400 compared to 450?

[redexrider4290]

i am thinking of buying a new bike soon i am looking for either a 400ex or a 450r

this past weekend me and some of my freinds were riding together and my one freind just got a 06yfz450 (stock) and my other has a kfx400 (slip on pipe, airbox lid removed,jets,1tooth bigger front sprocket) and they raced on this road the first race the yfz won by about a bike length then the next race the kfx won about half a bike lenght

well i was surprised how close they really were

well anyway i was wandering how would a 400ex with some mods like k&n,pipe,jets,cam,and posibly a small bore like a 416 compare to a 450 or the kfx listed above how would they compare in power? acceleration?speed?

and how would a moded 400ex(mods like the one above) compare to a stock 400ex

thanks guys
sorry if im asking to many questions

[northwest Texas]

To answer your questions. First, depending on the mods, the modded EX can toast the stock one. The EX will always be just a tick behind the newer gen such as the 450's and even the Suzuki 400. Not that it can't compete though.

If you've got more money to spend than I and are buying new, then I guess it's your call.

I would buy a used 400EX for the low $2k range. Unless you're only interested in drag racing (then you wouldn't be looking for an EX), chassis mods i.e. aftermarket shocks, wider width, etc. will make it faster than engine mods.

When I bought mine, I decided to spend the money first on good suspension and making the chassis handle well and easy to ride. I wanted to ride it, not the other way around. I am completely satisfied I went the right direction. I can't imagine having my engine in a stock chassis i.e. stock shocks, stock width, stock bars, etc. And I didn't have any complaints with the stock handling until I started modding it and found out how much better it could be.

If you're riding trails and such, no organized racing, you can beat your buddies with their stock chassis on the trails with better suspension.

I've said this before and I'll say it again. My engine never really felt slow until my chassis could handle more than the engine could generate. Sure, I'd lose most drag races but that wasn't important to me. I'd rather ride fast down the trails with little energy being disposed by me than win every drag race and getting beat up by the quad on every rough trail.

[ohsobad_chevy]

Originally posted by northwest Texas
.........
I've said this before and I'll say it again. My engine never really felt slow until my chassis could handle more than the engine could generate. Sure, I'd lose most drag races but that wasn't important to me. I'd rather ride fast down the trails with little energy being disposed by me than win every drag race and getting beat up by the quad on every rough trail.

Well said. :cool:

[deathman53]

I work on the chassis first, then the motor. Too many do it the other way around and then instead of upgradig the chassis, they want a better motor. A guy on a lobo 2 chassis and nearly stock 250r motor, only a fmf pipe, won the class(I forgot, but lots of 250r's and 450's) at e-town about 3 years ago. This says alot. When I built my bikes, the chassis came first and build the motor to suit the chassis afterwards. Buying shocks, axle, a-arms may not seam like the smart thing to do over buying exhaust, carb, motor mods, etc, but you can go faster longer and with more controll with the chassis stuff first.