Check this out Pick Here That 52hp 400ex is a 473cc beast....like the page says, strongest tested too date. You can guarantee LS at GT thunder makes a lotta 40+ hp engines, buy they are not a stock 400ex engines with a standard 440 kit and a cam and pipe. No-matter what guys say.....anything over 40hp does'nt come easy on the 400ex. THat 52hp engine would probably cost as much as a Cannibal.

 

lateapex (good nickname, BTW) and Gary, you guys are correct.

Sometimes terms like "VERY" "EASY" "SMOKED" etc get thrown around too easily.

I for one am VERY impressed with how EASY it was to get hp out of the Z400, no doubt it will SMOKE a lot of other machines when fully modified. [img]i/expressions/face-icon-small-smile.gif[/img]

One thing though, a 400ex and Z400 have similar displacement so the theoretical limit should be the same; it's just that the Z400 seems to have a BIG headstart right out of the box.

 

wyoduner, both machines are 400's, but the z400 uses liquid cooling, dohc, and is more oversquare. this all results in a motor that can produce more power at higher rpm's. also, the z400 has a greater overbore capacity than the 400ex. the limit for the 400ex is 450cc without stroking, the limit for the z400 is 470cc without stroking. as far as the potential of these motors go, just look at the gncc bike series. the dominant 4strokes are the wr426 and the drz400e, you hardly ever see an xr400 anymore.

 

Wow.....470cc huh? Looks like over 500cc for a Z will be a good possibility. When is resleaving required?

 

gary, the z400 doesn't use a sleeve, it uses a nikasil cylinder coating, so any boring at all will require the motor to be either re-nikasiled or re-sleeved. the 470 kit is supposed to put out tons of tourqe, but it doesn't rev as fast as some other kits. in my opinion the best kit is the one that Mike K runs in the gncc bike series. it is composed of a 436 big bore kit, head porting, yoshimura rev kit(cdi, cams, valve springs), yoshimura ti exhuast, modified stock carb, and aftermarket filter and airbox. this combo will pull hard on wr426's. with this kit the motor puts out a over 50 horse and revs out to 11,500 rpm.

 

Anybody know how much that 40mm carb kit costs?