400EX vs. 450r dyno

[CRE Performance]

Just food for thought....but I have a freshly built 400EX that I finished on my dyno today. It has an 11:1 JE piston, 426, Hotcams stage 2, fresh valves and a 5 angle valve job with no other head work (well, I polished the chamber and unshrouded the valves a bit, took 20 mins). I decided to compare it to an 05 450r with about 90 hours on it, hotcams stg 2, 07 silencer, open airbox and jetting. Heres what I came up with when comparing.......

The 400 made 1 more hp! The #2 bike is the 400, also noted by the slight squiggle at the first of the power curve.

Also, pay no mind to the overall numbers...this is a true torque measuring eddy current dyno, not an inertia dyno. Compared to other dynos, mine usually sits at about 7 HP less. Also a stock 05 450R makes 26-27 HP on mine. Final run I made on it today went 34 HP for the lil 426.

[Miami_Vice454]

Is the 450r stock or does it have hotcam stage 2 and other things you said, cause thats not stock :huh

[CRE Performance]

Sorry, went back and edited it...I can see how misleading that was:D Yes, the 450 has a HC2, 07 stock silencer, open airbox, dyno'd and properly jetted.

Reason I posted this here was I always here a lot of people talking about how "They should have just started with a 450", and I though that this was a pretty impressive and fairly cheap upgrade/build and it will indeed run with a 450. My dyno has dragstrip capabilites, with full tree, and can give you run times within .1 of a second accuracy and the two bikes strip times where almost identical.

Just thought my findings were rather interesting because I havent modded a 400 EX in ages.

[Miami_Vice454]

thank you for posting this now i can show proof to my friends that think their 450 are so fast. do you think a 450r with filter, full pipe and jetted is making that much HP? im sure the cam opens it up pretty nice. and why does it have a 07 stock silencer? is there a difference between it and 05?

[jasonwayne222]

I have a 400ex with the same mods except i got a wiseco piston, and my buddy has a 450r with the same mods as the one listed with a different slip on. So the power that me and my friends bikes are putting out should be really close to your dyno findings and let me tell you, I understand what numbers you got, not trying to say your findings are wrong but, the 450r still has way more power and torque, it will still pull away from me in any situation, ya i hang with him no problem but its still the faster and stronger bike, so in reality those numbers dont mean a hole lot.

[jasonwayne222]

Im sorry the only difference in my ex is i have a 416, but the 1mm bigger bore doesnt make that much of a difference,plus im jetted with open air box.

[coryatver]

why do you have an 07 silencer on a 05 450r? I don't think they even fit? I am betting the 400ex doesn't have a stock exhuast. Quit choking the 450r and put a aftermarket exhaust on it and it will probley jump off the dyno

[CRE Performance]

For the first question...the silencer from an 06-up 450R is far better than the one on the 04-05. Granted, the 05 headpipe doesnt flow very well, but it will flow more than the 05 silencer can handle, but not the straight through design of the 07. Yes, the 07 will fit, regardless of all the internet misinformation, its the head pipes that dont interchange between the two without a bit of strong arming.

As far as the number comparisons between the two, they were both on the same dyno tires and the same scenario so it really was a good comparison. And Ive heard 100 times that the 400's wont roll anywhere close to a stock 450, thats why I posted it. Dyno numbers may not tell the entire story, but the dragstrip pulls that this dyno is able to do does......and as stated before, the 1/8 mile times were very similar. The 400 went 8.92 I believe and the 450 in question ran 8.94 in the 1/8.

I own two 450s, a built 05 with porting, + 3 stroker, 13.5:1, CRF cam, WB full exhaust, open airbox ect.... And I also have an 07 used for XC racing with an HRC cam and pipe, motoworks slip-on and other odds and ends. After riding the 400 today, I know for a fact it wont run with either of mine....but the "closer to stock" 05 is a different story. I was really suprised at the outcome of the dyno pulls. The biggest difference I can tell in the power of the two in the graph is the over-rev of the 450 keeping you off the limiter.