Hi all,


I work in an engineering shop and was gonna make myself an exhaust system for my '00 KLX300. Just wondering if anyone has some ideas on header muffler sizes that I should use or others are running. Any info would be appreciated. Thanks

 

I would think a pipe with the inner diameter matching the exhaust port would work the best. I know of a few people who have ground out the stock header to match the port size, and had good results. You might also consider the powerbomb setup style, with an expansion section placed just after the bend and filled with steel wool, supposed to free up a little more power. I run a full Delta exhaust here in Japan, it is the smae size as the outlet port, and seems to work very well, although it is a little louder than most, even with a baffle placed at the end of the muffler.

 

I just went out and measured Big Guns Header. It is 1.5" OD Tubing with .03" Wall.
Hope that helps.

 

Thanks for the info so far.

What is the size of your mufflers? usual 4" diameter? but how long is it? Also what size is the outlet on the muffler?

 

Feedback from people on the forum say the larger diameter of the full exhaust systems gives the bike better high rpm HP than stock, and a bit better low end torque
The slip on's with the stock header report better torque in the lower end, and a bit better hp in the high end rpm
So basically if you like to lug the bike around, stay near the stock header size, and for high revving power, make the header larger like the BG
That is my suggestion

 

Why don't you experiment and fab' up a "drooper" style header ala KLX450R.

 

with that header, i bet that bike makes killer torque.

 

That's what I've heard. Local guys are swapping the headers on the KLX450F and the CRF450R for the header off the enduro model for (KLX45R & CRF450X) the more friendly spread of power and better bottom end.

 

Are you planning on marketing the exhaust or is it for personal use?

 

Only for personal use. Ive made a bash plate for it so far and thought the exhaust was something I could easily fabricate also. I have no intension to sell it.