OK guys, right now my 400ex has a DMC full exhaust, 11:1 lightened Ross racing piston with XR 400 head gasket, 450/451 Web-cam, and a Lectron carb with a k@n filter and entire airbox removed. It rips right now, but will porting the head give me better gains with the mods i have? I don't want to lose to much more low end though, considering that i already lost a bit with my cam and carb. Who does good porting for 4-strokes, and what kind of prices will i be looking at?

 

Get it ported. GT Thunder or Pro-Fab would be a couple of good Midwest choices. By the way, how did you end up with a Ross piston? I've got one too set-up at 11.5:1 by CT. It was a b!!!! to get in!! Did you have any problems?

 

Hey TRX440. I was looking on CT's website and their 400ex sounded impressive. So i called them up and talked to Allen. I asked him what he had for pistons in stock. He said he had Wiseco and Ross, but said the Ross was far superior. So i ordered the 87mm ross. It took about a month to get to me and when i opened the package they sent me the wrong size(stock 85mm). I said the hell with it and just put the 85mm in it. I wanted to ride!! I did all the work myself, and I didn't have any problems at all. What did you have trouble with? Did you set the ring end gaps? What kind of piston skirt clearance did you run? Did you get your head ported at the same time as your other mods? What did you pay for your porting?

 

I HAVE THE DMC EXHAUST, 12:1 COMP...CAM, PORTED HEAD, AND DOME...PRO FAB DID MY WORK AND I COULDNT BE HAPPIER...I GOT THE 426CC KIT TOO.....

 

How high of octane are you running with 12:1 compression Bubbag? How much low end did you loose with your mods?