whats needed to derestrict like 50cc 4t

[LoveMyKymco]

That cdi style is the 139qmb style for any chinese scooter.

[JJJoseph]

That cdi style is the 139qmb style for any chinese scooter.

LoveMyKymco, why don't you try being helpful instead of trying so desperately to show that you you're smarter than anyone else? Kymco CDIs and standard 139qmb CDIs look alike, but some are AC, some are DC. That is, they're different electronically even though they look similar.  A Kymco CDI requires a Kymco stator, and won't run with a 139qmb stator.

[LoveMyKymco]

The kymco cdi is DC. Its not that hard to find one.

[JJJoseph]

The kymco cdi is DC. Its not that hard to find one.

LoveMyKymco, nobody said the Kymco CDI was hard to find.  I uploaded a photo to show that it's similar to a standard Chinese qmb139 CDI, but they're not interchangeable even though they fit.  Nothing was said about them being hard to find.  The OP was asking about derestricting his 4T.  If you can't be helpful, resist the temptation to barge in with unrelated comments.  How are you enjoying the dialog? Do you still enjoy telling others that you know more than they do?  I'm so pleased that I'm able to help you enhance your self-image.

[LoveMyKymco]

Yup, you got me buddy. Sure did. Wooheee

[johnson]

Yes, and this stimulating and almost helpful conversation is why there are so few people active on this forum.

[Monty33]

So, aside from the amusing banter going on within this string....did we ever get a good answer?
My wife has a 2009 Sento 50cc and it only goes about 28mph.  I've got to do something to get just a few more mph out of it.
What's the best (most simple) way to do that?  I can replace a CDI if that'll work.  But, more complicated things like upjetting are out of my technical league.

Any realistic help would be appreciated.

[Monty33]

So, I called Kymco USA today to ask them what the best way to derestrict a Sento 50 was (or some way to just get a few more mph out of one).  Their technical department told me that, for liability reasons, they could not tell me directly but that I should check out this forum (although it is not sanctioned by Kymco).
They also said that my dealer could call them to find out the best way to derestrict the Sento.  They just won't tell a consumer directly.

So posters....what is the best way?

[BettinANDlosing]

They have a Like 50 4t out of the states? Weird. And most of the 4t Kymcos DO have the restricted BOSS in the variator.

[JJJoseph]

They have a Like 50 4t out of the states? Weird. And most of the 4t Kymcos DO have the restricted BOSS in the variator.

The Sento 50 & Like 50 are delivered with the restricted boss from the factory, but the dealer removes it and replaces it with an unrestricted boss, upping top speed from 25mph to 29mph.  From this point, your options are (1) unrestricted CDI as described above (2) remove collet in air intake (3) one size larger main jet (4) max tire pressure.  Your top speed should now be about 32mph with a light tailwind. Next comes Big Bore kit, gears, exhaust, to get you to 45mph.  Kymco won't help you with any of this, you have to go to the black market (which is usually very helpful). For instance, Scrappy Dog Scooters.