Installation of a 44 big bore kit in 06 honda trx 400

[06_hondatrx_400]

I have a few Question that i would like some advise on. I plan on putting a 440 big bore kit in my 06 honda trx 400ex. The 4 wheeler right now has k&n, stage 2 hot cam, fmf slip on exhaust, amr rev liminator and fmf jet kit. Now my first question is when i put this kit in would anyone recamend port and polishing the head. Do i need to do anything with the valves or can i go without? Do i need to put on aftermarket headers or will the slip on be just fine? Also the compression ratio is going to be 11 to 1 would i need to run a higher octain fuel or not? Any other advice or recamendations would be appreciated. Thanks for your time and help.

[headache]

i would definetly buy a good exhaust header to go with the bigbore kit. 11:1 to would you will need a mix of race and pump fuel to be safe. getting the head reworked is a good idea too, but maybe not a must as long as everything was fine before you tore it down. maybe some upgraded valve springs would be good at the least. the rest of your mods are fine...

[tayyo789]

HD head studs from GT Thunder, and a quality head gasket....trust me

[06_hondatrx_400]

Tayyo789 do u think that i would need to get aftermarket headers or not.

[tayyo789]

i didnt, but im sure it wouldnt be a waste of money. the stockers are pretty small

[06_hondatrx_400]

Okay, thats for the help man.

[fmftrx300ex]

i definitly recomend a new header and with 11-1 on a 400 u might be able to get away with 93 but ur better blending with race gass to around 105 and port works a great idea especialy with a cam and big bore seein as ur flowing more in and out