Bajaj 12v conversion kit CDI unit

Hi everyone,

I have a bajaj electronic ignition kit installed on my Vespa GT 125. So far so good although I am a bit worried about the Bajaj CDI unit. I have read many posts in different forums, that the Bajaj CDI unit is not very good and sooner or later fails or dies.

I would like to know if there are any other CDI units, besides the Bajaj, that can be used with the Bajaj 12v conversion kit.

I would also appreciate any coments on the kit from those that have had installed for a while.

Thanks to everyone for any help or tips, or for just reading my post.


So I can use the Bajaj kit and use a different CDI unit? Is that what you mean? I ould like to use the kit but with a different CDI unit. 

Any suggestions will be greaty appreciated.



Short reply - If SIP doesn't carry them there's a 6$ CDI box that's black and sometimes purple. Solid plastic cover. The quality of the outside of the small box is sturdy and it's heavy.. looks a bit like a toy from a Happy Meal and probably not malossi superquality but it feels good compared to the other two CDI boxes I purchased trying to attain a complete kit from the "Convertion kit" i purchased from Canada but was shipped from India.

Haven't tried it but it is compatible with the Bajaj system that I have and is probably compatible with yours too.

I've seen the two matched together in charts and photos. 

I'm not even going to mention the name of the store/stores from where I picked up my kit but the CDI box purple and sometimes black box is 6$ and seems to be sort of a standard with Bajaj conversion kits.

It's small and you can pick it up on The airmail was cheap. Think it was 10$ total or something like that. It doesn't say Bajaj Calcutta. Been a while since I saw my collection of CDIs for my GL150. I think there was a japanese name on the back but i wouln't bet my life on it. I believe I ran the name on Google and got something that looked like a supplier with no interest in building a name. 

Just bought a new computer since my old frankenstein DIY Macbook left me cold, otherwise i would have a link with a photo. The box i'm refering to is about 3x3 and 4cm on the lengh. Connectors on the bottom of one short end.

Just a thing you might want to try if you feel your CDI is not working properbly and 10$ is a life saver if it would break down on you. Not sure of the width of the connectors but the are around 4mm each and I think there's a hole in them if you want to go cowboy and just run the cable through the hole so you can get home.


Three years ago I purchased a conversion kit for my GL150 from 1962.

I went electronic since I had the original ORIGINAL 1962 system with coils as older the some SIP members parents and an electronic kit was as much as buing all the super easy old school two coils, breakers and so on. It had the classic problem of not starting when moist and not starting after running long runs so it was easy to fix if your born 1980 and have did your homework on 70's Puch, Zündapps, MCBs and all the ones you could pick up for a song back in the early 90's..

Anyway story starts with a run down system. The spareparts to restore it and running original is about 180€. Buying an 12V electronic kit is around 210€. It was snowy winter in Sweden when I bought the beauty and I thought it would be fun to work on it.. I figured it was the same old school stuff I did when I was 12 (but with a vespa twist to it and even less precision than the 70's motorcycle frame bikes) before all the cpu controlled injectionsystems and reed valve stuff that came along for small engines just a couple of years ago. "-Piece of cake!"


No no no!! Nightmare! 

1. I bought a box from a dealer in Sweden was a bit reluctant since he'd bought it a year back for his own bike but hadn't had the time to install it. He had around four scooters. Turned out it was for a PX200. Same flywheel and statorplate but wrong cables and the wrong boxes. It took me a long time to draw that conclution since there's were basically no complete diagrams. I had two but none of them matched the parts. The dealer had bought it from Canada and he hadn't even opened the box. I should have sent it back but would have been expensive since he lived 800kilometers from me and he was a really nice old man who found lots of original details for the bike and sold me really cheap so I saw no sense in makeing it his problem

2. So I just checked out the canadian page where he'd bought it. 

They had the same kit and I found a diagram intended for it that was complete nonsence. 

This company restored vintage bikes made out exactly like the customer wanted it and sold it to people in Hollywood, Miami, New York and so on. I picked up a new wireing loom that turned out to be for a short frame, then i purchased a CDI box and some electronics from them and later a CDI box from Ebay i believe to match the diagram.. but the loom was wrong and they insisted it was the right one.. yeah right.. my bike is just 70cm to short from an accident that day at the Piaggio factory? 

3. I was born with a screwdriver and a love for electronics but i couldn't get it together. I had half a dozen friends who build motorcycles from scratch starting by welding the frame and then adding car engiens or what ever they find that is fun.. Madhouse engineers with degrees as well as greasemonkeys who use bubblegum if necessary, old guys as well as young guys.. They all had their share of headache. It's not a motorcycle, it's not a scienceproject with a formula to solve.. it's a vespa longframe with a big box of electronics, four wireing looms and three diagrams. One of the guys who's repaired a truck ignition in the middle the desert of Jordan with stuff he found and drove 1000km before it broke down.. He spent a whole afternoon doing his best and just went nuts and told me not to ever mention the bike again - ever. 

4. So I went fishing at the forums for somebody who had been through the same mess, uploaded photos of all the parts and the diagram. The guys at Modern vespa and other communitys had a big go at it and no one seemed to be able to solve it. 


So either buy a system from SIP if it's easy to hook up and guaranteed to work

- or walk pass a thing of true beauty and craftmanship, all original crome details, sissy bars and get a migrain everyday for four years. I moved the damn thing cause i don't want to see it and since i've spent 250€ and four hours running the wrong wireloom through the frame.. I don't want to spend another 200 and end up with twice the agony.. 

Admire those who get it to work. I had an idea of sending mine to Vietnam since they're used to repair anything with anything and get them running in millions and keep running for another 50 years just restoring the old engine parts.

I should have bought one from over there. Trouble is they're not into classics unless there's an american or european company envolved and then the price is twice as much.. or you get a pink one with strange flowers and a brand new breaklight from a motorcycle. 


A lot of the early 60's i've seen for sale over there have been restored to.. one guy had a microwave oven in the back of his. It was mounted with plastic padding and much love in covering the gaps.. but i don't want a Pre-Quadrophenia vespa with a 12V? microwave oven or a big bowlshaped thing in the back suitable for a large dog. 


Sorry guys but i'm in so much agony now that summer's here for the third time and it's still in pieces. If anyone has an idea please PM me or post here.. 

The 6$ CDI should work better than the bajaj since i've seen it on sooo many pages and.. i've been surfing for info on conversions since november 2005. 

hi ...

the bajaj infact is not the maximum

i resolved it in this way ....


I ve mounted the bajaj an removed the cdi box and the pickup and changed it with the piaggio parts



So I can use the Bajaj kit and use a different CDI unit? Is that what you mean? I would like to use the kit but with a different CDI unit. 

Which Piaggio parts can I use with these kit?

Any suggestions will be greaty appreciated.