I am getting a lot of people asking me, if their scooter has a restricted CDI, how to check if it is restricted and how to derestrict it. First of, I want to explain why CDI’s are restricted in the first place.
Why are some scooters having a restricted CDI?
To get one thing straight: Only 50cc scooters have a restricted CDI. I have never heard of a bigger engine model with a restricted CDI which is being shipped like that (if you know please leave a comment). Tho, keep in mind that there might be an additional third party restriction installed to allow for riding your scooter model with a certain license.
With this out of the way, let’s talk about the restricted CDI’s found in some 50cc scooters. The obvious reason for a restricted CDI is to ensure that they don’t go faster than the legal speed limit. You have probably read my article on derestricting your scooter and you might ask why some do a CDI restriction and some do another one. Whilst in my early years of scooter tuning all restrictions were mechanical, the restricted CDI only became popular in the last ten years or so. I was doing a bit of research and believe Japans government enforced the use of restricted CDI’s at some point. Why I can’t tell you exactly what happened, this explanation makes sense since Italian made scooters still don’t ship with restricted CDI’s up to today, even tho they share the same (Yamaha)Minarelli engine. This leads us to the next question
Which scooters have a restricted CDI?
Whilst this list is probably not 100% accurate it should point you in the right direction:
- Newer (after 2005) model Japanese 50cc scooters
- This includes Yamaha and Honda models (both 2-st and 4-st), especially those for the Japanese market. For example the popular Yamaha Aerox is built for the European market and still ships with an unrestricted CDI (please comment if you know more)
- Honda Ruckus/Zoomer appear to be CDI restricted. Tho, since performance of the stock 4-st Honda GET engine is very limited some people state different results. Don’t expect too much from installing an unrestricted CDI.
- Chinese 50cc scooters
- Pretty much all of the Chinese 50cc scooters have a restricted CDI installed. I can’t tell for sure why, but I believe the Chinese government might have enforced a similar rule, or the Chinese manufacturers just wanted to ensure that their models can be sold to the Japanese market without modifications.
- Piaggio 50cc injection models
- Whilst this is not necessarily a CDI restriction, the injection models by Piaggio have some sort of injection restriction in place that acts in a similar way as the CDI restriction. Apparently these can be unrestricted via a software update. Get in touch with your dealer about that.
How to check if your scooter has a restricted CDI?
If you believe your scooter is CDI restricted there are some easy tests:
- Right downhill. If your scooter is not going faster (or stops revving higher at some point) when going downhill compared to going straight, then you can be certain your scooter has a CDI restriction in place.
- Another way to check needs an RPM meter. Place your scooter on the main stand and make sure it’s secure. Ideally have someone to help you holding it in place. Rev the engine up slowly and check if at some point the engine stops revving for no reason. This is probably somewhere around 7-800rpm. If it revs higher than 8000rpm you’re don’t have a restricted CDI in place.
- Install a 70cc cylinder kit. If you scooter still doesn’t go faster than stock, the CDI is restricted :)
How to derestrict your CDI?
Whilst most of you are probably hoping that the CDI can simply be derestricted MacGyver style by cutting a wire, I have to disappoint. Whilst it is apparently possible to derestrict a CDI for some models (old Piaggio Purejet), most models require you to purchase a derestricted CDI. Companies like Malossi offer derestricted CDI’s at high prices, but if you don’t care about marketing and high-end tuning you are good to go with the cheaper models. I have now put together a full derestriction kit for the most popular scooters out there. You can find it in our new shop. We are shipping worldwide!
Check out the New TuningMatters.com 50cc Scooter Derestriction Kit!
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You have anything to say? Feel free to comment on this article, or post to the forum if you have any questions!