www.zxrworld.co.uk

hi guys ive been building a zxr400 race bikeive got ram air higher lift cams standard carbs not flatslides dynojeted ported head but ive stil got a standard ex system with a pro can,wot i want to no is wot exhaust-headers to build 4-2-1? 4-1? 1 1/4 primaries or 1 1/2 tapered headers or not does any one hav a measurement or no wots best? im racing in new zealand thanks in advance

Hi there,

I race a ZXR 400, pretty standard as the rules governing Production racing in Scotland do not allow for much.
4-2-1 is fairly the norm with Micron doing a complete race system that is not too costly (we are in Scotland) and performs well on the dyno. Keep your eye out for 'Trick' systems occasionally found on Jap imports. Top quality builds and tuned for this specific model. Flat side carbs, SP cam and a good quality system should get the best out of the bike while remaining reliable. Not that I can speak blew mine at Knockhill track last weekend!

Keep in nailed!!!!

i run the micron system , but modified it as it had poor ground clearance.

when we cut into the 2:1 section, we found a ridiculous 'step' where the prebaffles are, so we fabricated a complete new section with smoother lines.

made a much better shape to the upper end of the power curve from around 9000 up to the redline.

drew857 wrote:Hi there,

I race a ZXR 400, pretty standard as the rules governing Production racing in Scotland do not allow for much.
4-2-1 is fairly the norm with Micron doing a complete race system that is not too costly (we are in Scotland) and performs well on the dyno. Keep your eye out for 'Trick' systems occasionally found on Jap imports. Top quality builds and tuned for this specific model. Flat side carbs, SP cam and a good quality system should get the best out of the bike while remaining reliable. Not that I can speak blew mine at Knockhill track last weekend!

Keep in nailed!!!!

Drew, I beleive KHill is starting to allow formula bike out as well know?

I lurve East Fortune and theres no point in running a proddie bike around there as 40 formula bikes will go flying by ............. and again before the race is over.

Ayways back on topic.

Headers are the vital compoment on getting good zorst power - have a look at Mercury ones (Mercury bods were involved with Swona before it closed down)

http://www.mercuryraceexhausts.co.uk/index.html