Ideal race only exhaust - help for kart project

Hi guys,

I am going to be dropping an SV650 engine onto a kart and so I need to ask about exhaust mods and how the engine reacts to different exhausts.

Due to the routing of the OEM pipes (going under the bike) I won't be running stock headers - I might be able to use part of them but then have to go custom for the rest.

The kart will be obviously for race only, so I don't need to worry about noise - its going to be drag raced at Santapod so no noise limit on exhausts (which is good!)

I know as its an NA engine (at the moment...) I still need a bit of back pressure to correctly scavenge the cylinders of exhaust so I need advice on what people have found to be the ideal lenght/can/open pipe for the best performance gain.

I am guessing that OEM headers to stubby can will probably give me what I need, but I have seen some 'race bikes' with no rear can and just a cut off OEM exhaust.

I am aware that I will need to rejet the carbs etc when doing these mods, its in the plan to do that, I will also probably be running velocity stacks as well, also not having the whole bike in the way it should be eaiser to sync and balance the carbs!

What are peoples suggestions?

FUUUUUUUUUNNN!!!!

A Kart with that much power!? Leave the exhausts fully open and hear the roar, in fact aim it backwards towards all the other karts eating your fumes, scare'em off. Won't you be wheelspinning constantly??

A completely nooby and worthless answer I know, but I love the idea!

Think a lot of racers use the M4 setup?

Isn't this going to fluff up back pressure etc by not using the original routed headers? It's something I've never really understood why (the routing of exhausts) it's done the way it is. But surely there is a reason...

Good idea though. Will sound like something raising hell on track.

The reason behind the odd shape of the OEM headers would be to ensure the exhaust headers are equal lenght before they merge and go into the rear can, its a common issue on V twins due to the front cylinder having a longer route than the rear, the issue is I can't run OEM headers as I have no ground clearance to run it under the kart, might have to get some OEM header stubs and see my mate who custom fabricates exhaust lol