigger than it can handle at idle, it will be kinda sluggish to respond to throttle input.. It will cause ya to cough out under a massive dump or air when ya punch it wide open... A slightly restricted center bore will help it pull fuel at an idle speed, and allow ya to snap the rpms up faster, due to it has plenty of fuel mixed into the stream already....
 

delray

Well-Known Member
#8
kind of thinking the same thing too. a stock 20mm carb still got to flow and perform better then a factory briggs pulsajet carb:shrug:
 
#9

I found the receipt for this carb the other day,its a 21MM strange size but it works real good.I cleaned the ports on this engine and made the exhaust.I did rejet the main but I cant remember the size.They run really good with these carbs.
 

delray

Well-Known Member
#10
roccosbike,was that a stock 5hp motor you ran that carb on? if so i would like to really know the magic number for size carb(mm)and jet,so i am not going back and forth trying to figure out the correct carb...etc....
thanks........delray
 
#11
roccosbike,was that a stock 5hp motor you ran that carb on? if so i would like to really know the magic number for size carb(mm)and jet,so i am not going back and forth trying to figure out the correct carb...etc....
thanks........delray
Yes this is a bad dog motor,I just cleaned up the ports and put a Horstman head on it.Its a 21MM taper bore carb.I had to drill the original main jet a little to get it perfect and it needs the air filter to run right too.This is by far the best running Briggs engine I ever had.
 
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