mopeds


Derbi CDI installation step-by-step
June 11, 2009, 3:58 am
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So derbi owners have pretty much always only had one ignition choice: stock (points or for some the electronic ignition found on the ds50). Now I’m going to show how the CDI treats sells can be adapted to fit your derbi. This is going to be for piston port bikes, but the same procedure will work for pyramid reeds, and should work for flat reed as well, just ignore the coil flip.

Buy CDI here

Ok, so you got your CDI which has a new stator, flywheel, cdi box/coil and maybe a regulator. This was on my race bike, so I pulled the lighting coil just to clean up the wiring a tad. Your going to need a dremmel or files to slightly modify the stator, a m4 tap and appropriate sized drill bit, and maybe some lock-tight.

The first obvious complication is mounting the stator in place of the old one. You’ll notice the diameter is a tad smaller, and you want it centered as well as possible for the best pickup to be sent to the box. So you are going to have to slightly enlarge the center hole (towards the lighting coil). Next you need to enlarge one of the screw holes so you can use two screws to hold the stator to your cases. I ended up using 2 screws, one just to the right side of the main ignition coil, and the one right above the lighting coil (see photo). The one above the lighting coil needs to be enlarged about 5mm to the left. You may need to pull the lighting coil off to mount the stator to your cases, but you can just re-install it once mounted.

Basically the lower screw is tightened and the plate shifted as far counterclockwise as you can get, so just enlarge the hole above the lighting coil so you can rotate the stator to that position and screw in the bolt. This position (with the pickup relocated) got me right at 1.8 mm btdc)

So now the stator is lined up, but the case is getting in the way of you wires out of the stator. You need to dremmel open the little supports for the crank bearings/seals (see photo). I believe you will only need to open up 2, the one just above the lower screw hole, and the one to the left of it.

With those done, the stator will just bolt on with the cables out of the way. You will still need to relocate the pickup (tap and locktight) and possible flip your ignition coil. I am running a za50 cdi box (counterclockwise spin), and had to flip my coil (note the position of the blue wire from the coil to see which direction). If you have an e50 box, I don’t think you will need to flip it, but always check with a timing light to make sure it sparks through the range.

So thats it, just a little modifications and this wonderful and cheap cdi works, and quite well at that. It really brought my bike to life, and is a nice departure from points. Now your only issue is figuring out where to mount the cdi box and coil. Also note, on one of our 5 piston port derbis, the cases were super weird with extra large supports for the crank bearings, thus not allowing the flywheel to fit inside. You could likely dremmel everything out, but I’d be careful.

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cuperteens race-prep

so while all the other teams seem to be doing all this crazy stuff, we’ve been keeping it pretty low key. I’m just going to accept derbi how it is. I know I could get a lot more out of it with a little porting, but I want to make sure it survives the weekend before I tear into it further. I also would like to mod the clutch more, but can’t afford another broken shoe, so that will also wait. The cdi and zen pipe paired with the disks already make it a fair amount faster than its last appearance in may (in which it earned the 3rd fastest lap time), so maybe it will be alright.

MagnumX is also going to be coming along and has received its own upgrades. 64cc of piston port magic make for some amazing torque. The pipe we made totally limits its top end, but its loud, and pulls pretty well throughout. I’ll probably ride it in at least one practice just for fun.

My brother is upgrading his tomos as I type, polini, 4 petal, etc. Again, won’t be the fastest bike, but it should rip pretty hard.

Justin (blasto) is riding the polini maxi which has a polini kit on it. I think its slow, and his pipe is going to scrape, but it has some amazing throttle response. Tom (broke dan’s arms) I think is just going to be riding speed racer again, but this time better tuned and a tad faster. He has some other builds in the works, but he’s all hush hush and I don’t know whats happening with them. Matt should just be riding his garelli/derbi monster. HPI, zen pipe, 75cc metrakit and a lomat 4 petal with a 24 mikuni makes a super blaster. My bike has more low end, but his mid-range/top end is insane. True blaster steez. No kinked fuel lines this time.

So thats it, no super hobbit/derbi/puch builds or whatever, although I kinda wish we were. I think Tommy and Jimmy should be ripping, but i know choke is working on some stuff too, so we’ll see. Everyone is upgrading and adapting very quickly. I do have leathers and plan to race as long as I’m healthy. I couldn’t walk yesterday, but spent most the day wrenching today, so I should be fine by friday. Either way, I’m super excited for the weekend. A long lost cuperteen returns!