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View Full Version : 400ex OEM CDI Box 99-04 vs 05-07


rdwelch
10-25-2007, 07:15 PM
I need some help from you 400ex experts... Will a CDI box from an '05 400ex plug in and work on an '04 400ex? Honda shows a different part number, but they look like they have the same architecture. Anyone have any experience or knowledge of this?(The reason I am asking is I have a chance to buy a CDI box from an 05 model for cheap, and my ride is an 04.)
oleboy87
10-25-2007, 07:21 PM
are they both stock cdi boxes? if so it does no good to replace because they are all the same on all the years
rdwelch
10-25-2007, 07:26 PM
Not looking to switch out, looking to buy an extra unit from an '05 to keep as a spare, since the price is right. So, is a CDI from an '05 the same as an '04, even though Honda has different part numbers?
oleboy87
10-25-2007, 07:55 PM
yep they are all the same...
00.400ex#55
10-25-2007, 08:43 PM
almost positive there not the same..
oleboy87
10-25-2007, 09:12 PM
well i could be wrong... lol if i am im sorry for giving false info rdwelch
Big - D Racing
10-26-2007, 01:25 AM
they are not the same!!!!!!!! The 05-08 have reverse's. The cdi includes mapping and a rev limiter for when the quad is in reverse. I also believe the internal transmission gearing is different and the cdi is mapped different for those gears. I would not run a newer cdi on an older 400ex. Who know's how it will act, if it start at all, and the potential engine damage it may be able to do. Not saying it will but I wouldn't risk it.
slow96hater
10-26-2007, 09:14 PM
im with big d.
JOEX
10-26-2007, 09:28 PM
Who wants to nut up and be the guinea pig?:p
rdwelch
10-27-2007, 07:06 AM
OK Fellas... thanks for all the input. Now, I know most of you are ATV riders, but here is one more curve ball for you... :)

I recently converted my XR400 over to electric start by installing a crankshaft, flywheel, stator, CDI box and rectifier from a 400EX. Works perfect, but I am wondering if I should be aware of any differences between the XR400 CDI box mapping and the 400EX CDI box mapping... I know the cams are slightly different in the two motors... Any thoughts out there? Thanks in advance.
Big - D Racing
10-27-2007, 01:11 PM
I don't believe any of the internal parts are different besides what you swapped the kick start for the electric. I think the cdi's are the same.
espergre
11-13-2007, 10:37 AM
I know this thread died and is prolly over, but.. an 05-07 cdi box will not work with a 99-04 engine. It needs input from the reverse loop proving it is not in reverse to start. 99-04 quads dont have reverse so cdi will not give spark. I tried moving my white bros cdi from my 99 to my 07, it works fine. but the 07' cdi would not start 99'