all 400ex years (99-04) have the exact same part # for the carb. this makes me believe it is the EXACT same carb.

 

just check honda.com

 

Engine Type 397cc RFVC air-cooled dry-sump single-cylinder four-stroke "2003"

Bore and Stroke 85.0mm x 70.0mm

Carburetion 35.5mm piston-valve with accelerator pump

Ignition Solid-state CD with electronic advance

Starter Electric


DRIVE TRAIN


Clutch Manual

Transmission Five-speed

Driveline O-ring-sealed chain


CHASSIS / SUSPENSION / BRAKES


Front Suspension Independent double-wishbone with Showa shocks, five-position spring-preload adjustability; 8.2-inch travel

Rear Suspension Pro-Link fully adjustable single Showa shock; 9.1-inch travel

Front Brakes Dual hydraulic 174mm discs

Rear Brake Single 220mm disc

Front Tires 22 x 7-10 knobby radial

Rear Tires 20 x 10-9 knobby radial


"2004"
Engine Type 397cc RFVC air-cooled dry-sump single-cylinder four-stroke

Bore and Stroke 85.0mm x 70.0mm

Carburetion 38mm piston-valve with accelerator pump

Ignition Solid-state CD with electronic advance

Starter Electric


DRIVE TRAIN


Clutch Manual

Transmission Five-speed

Driveline O-ring-sealed chain


CHASSIS / SUSPENSION / BRAKES


Front Suspension Independent double-wishbone with Showa shocks, five-position spring-preload adjustability; 8.2-inch travel

Rear Suspension Pro-Link fully adjustable single Showa shock; 9.1-inch travel

Front Brakes Dual hydraulic 174mm discs

Rear Brake Single 220mm disc

Front Tires 22 x 7-10 knobby radial

Rear Tires 20 x 10-9 knobby radial

 

yeah, but most still agree it is a misprint. i have called my local dealerships and had them check on it. after getting back with me they both told me it was the same carb as previous years. who knows......

 

They didn't do anything to the 2004's. They are the exact same as the 99-03's. Yours might be faster because you have a fresh motor. There are no mechanical differences at all. The 38mm carb on the Honda website is a misprint.

 

do you have titanium valves or just titanium springs and retainers? if you do, where did you find Ti valves?

 

I did the same thing. I went to my local dealer and asked. they said it's the same 35.5 mm carb.

 

the 04 ds's are much faster than the previous years, and they shead like 20 pounds but it seems there's something in the engine, or the cdi that perked things up. and i wouldn't put it past honda to make a little change here and there to pass the others (suzuki) and not say a word. didn't i read the suzuki frame is almost the same as the 400ex frame just a mm here or there different. well i'm glad to hear the honda's are faster.

 

 

Lots' of times Honda and other OEM's will make small adjustments or improve a existing part that will radically improve a bikes performance with out changing the part number so as not to alarm the buyers. It can generate a recall or even worse hurt the residual sales of their ATVS.