CDI box install and test (I expect to break 100mph)

what surprises me the most about this mod is that its been this long coming to light. i wish there was vid of it.

[TeamCheap]

Well I would say it is much easier to slap in a CDI than to try and mechanically adjust the timing which is really limited in what that can do.

I'm going to need some heavier clutch springs since I am on the heavy side and I really do work the clutch hard at times.

I think the worst thing I do is hold it full throttle (I dont back off) and just quickly shift so yeah the rpms go up fast so I have to be quick but it is hard on it but fun.
Not 1st to 2nd but 2-3-4-5 and I dont do it all the time just once in a while.

[CRidin]

So Do I go get it tomorrow or not. Dang the suspense is killing me!

[ambassador]

Zap, i couldn't agree more, Porterz had some good info too bad he wanted to fight everyone but if it weren't for his post I never would have tried a new CDI as I've never seen anyone try it before...
TC, I used to rip through the gears on my XR and never really thought twice about it but now that I'm older and broker I try to be nice to my GY, not sure my economic stimulus check will cover the DRZ that I want(not even close)..
AZ, By all means this is not the end all mod, the best mods I've done so far are the 42t rear sprocket and ditching the airbox, that took me to 70mph alone.. I plan on replacing the exhaust then rejetting (was trying to re-jet with drilled stock exhaust but why bother)..
I think after awhile the CDI and taller gearing are going to eat up my clutch, gonna have to add that to my list, new plates and stiffer springs, the GY's need stiffer springs from the get go IMO...

I thought about putting the 38t back on and wrapping myself in bubble wrap this weekend for a test ride but I don't think the clutch will be up to it so I think I'll just leave well enough alone...

[Kawazacky]

I say we let Porterz back on, and appoint him his own special moderator to keep him in line.

If he figures some stuff out, cool. If he blows his bike up, well, we can all learn from his mistakes. :twisted:

[CRidin]

Oh I bet back from death can relay messages for him. But on topic, do the guys that have it like it? And a question. these trannys are gear to gear with the crank in a round about way.Right? Ok how is this box changing your speed at any given rpm? Its all still moving together. Or am I misunderstanding the claims here.

[IronFist]

:mrgreen:
Actually I am intrested if/how it works too, not that I follow things too closely. Just from a scientific/mechanic point of view, shouldn't it open up the power to the whole upper end of the throttle in all the gears? Shouldn't you get a boost for dirt too in the lower gears? Unless I'm wrong about how it works? It's a more agressive sweep of acceleration, isn't it?

[TeamCheap]

Ok just my thoughts on it but the CDI box can only do so much.

It can not do much more than increase throttle response and open up the rev limit that is found in stock CDI boxes.

If it changes the ignition curve a bit and advances the timing then it could help wake up the motor which will give you a little more useable power that you could then regear the bike to use a bit better.

but no way are you going to go 80mph at a lower rpm than before the box its the fact that removing the rev limit could allow you to hit 80mph but the closer to redline the closer to POP.

The CDI box itself changes nothing mechanical on the engine it just adjusts the timing.

If the engine is turning 7000rpm's and it goes 65 then with the CDI box and the engine turning 7000rpm's your still going to go 65.

The benefits come in the advanced timing and the removal of the rev limit and to take full advantage you would have to regear for example rear 46T to a 40-42T and the CDI could with its increase in performance allow you to pull the gear ratio better than the stock CDI would..

[Back_From_Death]

Team Cheap -

With all due respect I read your response and realized that you seemed misinformed on how the "Magic Box" as Porterz founded the term and mod works.

With the box people are easily hitting mid 80 mph range with the proper basic supporting mods and tune. It does add ALOT of power with the proper setup and tunning. I can see you did not get as much of a benefit as others on here did. Everyone has different mods with different tunning so that is normal. You said it is very cold where you are, perhaps you need more fuel. The box does not add top speed just by raising the redline. It raises the top speed by adding a huge power increase primarily in the high rpm range. What I am trying to say is that the bike can do 80+ with stock GY-5 gearing without hitting the normal rev limiter or even coming close. With the normal rev limiter I could rev over 10,500. At 85 the RPM's are around 8 ish, no where near the stock limiter therefore your theory on how it adds top speed is incorrect. It does not add top speed by going over the redline and winding out the motor. It adds top speed by adding high end power. It also adds a good deal of low and mid power. It does all this by increasing the timing as the rpms go up, something the stock CDI does not do. When you get around 6 ,500 the timming is then optimal for the engine resulting in a huge boost and thats why you are able to pull thru mid 80 mph speeds.

If you did not get a huge gain perhaps either you don't have the correct set of supporting mods OR the tunning is off. Hope this helps

I would also like to add your correct about the rpm's being the same regardless of CDI's. That should be obvious to anyone mechanically inclined, I am not sure where you saw that somone thought the box changed the rpm when in a certian gear and a set speed.

[ob1]

lol

[ob1]

Ok, now, here is the shiznit..

