400EX CDI trick - Page 2 - Honda ATV Forum
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post #11 of 33 (permalink) Old 07-25-2011, 03:16 PM Thread Starter
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Quote:
Originally Posted by Reece616 View Post
would this be beneficial to a quad with just an upgraded air filter and exhaust?
It can't hurt. and a lot cheaper than an aftermarket CDI

"MOOSE WAGON "
00 TRX400EX aka "MOOSE ROCKET"
91 TRX250X aka "MOOSE WAGON" RETIRED
96 Polaris 400L sport (Mrs. Moose Ride)
07 Suzuki LTZ250 (Sons)
96 Polaris 250 Trail Blazer (daughters)
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post #12 of 33 (permalink) Old 07-25-2011, 03:39 PM
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haha alright...

i just ordered one on ebay for $20 haha

2006 TRX400ex
AC Nerfs - Swingarm Skid + Honda Racing Skid - Protaper Contour Bars - Rox 2" Riser - CBR Clutch Perch - Oury Grips - HT Moto Seat Cover - Custom Poly Case Saver - TRX450R Front Shocks - XR250R CDI - YFZ 450 Dual Piston Front Calipers - ITP T9 Baja Rear + GBC X-Rex - CanAm DS450 Front Rims +Holeshot SR Front - Dominator Bumper - UNI Filter - 13/39 Gearing - DID x-ring Chain

2004 TRX250EX
AC Racing Nerfs - Oury Grips - Fmf Slip-on - Uni Filter - Razr Rears
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post #13 of 33 (permalink) Old 07-25-2011, 05:42 PM Thread Starter
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cool deal you're the guinea pig just so you know Let us know how it works out.

"MOOSE WAGON "
00 TRX400EX aka "MOOSE ROCKET"
91 TRX250X aka "MOOSE WAGON" RETIRED
96 Polaris 400L sport (Mrs. Moose Ride)
07 Suzuki LTZ250 (Sons)
96 Polaris 250 Trail Blazer (daughters)
06 TRX450ER aka === Under construction

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post #14 of 33 (permalink) Old 07-25-2011, 08:05 PM
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definitely will do!

2006 TRX400ex
AC Nerfs - Swingarm Skid + Honda Racing Skid - Protaper Contour Bars - Rox 2" Riser - CBR Clutch Perch - Oury Grips - HT Moto Seat Cover - Custom Poly Case Saver - TRX450R Front Shocks - XR250R CDI - YFZ 450 Dual Piston Front Calipers - ITP T9 Baja Rear + GBC X-Rex - CanAm DS450 Front Rims +Holeshot SR Front - Dominator Bumper - UNI Filter - 13/39 Gearing - DID x-ring Chain

2004 TRX250EX
AC Racing Nerfs - Oury Grips - Fmf Slip-on - Uni Filter - Razr Rears
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post #15 of 33 (permalink) Old 07-26-2011, 11:10 PM
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the thing about this is that the used xr250r cdi box cost the same as a brand new stage3 from amr. and those are ebay prices.. iI don't know bout anyone else but I would rather go brand new aftermarket than used oem for the $$$...
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post #16 of 33 (permalink) Old 07-27-2011, 07:22 AM Thread Starter
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Personally I can get just as good performance from a stock CDI that extra 1000 RPM isn't going to do anything your power curve starts to fall off way before redline anyway all you did was increase the red line, and as far as timing curve is concerned you can advance the cam or retard it and get the same effect. doing either of these is to be done with caution since these engine are an interfearance valve train. but this is all my opinion. If you want a cool aftermarket performance CDI by all means.

"MOOSE WAGON "
00 TRX400EX aka "MOOSE ROCKET"
91 TRX250X aka "MOOSE WAGON" RETIRED
96 Polaris 400L sport (Mrs. Moose Ride)
07 Suzuki LTZ250 (Sons)
96 Polaris 250 Trail Blazer (daughters)
06 TRX450ER aka === Under construction

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post #17 of 33 (permalink) Old 07-27-2011, 03:19 PM
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Quote:
Originally Posted by Reece616 View Post
definitely will do!
Ok, we are going to hold you to it!!


