Jetting Modded Briggs 5hp

#1
Hey guys, what size main jets and idle jets are you running on your modded Briggs 5hp FH's? Just so I can get an idea on where to start.

Thanks. :thumbsup:
 
#2
I assume your using gasoline? I currently have a #34 jet in my yellow Raptor 3. It seems to run very well with it, but its not a heavily modded engine. It has a Dyno 98-3 cam, ported intake port, and a shaved head. I believe the factory jet was a #30, but I can't remember for sure. Now if your running alky, your jet choices should start in the 50's. This is the place I got my jet from. 34 Briggs Raptor Jet Kit Go Kart Racing Parts Briggs Raptor Engine Flathead Jet | eBay

Matt
 
#4
Thanks Matt. What size would a #34 be? My motor has a milled head, ported intake, Dyno 94ss cam, stiffer springs, and a header.
The way jet sizing works is like this. a #100 jet would be 1.000mm, my #34 jet is .34mm. The #34 jet would require a #80 drill bit to achieve the .34mm if you wanted to drill the jet yourself. Here is a drill bit size chart. Jets R Us Drill size decimal equivalents
I think a 34 would be a good start for you, and if you pick up a set of numbered drill bits, you could make any size jet you want. you can buy a numbered drill bit set at Harbor Freight pretty cheap.

Matt
 
#5
Thanks Matt. I already have a numbered drill bit set from when I was working with clones, I've just never jetted a Briggs before. Thanks again.
 
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