The ultimate rev limiter is valve spring float, ie rpm beyond the ability of the valve springs to close the valves properly.

Since the motor is a rather simple mechanical device, and a CDI cannot change transmission of final drive gear ratios, a CDI can only get you to that maximum rp.m before valve float in a faster time.

Any additional rpm gained by the lack of a CDI rev limiter ENDS at valve float.

Those additional rpm do in fact equate to MPH.

The question is, do chinabikes have a rev limiter in the stock CDI? I know what a motor sounds like when it hits a rev limiter. I say they dont. Neither do the mainline brands for any of the small displacement bikes. Do you really think they leave 20% of the potential power untouched? Have you ever actually heard a bike hit the rev limiter?

The gains by using an aftermarket CDI are clear to me, as far as I know I am the FIRST one here to run one. I use the same one on my Lifan 200 that I use on my heavily modded XR100, and use the extra power by CHANGING THE FINAL DRIVE RATIOS to the achieve the maximum top end.

My 100, carrying 250+lbs, will beat a stocker carrying 70 lbs, every pass.

The aftermarket CDI is a good mod, but let's get serious, please. There are simple limits to the performance of any motor.

I shall test this alleged magic box and report my findings. Trust that only I can provide 100% authorized Zapkin product evaluations!

[Back_From_Death]

Originally Posted by ambassador

Hit 85 today in 5th at 8000rpm confirmed by GPS, bike does not feel comfortable at that speed though, probably because they were never mean't to go that fast...

[quote="ambassador"]Zap, i couldn't agree more, Porterz had some good info too bad he wanted to fight everyone but if it weren't for his post I never would have tried a new CDI as I've never seen anyone try it before...
quote]

Originally Posted by knothead

BTW... looks like Porterz might not have been stretching the truth when he said 90mph. Didn't he have gearing just a bit taller than a stock GY-5?

Originally Posted by Kawazacky

I say we let Porterz back on, and appoint him his own special moderator to keep him in line.

If he figures some stuff out, cool. If he blows his bike up, well, we can all learn from his mistakes. :twisted:

No worries... Porterz is alive and well.. In fact I am very close to him. In his free time he still continues to think of cool new mods and from what I hear he actually just finished a couple more new exciting firsts. :o I will be able to share them with you soon. He is also working on getting a helmet cam to record his 90 mph run while also making a neat offroading video showing how he puts his custom GY thru the paces in the ruff stuff. He also wanted me to thank his supporters for sticking in there and believing in him no matter what style welds he uses or what topic he decides to put his 2 cents in. He is pleased with continuing to get the word out on the magic box for more people to enjoy even though there are still many disbelievers and some that even think it does nothing at all :roll:

I will try and get some info up on his brand new mods within the next couple days. You won't want to miss it :wink:

[montanaoffroader]

Another consideration is the quality of the internal components in the stock CDI. If you don't have a clean, consistent signal to the coil, you aren't going to get all the power your engine is capable of producing.

IIRC, the early GM HEI units suffered from this very problem, particularly at higher rpm's. Installing better quality aftermarket ignition modules (same function as CDI) and ignition coils picked up a fair amount power in the higher rpm ranges, and allowed the engine to take full advantage of other mods (intake, carb, exhaust, etc.).

I'd bet that if you put an O-scope on both units you will find that the aftermarket CDI has a cleaner signal, esp. at higher rpm's....

Just my .02

[Back_From_Death]

Originally Posted by ob1

The question is, do chinabikes have a rev limiter in the stock CDI? I know what a motor sounds like when it hits a rev limiter. I say they dont. Neither do the mainline brands for any of the small displacement bikes. Do you really think they leave 20% of the potential power untouched? Have you ever actually heard a bike hit the rev limiter?

The gains by using an aftermarket CDI are clear to me, as far as I know I am the FIRST one here to run one.

Let me first off say that yes they do have a limiter, at least my GY does. And YES other dirt bikes have rev limiters and YES I have herd plenty of dirtbikes hit them both big and small bore. Maybe you should look up CDI boxes for different bikes on the market. You will see that most good aftermarket boxes will increase the limiter or in some cases eliminate it all together. If you did your HW on CDI's you would have seen in the ad for the AMR that the honda box will raise the limiter from 50cc bikes to the 400cc. The stock on most honda's is around 10K ish regardless of motor size. The box raises it to around 11ish. As far as being the first to put a box on that may be but Porterz was the first to put on the AMR Stage 3 box and that is suppose to add the most power. NOT ALL BOXES ARE THE SAME. In fact they are not even all similar. The basic boxes with advance the timming only untill 4 grand. The AMR will advance it all the way till redline. I actually have the data to compare and so far based on the data the AMR is the best one on the market hands down. It is so good in fact that unfortunately they will soon be raising their prices from about $60 to $100 as more people are beginning to want them and realize the superiority over other units. Id say even at $100 bolting on that kind of power is still incredible. I use it, in fact it is the best bang for the ease of install/buck mod I have seen yet and I am planning on buying their high output coil to compliment the system.