hey oregon patrol, where can i find the big gun cdi, how much does it add on top speed? also i heard when u get a rev box u have to get lighter valves and stiffer springs, will i have to worry about blowing or messing up my engine?

 

The Vortex for the EX should be out in a few months - I like the idea of choosing curves without switching the CDI.

 

hey oregon patrol, where can i find the big gun cdi, how much does it add on top speed? also i heard when u get a rev box u have to get lighter valves and stiffer springs, will i have to worry about blowing or messing up my engine?

 

You can get the Big Gun CDI from most dealers, including Big Gun directly. Top speed wont increase that much, but you'll get there faster. No, you dont have to get any other components for the Big Gun rev box, but it does increase your stock rev limit by 1,750 RPM. If you rev that high alot, its probably a good idea to consider stiffer valve springs. The White Bros CDI is basically unlimited - that will cause some concern with valves floating.

 

W/ out getting in to the engine the cdi and rev boxes dont seem to make sense. If your engine is stock inturnaly then why would you need to change the cdi? The stock cdi is programed for the prameters of a stock engine. With a filter and a pipe you are moving more air then get an aftermarket or xr cam so the valves open longer. Your hp peak is ushally higher then comes the cdi & rev box. I dont mean to bash anyone but I have already done this process and know how the bike reacts to each mod.

 

Oh and speed deemand13... the cdi dosent change the top speed though it does change to time at which it takes You to get to the top speed. The rev box will change the top speed more rpms higher top speed. How much? well like many products out there some but not alot.

 

Quite simply the power curve is pushed up to the higher RPM range giving more power there. The stock curves are more flat. What we are talking about here is ignition timing. You can make ignition timing changes and keep everything else the same and you will notice a difference. There are plenty of them out there, I suggest, if you have the opportunity, to borrow a CDI from someone and try it. The CDI on the 400EX is easily swaped out in about 30 seconds.

The Stock CDI is not for race conditions, but more linear or even power accross the RPM range. Its a general purpose CDI for everyone, but everyone does not use it the same. When you race, you want power on top of the RPM range. The stock CDI does not do this.

 

Yes you can gain some but with out a cam you can only tune so much.+ to get to higher rpms the rev box is needed first... but I guess some of them have one built in. Add a big bore kit higher comp. and a cam whew you will notice a huge gain. All that is not much more than one of the nice programable cdi's.

 

I have the Vortex - multi-curve CDI for my DS and have lots of experience with these. You will notice a huge improvement, no matter what mods you have, with any EX aftermarket CDI. The multi-curve CDIs are pretty much the same top end curves as the single curve CDI's. I dont think you'll find much difference in the top performance curve on a programmable CDI when compared to an aftermarket single curve CDI. Ive run them all. The multi-curve CDI's simply have more to choose from at your finger tips. I do not recommend re-programming the EPROM chip in these CDIs. The DS guys have gone through several problems in the past resulting in engine damage. My feeling is that these companies that produce the pre-programed multi-curve CDI's have thier butt on the line and if there is a failure in timing, they will back them up - the R&D for the pre-programmed curves is huge. The guys that have EPROM burners better have a lot of ignition timing experience, and a dyno to program them correctly.

mxer250 - Its not a situation where a person has to choose a piston or the CDI - if you get both, your gain will increase by the use of both.

 

Im sure they are great systems but still I dont think that your can gain that much. Plus lets say you want more then your going to have to do the engine stuff anyway but bthen you will have to try to tune the engine while trying to change the cdi curves for the engine mods. Do the engine mods or some then do the cdi. I dont have an aftermarket cdi but a whole lot of engine mods i ran even with a yfz all day long. tell me that you could do that with just a cdi and a ppe and filter.