Everybody is talking about how far to go, 400EX out 505?? 300EX to 370? Wow, its really not worth it. I put a big bore in mine to try it out and because I needed a new top end and it was only 100 extra. Power inprovement was minimal. It was hardley even noticale gaining 56 cc's, only a little more bottom end torque which does no good when you want to drag race or top out. MY advice is stick with stock bore and stroke. Go up on your compression and cam it, it will fly. I run even with my buddies EX that has the same pipe as me with a K&N power kit, stock bore 11:1 piston and a cam. I can't beat him even though I have a lot more mods and yes my jetting is perfect, I 've played with it tons and now its just right. Bore bores are good to brag about but when it comes time to race you may be dis appointed, the stock bore JE 11:1 piston is much lighter than a 440 piston so it will rev quicker and higher, so save your money, don't bore em out. Somethimes bored out motors get hot and vibrate more too.

 

Amen, well put.

 

Fast453, what happened man? What has brought this epiphany to you. I dont understand how you have come to this point. From what I remember in your previous post you loved your big bore. Honestly, this is the first time I think I have seen anybody bad mouthing their own big bores.

I have heard people with 416s theorize as to how their 416s could be faster than a big bore 400EX. I dont necessarily agree with their theories, but since I have yet to get my 440 back yet I will not offer any opinion on the subject.

Seriously, does anyone else who actually has a big bore feel the same way as Fast453EX? I think if this is really how Fast453EX feels it is good of him to share it with the others. I think it is good for us to all share our good decisions and bad alike.

Adam Smith

99 400EX

 

Could your exhaust be a weak link in your system? Maybe a freer flowing exhaust like a yoshi or DMC would help. Just a thought.

 

The big bore kit helped a little but I credit that mainly to the higher compression. It runs good though and will stand right up in fifth! The cam made a HUGE difference, that was my best mod, by far. But it runs good, just don'tm waste 5 or 6 hundred just for a few cc's, there are better choices, oh and I like the WB silencer and headpipe, I think it flows plenty.

 

Well, I hate to burst your bubble, but I rode a 440EX yesterday that had the higher compression piston and a greydon exhaust. It didn't feel that fast, but when drag raced, it beat piped banshees. The power was very smooth and seemless from bottom to top end. I think the head was also ported.

 

Oh I can blow away banshees too. I can beat a stocker on blacktop and piped ones aren't even close on grass or dirt. Its all about traction and EX's have plenty of it. But I can beat some banshees and a raptor once. My porting and polishing was helpful too.

 

If you had an aftermarket carb, you wouldn't have said those things. If you would have a lecrton or a FCR your power problems would be over. Most engine builders suggest a bigger carb for the most modified engines. I was at the same point as you until I got my Lectron, it made a world of difference.

 

hey fellas,
when you guys say *beat banshees* what do you guys mean?
I can take a banshee on from the start to at least the 100 ft mark where they are eating my dust (traction!) but after that, the get me by at least 6 lengths on me and my motor internals are stock.

rayz400ex
Honda 400EX RIDERS site:
http://home.elp.rr.com/hipo/atv/

 

I mean 1/8 mile 660 ft dirt drags where I can beat mod banshees because they can't hook up. Yes, maybe a carb is my weak link! How are the Edelbrocks?