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General => Technical | How To => Topic started by: drewbo on November 27, 2013, 01:35:00 AM

Title: whats needed to derestrict like 50cc 4t
Post by: drewbo on November 27, 2013, 01:35:00 AM
Hi guys, hows it going i'm new to the forum.

Bought a Kymco like 50cc 4t out here in Australia a few months back and its running well.

Looking to derestrict it and there is a few differing opinions online. Just wondering if anyone has done it on this 4t model and if so what do i need.

Thanks in advance

Drew
Title: Re: whats needed to derestrict like 50cc 4t
Post by: 245luigi on November 27, 2013, 02:08:18 AM
What speed are you hitting??
Title: Re: whats needed to derestrict like 50cc 4t
Post by: drewbo on November 28, 2013, 01:29:20 AM
Just hitting 50kmph, if its a big hill im hitting 55.  ;D

Could just do with an extra bit of zip to stop the traffic tailing up behind me.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on December 02, 2013, 04:30:51 AM
Looking to derestrict it and there is a few differing opinions online. Just wondering if anyone has done it on this 4t model and if so what do i need.

The stock Kymco Sento 50cc CDI restricts max rpm, but can't be swapped with an unrestricted Chinese CDI like most other 50c scooters.  I found an unrestricted CDI for Kymco Sento 50cc at Scooter Assassins.  It adds about 8kph, so it's useful, but it's a bit expensive.  Not sure if this will work with the Kymco Like, but they'll answer your questions.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: 245luigi on December 02, 2013, 05:54:11 PM
The 2 stroke has a derestricted CDI stock. Try emailing kymco and inquire as to if there is a rpm restrictor on the 4t.

Open the CVT and see if there is a washer on the variator slide. Thats where the restriction is on the 2t.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on December 03, 2013, 10:23:10 PM
The 2 stroke has a derestricted CDI stock. Try emailing kymco and inquire as to if there is a rpm restrictor on the 4t.

Open the CVT and see if there is a washer on the variator slide. Thats where the restriction is on the 2t.

He's got a 4T not a 2T.  The 4T is severely restricted and it doesn't use a "washer" in the variator, it uses a restricted bushing that is usually replaced by the dealer with an unrestricted bushing at delivery time in unrestricted regions.  In addition, the 4T has a restricted CDI which I described above.  It's not helpful to be guessing at answers if you don't really know.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: drewbo on December 04, 2013, 12:19:28 AM
Thanks for the input guys, i'll ping Kymco an email and see what they say!
Title: Re: whats needed to derestrict like 50cc 4t
Post by: drewbo on December 05, 2013, 12:37:07 AM
Got a reply back from a company called monster scooter parts-

Hello,

Thank you for contacting Monster Scooter Parts.

We have not been able to verify if this part is compatiable with your scooter.  This is a part for a 50CC Kymco scooter though. 

If you have any questions or if you need further assistance please let me know.

Thank you,

Michelle R.
Monster Scooter Parts
800-798-0325 ext. 118
www.monsterscooterparts.com (http://www.monsterscooterparts.com)



Still no further forward.

Title: Re: whats needed to derestrict like 50cc 4t
Post by: drewbo on December 05, 2013, 12:40:29 AM
JJJoseph what year is your scooter? If they are similar i would imagine the CDI's would be the same?? Mines is 2012.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on December 13, 2013, 12:04:46 AM
My Kymco is a 2009 (qmb139 engine with carburetor).  If yours is fuel injected, it's different; carbureted is the same. 

I said above that I got my unrestricted CDI from Scooter Assassins, not Monster Scooter.  The one from Monster is different so I can't confirm that it works.  I'm not saying it doesn't work, only that I don't know.

The CDI I bought from Scooter Assassins is confirmed for a Kymco 4T, and it works.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: Glennza on December 18, 2013, 04:29:25 AM
Might want to check and see if there is a collet inserted into the airbox intake too. If so, take it out!
My Like 50 4T had it.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: drewbo on December 20, 2013, 07:05:58 AM
Glennza what exactly did you do then to get in derestricted?

Same as what the guys have said plus take the collet out?
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on January 08, 2014, 05:25:25 AM
take the collet out?

When you take it out, it will run lean and stumble on acceleration.  You'll then need to up-jet one or two sizes.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: LoveMyKymco on January 08, 2014, 03:45:19 PM
If you have the 2 plug style cdi there are many options, if you have the single plug style you are limited. Most sentos use the single style and Naraku and a few better higher end companies make cdis for them but you will have to find them on webike.com.
Naraku is junk electronics parts so I wouldnt even waste my time with them. Pure junk. I would never put anything Naraku on my bike especially electronics. Its like putting an autozone alternator on a Benz, or any other car for that matter.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on January 11, 2014, 06:07:58 AM
If you have the 2 plug style cdi there are many options

Here are some CDIs that work on a 2008-2009 Kymco 50cc 4-stroke:
Title: Re: whats needed to derestrict like 50cc 4t
Post by: LoveMyKymco on January 11, 2014, 03:57:18 PM
That cdi style is the 139qmb style for any chinese scooter.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on January 16, 2014, 07:41:21 AM
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.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: LoveMyKymco on January 16, 2014, 03:39:57 PM
The kymco cdi is DC. Its not that hard to find one.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on January 27, 2014, 04:18:49 AM
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.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: LoveMyKymco on January 30, 2014, 06:59:19 PM
Yup, you got me buddy. Sure did. Wooheee :-*
Title: Re: whats needed to derestrict like 50cc 4t
Post by: johnson on February 06, 2014, 02:29:45 PM
Yes, and this stimulating and almost helpful conversation is why there are so few people active on this forum.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: Monty33 on June 02, 2014, 06:43:23 PM
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.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: Monty33 on June 03, 2014, 08:25:54 PM
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?
Title: Re: whats needed to derestrict like 50cc 4t
Post by: BettinANDlosing on June 03, 2014, 08:32:44 PM
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.
Title: Re: whats needed to derestrict like 50cc 4t
Post by: JJJoseph on June 03, 2014, 11:09:19 PM
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.