Honda Spree w/ Aero 125 CDI

[jerz40]

Hey everyone,
A couple months ago when I was browsing through the forum, I came across a topic where a guy had took a Aero 125 CDI box and plug it into the spree and when he did it gave it WAY more power. I just had to try this and when I did he was actually right! My stock 86 spree had a original top speed of 30mph, but when I plugged in the Aero 125 CDI I got a top speed of 35-36mph no problem!! Now, the problem is that when I do run the Aero CDI, the spree kinda stumbles at take off and acts a little funny and is a bit louder, but once you get going you FLY! What would be causing it to stumble at take off? Of course I know I'm running a different part and all, but what do I need to do to my spree to make it always run with the Aero CDI? Because I LOVE it that it has way more speed!
If anyones got a aero 125 CDI laying around, please try it and plug it in to your spree and see what I'm talking about! See if it stumbles at take off as well. One more thing, running an Aero 125 CDI won't do any damage to the lil spree, right? Any help would be appreciated! Thanks!

[Wheelman-111]

Greetings:

The main way an engine management computer can increase power is through timing advance. The spark timing on these things is controlled electronically, with the advance curve built in to the hardware. Earlier spark ignition can give more time (we are talking microseconds here...) for the fuel to burn more thoroughly because spark hits while the piston isn't finished coming up in the cylinder. That would account for a low-RPM stumble. But theoretically this early ignition results in more heat production and the resultant tendency of the mixture of gases to push down a little harder on the piston once it reaches the apex of its stroke and starts on its way down. There is possible harm if that heat isn't conducted away fast enough and combustion chamber temperatures exceed that of the melting point of aluminum. There's not much you can do if that's going to happen, and the catastrophe will occur suddenly and without warning.

[jerz40]

Greetings:

The main way an engine management computer can increase power is through timing advance. The spark timing on these things is controlled electronically, with the advance curve built in to the hardware. Earlier spark ignition can give more time (we are talking microseconds here...) for the fuel to burn more thoroughly because spark hits while the piston isn't finished coming up in the cylinder. That would account for a low-RPM stumble. But theoretically this early ignition results in more heat production and the resultant tendency of the mixture of gases to push down a little harder on the piston once it reaches the apex of its stroke and starts on its way down. There is possible harm if that heat isn't conducted away fast enough and combustion chamber temperatures exceed that of the melting point of aluminum. There's not much you can do if that's going to happen, and the catastrophe will occur suddenly and without warning.

Thank you for this info! What would you recommend I do if I decide to keep the Aero CDI in my spree? I like it that has more speed, but I don't like they way it stumbles and acts funny at low RPMs like you said. Do I need to change the Sprees Spark Plug Coil, to a Aero one from the same unit the CDI came from? There has to be something I can do to make this work. What about the Alternator behind the flywheel? Or the pick up coil? Hmmm

[MrJumps]

I think you have to move your timing, but that will retard spark and yet put you back where you where before. Running an advanced spark is dangerous from my understanding, yeah it may be faster but you may be throwing that bore away by running it with that cdi. Like 1man said its a ticking time bomb, if you really want to pick up power maybe the malossi cdi with adjustable rev limiter or stage 6 cdi, not the ebay s*** ones but a name brand one will probably have a better curve, you could try base gasket stacking or something like that. Im not really experienced with this but there is safer ways to gain that speed.

[Wheelman-111]

Greetijgs:

I recommend you restore the stock ECM and sell the hearty Spree power unit . Then post a Wanted ad for a variated engine to install in your Spree chassis. 40 or more MPH with much better pickup is assured.

[jerz40]

I think you have to move your timing, but that will retard spark and yet put you back where you where before. Running an advanced spark is dangerous from my understanding, yeah it may be faster but you may be throwing that bore away by running it with that cdi. Like 1man said its a ticking time bomb, if you really want to pick up power maybe the malossi cdi with adjustable rev limiter or stage 6 cdi, not the ebay s*** ones but a name brand one will probably have a better curve, you could try base gasket stacking or something like that. Im not really experienced with this but there is safer ways to gain that speed.

I haft to agree with you! Right now the Original Stock CDI is in the spree. And yeah, all those "Performance CDI's on eBay are s***! A couple of months ago I had one in my other spree, and one day I just couldn't figure out why it got all weird on me, then I decided to put the stock one back in and sure enough!

[jerz40]

Greetijgs:

I recommend you restore the stock ECM and sell the hearty Spree power unit . Then post a Wanted ad for a variated engine to install in your Spree chassis. 40 or more MPH with much better pickup is assured.

You are right! But my 1986 Spree is all ORIGINAL and looks still brand new so I want to leave it all that way, plus I love the stock look! But I was just looking for an easy way to give it a little more speed since my 86 special did 35mph STOCK! Kinda regretting selling my ol' Special...

[Wheelman-111]

Greetings:

All-stock is a worthwhile goal. I wonder how much performance would be gained by disassembly and a careful evaluation and massaging of the intake tract and transfer ports. Optimizing compression, squish and - If you really know what you're doing - the combustion chamber might bring more gains. There's always Taz's big-bore and taller (by 1 tooth) gears. None of this alters the stock appearance. That would leave the small airbox inlet size and an underachieving exhaust as the limiting factors.

[patthesoundguy]

Those fleabay so called racing cdi boxes really suck sometimes, I think it's because they are meant for 4 strokes not 2 stokes. Bought one a while back for the heck of it. Sucked monkey rear ends on my dio. But I used it on the Honda clone on my landlords kids dune buggy and it worked so well to replace the stock cdi that died it was crazy. The bottom end was perfect and the whole torque curve was amazing.

[jerz40]

Greetings:

All-stock is a worthwhile goal. I wonder how much performance would be gained by disassembly and a careful evaluation and massaging of the intake tract and transfer ports. Optimizing compression, squish and - If you really know what you're doing - the combustion chamber might bring more gains. There's always Taz's big-bore and taller (by 1 tooth) gears. None of this alters the stock appearance. That would leave the small airbox inlet size and an underachieving exhaust as the limiting factors.

Yes I actually purchased a Big Bore Kit before and man do those kits give the spree some major guts! The floorboard vibrated my feet! Unfortunately I could never figure out why the spree would have such a hard time restarting and ended up selling it a while back....

[jerz40]

Those fleabay so called racing cdi boxes really suck sometimes, I think it's because they are meant for 4 strokes not 2 stokes. Bought one a while back for the heck of it. Sucked monkey rear ends on my dio. But I used it on the Honda clone on my landlords kids dune buggy and it worked so well to replace the stock cdi that died it was crazy. The bottom end was perfect and the whole torque curve was amazing.

Yea they do! But I'm happy you made one work on a machine! If only I could get one to work on spree....

[MrJumps]

The stage 6 one has a remapped curve meant for the honda line 2 strokes.

[jerz40]

The stage 6 one has a remapped curve meant for the honda line 2 strokes.

Where do I find this part at? Thanks!

[MrJumps]

http://www.scooterswapshop.com/collecti ... stage6-cdi

Found one of ebay a while back for 10 bucks cheaper but shipping so idk, he also has the malossi ones too, whitch i cant out source either. Also try treatland for spree parts too, sometimes they have the mlm sidebleed pipe and a cdi or too, your looking for an 5 pin advanced cdi.

[Wheelman-111]

Greetings:

You may be seeking this.