I would like to mod my 400ex a bit more so that I'd be able to hang much easier with 450rs. I'm looking to quiet it down a bit as I have a DG pipe and it is VERY loud (it's a slip on). It also has a K&N Air Filter and the engine is ported. I'm thinking of getting a much better exhaust system. Should I go for an FMF exhaust system (I hear that the FMF headers really improve bottom end)?

With the mods that I have (plus a 14T front sprocket), I was able to stay beside a 450r on takeoff but after 2nd gear he was pulling away. Would a better clutch (Barnett perhaps?) improve performance a lot? I'm listening to suggestions. I'm not really interested in a 416 or 440 at the moment though...

 

get a rev-box, they are well worth the money!!!!! you can get 2 types either the preset which i have and love( gives you 3+ hp, extra 1100 rpm's and better spark) or the adjustable which allows you to set up your own curves for different exauhst motori set ect., littl emore on the expensive side though.

 

Is the rev box easy to install? Would an extra 1100 RPM be too much into redline?

 

It is very easy to install it would take you maybe ten minutes you can pick up a scimatic of where it's located at your local dealer, it will not hurt your machine just improve the performance, as long as you dont constatly red-line your machine which is obviously bad if machine is modded or stock. but i love mine and it lets me hill shoot much faster along with my 14 tooth front srpocket.

 

Maybe I should go for the custom rev box. I'm used to a stock rev limit so I do not worry about holding the bike in full throttle in 5th. I guess even with an extra 1100 RPM and a 14T front sprocket, it probably won't redline in 5th though right?

 

Here is my list of mods - let me know if you have any questions ....

1) Duncan Racing 440 Kit
2) Powroll 4Mil stroker
3) Race Head - Ported with 1mm oversize WEB valves - Hardened rockers
4) JE 12:1 Piston
5) Web Cam
6) Edelbrock 38MM "Doug Eichner" Carburetor
7) Motion Pro Twist Throttle
8) Hinson Clutch Basket
9) Duncan +1 clutch kit with Extra Clutch Plate Side Case and quick change cover.
10) Barnett Clutch Springs
11) BOSS NOSS 25hp shot of Nitrous
12) LTE Dual Exhaust
13) Lightened Flywheel
14) HD Stay Bolts
15) ACE Oversize Oil Tank/Cooler

I think thats all of the motor mods. She rips.

 

A rev box will shorten your engine life if you take advantage of what it gives you. No two ways about it. I hate fake power. See how that guy up there^ has an excessively hooked up quad, but no rev box? Think there's a reason?

 

From what to what? The EX is the most durable motor I have seen. A rev box is just about as insigificant of a reliability reducer of any part available. Now, that being said, if you have a bad one, from a bad manufacturer, they can be bad. But Big Gun, Vortex and others I have used - I dont believe they will reduce your engine life a bit.

JMHO based on years of experience.

PS - That guy up there is running NOS, and does indeed have an aftermarket CDI box with stock curve and 1000 raised rev limit. For NOS, its the way to go. Without NOS, a slightly advanced curve with a little rev limit being raised is good. You wont get anymore than 1-2 HP gain. But the acceration will be better and it may help with your shift points with the raised rev limit.

 

I didn't say it would blow up your engine, I said it would shorten it's life. If you think that moving your engine parts faster somehow doesn't effect ring and bearing wear, you're wrong. And an exhaust system will shorten it's life more? C'mon... People who buy rev boxes use them! There's a reason Honda didn't just tack an extra 1100 onto the redline from the get-go. (Didn't know you had a box, and I donno if you're the one to talk to about engine life Mr. Shots-of-NOS)[img]i/expressions/face-icon-small-tongue.gif[/img]

 

How old are you? Jimmy?

Let me know if you want to compare credentials - I'd be happy to share with you anytime. I do know about shortening engine life, A rev box is truely insignificant. Yes, there are things that are, but this discussion of yours is about the silliest thing I've heard of in a long time - Actually, you made my day. LOL