I am looking at getting one of these kits for my 400ex 2001. I do most of my riding on wooded trails with dirt sand mixture. I do not what to change my pipe and would like to stay on premium pump gas. Is there a big increase in power? Where is the increase? Any one do any, before and after dyno test or even radars. Is it all that and what should I know before I buy. Is it worth with out the pipe?

Any help guys would be great.
Joe

 

I would estimate that a big bore kit will give you about half as much power as good cam will, atleast it did with my 2000 453 EX. I would highly recomend a midrange cam for what you are doing. The cam is about $150 but you will need your rocker arms re-angled by 15 degrees and hardwelded.This will cost about $200. Altogether for cam and labor maybe 400 -450. It cost me about $500 for the 453 kit which includs weisico piston and rings, LA Sleeve, cometic gaskets and all labor. I run 11:1 compression on 93 octane and have not had ANY overheating or reliability problems. I run only trails with it.

 

FAST453EX... Are you saying you think your cam added more HP than your big bore? I am just curious.

Also, is your sleeve tapered or did you have to have your cases bored for the sleeve to fit? 453 sounds pretty sweet I am getting a 440 made by SParks which I can also have bored to 465. What millimeter is your piston?

One of the guys I ride with has an IMS 440, WB race cam, and a big gun exhaust. We ride trails together alot and ride fast, but we also will cruise around and he doesnt seem to have trouble. He runs some really tall gearing I think the tallest Sidewinder has with stock tires and seems to pull it fine.

FAST I hope I am not annoying you with too many questions I am just curious about your bike sounds pretty sweet. I cant wait to get mine back it has been like almost a month since I sent my motor away so I need to hear about other people going fast.

Adam Smith

99 400EX

 

The cam definately makes more power than the big bore kit! My cylnder was bored to accomodate the bigger sleeve. The piston is bigger by .220 I beleive. I have had no problems with my motor and it's very reliable and trail ridden, I have 11:1 compression, porting and polishing, Web cam, no airbox lid, K&N and outerwear, 170 main, WB CDI and E-series exhaust with 12 discs, I love my EX-RIDE RED!-

 

453,

What do mean by the cam makes more power then the big bore kit. It doesn't make any sense, please explain. Why do the whole kit if the cam does more by it's self.

 

What I meant is that a cam alone will produce more power than a big bore kit alone, of course if money is no object get both of them for the maximun power increase.