powerbomb.... moto.... sx.. whats the difference

[yamahasocal450]

ok well ive decided on the titanium powebomb header, now when i order it it says moto or sx.. whats the difference between the 2 ... is this a stupid question ?

[dominator426]

Compared to the regular 'moto' configuration, the 'SX' (supercross) header has smaller diameter tubing before the bulge, matched to the exhaust port, to increase low and mid range power by increasing back pressure at exhaust port.

[yamahasocal450]

so do you think i should get the moto or sx, more low range sounds great because im going to get the yz camshaft soon but i dont want to cut out too much up top thanks ?

[MiniMadMan50]

I have the moto on my 250F, and it REALLY comes to life up top. Is this going to be on your wr450? If I was you, I would go with the SX for the low end. Not that these big bore really lack in either department, but if anything I would want more low end. Then get your jetting dialed in. Once I went to a leaner mainjet on my 426, the power up top came to life. With your new pipe and excellent jetting, seems to me like you will be able to achieve the best of both worlds ?