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post #18 of 33 (permalink) Old 07-28-2011, 12:52 AM
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well an aftermarket cdi does more than just raise the rev limit.. a good one will also smooth out all the peaks and valleys in the timing curve creating a smoother power flow balancing it all out, making for nice smooth power building up all the way to the new red line; so your power doesn't fall off short of redline.. this is where all your supporting mods come in such as intake and exhaust. think of it this way, your engine is nothing more than an air pump. the more air you can pump in the more air you need to pump out. hence if you increase the flow of air intake the need to add a higher flowing exhaust increases to pump out the larger volume of air. but now you cause a lean condition in the cylinder so you need to add more fuel to compensate and richen the mixture, this is where jetting comes in. this all causes a need to ignite the mixture at a different time depending upon where you are in the rpm range and how much throttle is aplied and how much load there is on the engine to produce an efficent spark to fire in the cylinder which causes more horsepower.. you see horsepower is a byproduct, a result, not the cause. and this is why an aftermarket cdi box is neccecary once you reach a certain point in your modifications which is also why you see stage 1,2,3 cdi boxes, each one is designed for different stages of modification... stage 1 for simple mods such as basic intake and exhaust, stage 2 for when you go beyond basic and add a cam and possibly a larger bore, and finally stage 3 for when you decide to get really wild and add some head work such as porting and polishing and maybe some bigger valves to flow way more air both in and out and a really agressive cam.

stage 1 would be for fun trail riding, stage 2 for agressive trail riding and some racing from time to time, and stage 3 for all out racing.

hope this sheds some light on things and helps to explain more, what a cdi box does and how to properly choose the one you should be getting for your needs, and why/when you SHOULD be getting one.


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post #19 of 33 (permalink) Old 07-28-2011, 06:45 AM Thread Starter
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I understand you're point , but from my experiences with aftermarket CDIs I haven't noticed a gain through them at all, and it's very possible it was due to them being a lesser expensive brand? I guess I'm more old school degreeing in cams, hotter coil packs ect, and displacement. lol if you have everything in balance and precise then that same power can be achieved. but we are not here to argue since most opinions that differ will lead to that. lol, I'd say if you want it buy it if not don't. lol

Thank you for the information none the less I'm never too old to learn...lol

"MOOSE WAGON "
00 TRX400EX aka "MOOSE ROCKET"
91 TRX250X aka "MOOSE WAGON" RETIRED
96 Polaris 400L sport (Mrs. Moose Ride)
07 Suzuki LTZ250 (Sons)
96 Polaris 250 Trail Blazer (daughters)
06 TRX450ER aka === Under construction

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post #20 of 33 (permalink) Old 07-28-2011, 04:37 PM
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no. you are right. you will not notice much of a gain at all just through the addition of a cdi box... rather a CDI box is more like the frosting for your cake.. bake your cake (do your mods) then add the frosting (CDI box) you will enjoy the cake more.. lol the cdi simply enhances the mods you have done. and is more for those who have no experience in degreeing cams and setting timing manually. but that is not to say that even someone who degrees their cam and manually adjusts their timing wouldnt see a bennifeit from adding a cdi box aswell.. but there isnt as much need for one for someone who does. and your other note on the aftermarket coil, that is not something I hear mention of verry often, but IS verry bennificial and should also be added at some point in the mod process. the combination of the 2 ( which is why you often see them sold together) is very much like adding an aftermarket (such as MSD6al or a JACOBS) ignition box and coil in race cars.. you may not really notice the difference in performance if you don't really know where to expect to see it.. a hotter coil and a multiple discharge ignition box will give the most noticeable gain and noticable performance increase under heavy load (lugging up a hill in a higher gear or towing) other than that you really wont notice much of a performance increase however you will notice better efficiency and smoother running and only if you are really in tune with your machine on a personal level. ( I can jump on my machine and tell if something is wrong just by how it sounds and feels).. with that said; just because you don't notice it don't mean its not doing its job.. some performance mods arent meant to neccesarily add horsepower but rather to enhance overall performance.

I am not here to step on feet or to start arguments. and you are right, if you want it add it if not don't. but when making the decision make it a fully informed decision and that goes for any mod you do to your equipment, don't just do it because this guy or that said it was good or bad or because your buddy is doing it or your mechanic said it was so. I am simply information sharing from my years of racing experience and research (cars, trucks, boats, bikes, quads, snowmobiles) they all use internal combustion engines and there is alot of information that crosses over through the platforms.

peace
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