Kymco 100cc swap

[JJJoseph]

I noticed recently in Taiwan the 2006-8 Kymco Sento 100, which is a regular 50cc Sento with a bigger crankshaft and cylinder in the 50cc frame.  The engine model# is SG20. Really nice, snappy small-frame scooter! Good for 65 mph.  It looks like about a 1 hour engine swap into a standard 50cc frame.  Does anyone know where to buy a complete engine here in America?  The regular Chinese qmb139 engine dealers (same as the Sento 50cc) don't offer the 100cc variant in the USA, and the NewSento 110cc is a different animal.

[245luigi]

Is it 2 or 4 stroke?

[JJJoseph]

It's an SG20, which appears to be a big bore model of the Kymco KG10 4-stroke which in turn is part of the QMB139 family of engines.

[ophelia]

I asked my colleague if it was possible to acquire a motor through official, legal channels for transplantation a month ago. He said no. The motor has not met EPA emissions testing. Private off-road use or not, he cannot bring it in.

I am curious if you could privately bring back a specimen...

[zombie]

Here is the COMPLETE deal right cheap. I have been running this kit in a 2006 QMB 139 for 2 years. No issues.

100cc Big Bore Performance Kit GY6 50cc 139QMB Chinese Scooter Parts 50mm Bore | eBay
http://www.ebay.com/itm/100cc-Big-Bore-Performance-Kit-GY6-50cc-139QMB-Chinese-Scooter-Parts-50mm-Bore-/161018154007?pt=Other_Vehicle_Parts&hash=item257d6e0c17&vxp=mtr

Actually One issue... The first cylinder head I got did have an intake valve leak. The seller replaced the head, and included a new gasket set.
If you really want 65MPH from it you also need a 24mm carb.

GY6 150cc Moped Scooter ATV Go Kart Carburetor Carb Sunl Roketa JCL Lance QMB139 | eBay
http://www.ebay.com/itm/GY6-150cc-Moped-Scooter-ATV-Go-Kart-Carburetor-Carb-SunL-Roketa-JCL-Lance-QMB139-/350996964210?pt=Motorcycles_Parts_Accessories&hash=item51b90ca372&vxp=mtr

And a free flow pipe

Scooter Performance Exhaust System Gold GY6 50cc QMB139 Chinese Scooter Parts | eBay
http://www.ebay.com/itm/Scooter-Performance-Exhaust-System-Gold-Gy6-50cc-QMB139-Chinese-Scooter-Parts-/161101259968?pt=Other_Vehicle_Parts&hash=item25826224c0&vxp=mtr

Or just get the whole kit for under 200.00USD. I ride EVERYDAY rain or shine, and tell you the truth... This is just about bullet proof. Drill two 1" holes in the air box lid, and you are good to go. Don't bother using the foam air filter w/ the kit unless you want to push home in the rain...

100cc Big Bore Kit Performance Power Pack Black Exhaust 139QMB Chinese Scooter | eBay
http://www.ebay.com/itm/100cc-Big-Bore-Kit-Performance-Power-Pack-Black-Exhaust-139QMB-Chinese-Scooter-/161052658160?pt=Other_Vehicle_Parts&hash=item257f7c89f0&vxp=mtr

[245luigi]

Will final drive gears be needed in that kit?

[zombie]

No. I never touched the gear box. The 139 QMB will cruise at 50MPH all day long, and top out around 60. I have an 8 mile (each way) commute on a section of 2 lane Hwy, everyday. People will sometimes pass me but not often.
I have bought ALOT of China crap but these kits, and Cheap ass engines are as good as anything else out there.

In two years I have replaced one crankshaft due to a wallowed out keyway on the taper end, two CDI's, one Carb, and that egg shaped block that sits under the intake manifold. Nakaru makes an aluminum replacement for that.
Still on the same kit I posted

[zombie]

Here's the bike...   Vruk!  Verucci/Ruckas hybred

[JJJoseph]

these kits, . . .  are as good as anything else out there.

The kits are OK (I have one in my Kymco 50cc) but I'd really like to get a complete 100cc unit from Kymco.  That way, the carb is done right, the gears are done right, the air filter is done right.  Everything is done right, and it shouldn't cost much more than the kit.

[zombie]

Price a kit, ... price an engine, and re-post your last post. We will wait.

[JJJoseph]

We will wait.

Is that for me? Wait for what?

[ophelia]

What zombie is saying is that we would be curious about the price difference and breakdown between your two options that you have suggested.

[zombie]

Zactlyee. You can kit a QMB for 1/2 the price of an SD engine. new.

I had to edit... You can buy two new QMB's for the price of the Kymco, and spend another 50 for the 100cc kit.

[JJJoseph]

You can buy two new QMB's for the price of the Kymco,

I might be misunderstanding you, but if you know the price of the Kymco 100cc, tell us.  How much is the Kymco 100cc (not a kitted 50cc)?  If you have the answer, tell us - don't make us beg for it :-) Also tell us where to buy it.

(By "100cc" I mean a Kymco 50mm bore x 50mm stroke, short case, with high-speed gear set, not a 50cc with a BBK.  The crankshaft alone could be $300)

[scootpower]

Would like to add my experience in building 139QMB engines over the last 12 years. The largest kit that will install and that is made is 85cc at 52mm. The 100cc kits that are sold all over the internet are simply not good and most are 70cc at 47mm. There is no such thing as 100cc for the 139QMB engines. I have seen many a so called 100cc kit that were install come to my shop for a new piston and the 47mm fit perfect. NCY is the only distributor that has 52mm kits that come with the correct head. Naraku makes one but the exhaust port is no larger than stock so performance is limited. The correct built CVT with a good kit from 70cc  -85cc that will be 47mm, 50mm or 52mm will last a long time. The correct CVT parts are a NOT worn out clutch and bell, proper torque spring for rider along with a variator that id not restricted which all stock ones are and you can see the restriction. The CDI in all 139QMB engines is limited to 7500RPM once again CDIs are not easy for Kymco which all are DC activated that I have come across. NCY does make the best AC pulse one for the 139. A performance exhaust is always needed to get the full performance out of the big bore kit.

Now in two stroke machines 52mm is 90cc or 107cc or 110cc. The scooters that have these stock are some Yamaha and others only in Asia. The way to measure CC's of your engine is TDC and then how much liquid is in the chamber. The Genuine Roughhouse uses s 52mm piston at 107cc

There are a few engines that are 85cc that can be bought in the states. Some of these are on ATVs from Kawasaki and others these are the 152QMB, in the model number for GY6 is the piston size hence 139, 152, 157 and so on. Have not seen a 90cc for some time the ones I have seen are in Linhai atv's for about 7 years now due to I sold plenty of them.

I am more than glad to help.