Fast and dangerous

[Luke135]

Home built briggs raptor with all good parts inside including tbr3 cam, ported 3 stage exhaust and mikuni. Cat 250 frame and 3500 stall spring in clutch. I run it on 93 octane with gold label blendzall. Exhaust smells like a indy car. Gotta lean way forward when on the gas or you'll be on your ass in a heartbeat. Clocked at 63mph with more to go.
I used to race ama flatrack. I like fast bikes.

 

[Triley41395]

Clocked at 63mph with more to go.

WHAT...DON'T LET UP TILL YOU SEE JESUS.
Nice build, too fast for me on small tires.

 

[f4radar]

I like it.

 

[bikesisbikes]

You're getting 63 MPH with a very restrictive lawnmower, spark suppressor muffler and plumbing pipe, for an exhaust? What would happen if you opened up the exhaust to match the intake?

 

[Luke135]

The exhaust is a design from a karting forum. 3/4" 4" long coming out of the port into a 4" section of 1" into the muffler which is from a 12hp briggs which has been gutted. Is a design which has been dynoed and adds 3 to 4 hp on a modified engine.

 

[Sunnyknoll]

63 MPH? I must be a "Woos". I can still remember looking for toilet paper at about 30. (ha)

 

[bikesisbikes]

The exhaust is a design from a karting forum. 3/4" 4" long coming out of the port into a 4" section of 1" into the muffler which is from a 12hp briggs which has been gutted. Is a design which has been dynoed and adds 3 to 4 hp on a modified engine.

Now that's some good info. I'll have to look that up.

 

[massacre]

Briggs flatheads love 3 stage exhaust

 

[bikesisbikes]

Briggs flatheads love 3 stage exhaust

That I have read. And I run a 1/2 inch drill bit through the spark aresstor blockage, on the end of header mufflers. I was just surprised to hear cast pipe, does so well. A tuned header, I understand. Cast pipe, not so much.