400ex-yzf 450 Could it be done?

[keepitpinned]

I just bought a 04 400ex. I was soo happy when i got it, thought the power was nice. Then today while riding i met these two guys who both own yzf450. I took a ride on one and was amazed by the power. makes my look so small in power. is it possible to have my 400ex run with stock and piped yzf. I dont want to bore ans stroke it to like a 465 or anything. i want to keep it as reliable as possible.

[toby400ex]

A good 440 with a full exhaust, cam porting and what not shouldnt have a prob hangin with them.

[outofsight]

A good 426 will take a yfz450.

[keepitpinned]

im prob getting the sparks 416. opinions of what you think bout it? what else should and need to get done to motor?

[seven]

I have a 426 with a 11to 1 piston, Sparks exhaust, Port job and a hotcam stage 2 and I can easily beat a stock YFZ and a piped one will only pull me by a quad length or 2. Dump about 600$ into the motor and she will fly!

[pnut420]

DO a YZ426 in a EX frame then you will get them for sure.

A built 426 is close, I would say with a FCr39mm, sparks, porting, 11:1, Rev kit, stage 2 hotcam you will be even with a stock YFZ450 and might take them on the downhill but be even on the uphill