Header tech

[anglia4]

This isn't strictly car related.

 

I'm building a new exhaust for my 4cyl honda CB650 motorbike.

 

What are the advantages of 4-2-1 or 4-1?

 

Cheers

[cute wee gem]

4-2-1 are meant to be better for mid range torque. 4-1 better up in the revs - supposedly.

[kpr]

old talk is, 4-2-1 should give a fatter power band since you have 2 tuning points.   4-1 should give more peak where ever you tune it to. 

 

but

 

it all depends how they are built.  primary diameter, length,  collection points for 4-2-1  etc. black art voodoo shit.

 

4-1 would be easier to get right

[Spencer]

Yup you will peaky race bikes and cars with 4-1 & 4-2-1, depending on required power delivery and a whole swag of other factors. As KPR has said some 4-1 headers will be the easiest place to start.

[bubblegoose]

4-1 for bikes, becasue space is a big factor to consider

 

and also low end power is for girls

[SOHC]

In all my time in being a motorcycle mechanic have I never come across a 4 cylinder bike with Try Y headers, some bikes have a 4 into 2 with a cross over pipe or a collector but if you want to make them faster you fit a 4 into 1 system  

 

 

 

There is a caluactor on the net some where for working out primary pipe size and length and 2ndry pipe size

[Spencer]

So 4-2-1 is no good on a bike because you haven't seen one? as I said plenty of race bikes and cars have 4-2-1 exhausts, but for mere humans the 4-1 will be easier to make work.

[SOHC]

I have 4-2-1 headers on my car, not saying they don't exist, I was talking about having a collector in front of the motor and long 2ndry pipes like a TRY-Y type on a inline 4 motorcycle motor

[Rookie]

You mean try ys on a motorcycle engine like these?

 

But I totally agree with the others, 4-1 is best for mere mortals.

[bubblegoose]

4into4

I agree^ do that

[SOHC]

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