Performance Modified New REED VALVE Engine; BT911 50x40 bore and stroke.

Grubee Inc


NEW BenTeng 50x40 BT911 ENGINE: 


Pizhou BenTeng BT911 80cc 50x40 piston port reed valve engine.  Sometimes referred to as the BT100-V2 by BikeBerry. 

Heads Up; This add is for the BT911 Engine only, Installation parts shown for illustration purpose are not included. 

This new 50x40 engine is nearly 80cc in displacement. 

California dealers use the coefficient of BS to wrongfully call a 79cc engine a 100cc engine.   

No BS in Oklahoma where 1 and 1 = 2, not 3.    Go figure 50x40 engine displacement calculation = 25mm Piston Radius squared x 3.14 Pi x 40 stroke = 78.5cc.  

Check out the pictures to see the diff between the new BT911 and the old BT100. Both are 50x40 bore and stroke. 

Gru-Bee will be selling DB Performance Modified BT911 engines only; However, they will come with a muffler pipe as the cylinder connection is quite different.

The BT911 shares the same muffler as on the BT100.   FYI:  No one has a plenum expansion chamber exhaust on the market at this time, but Wali Abdul Salaam says he is working on it.  TBD.  

We will not be selling installation Kits for this engine as there are too many individual variables available to justify it.   ie:  3 tank sizes, / 6 sprocket sizes, / 2 CDI ignition versions and too many different carburetors to list. 

BenTeng in Jiangsu Province of China has begin production status on this new BoBingBee Special 50x40 engine. 

 It has a clone Taiwan 911 cylinder that Don Butler does his famous port work on and adds in a third transfer port.   see pics.

#1.  Mr. Butler removes the standard SD ignition and installs the TZ HO CDI ignition.  FYI: The SD ignition only produces a 1/2" air gap spark and the TZ HO produces a whopping 3/4" spark.  That's a big plus point. 

#2.  Instead of the standard China doll carburetor Mr. Butler gives you an OKO 21 high performance carb and corresponding intake tube plate.  See Pic.   That's a big plus point. 

#3.  FYI:  The cylinder 4-hole head bolt pattern is not the same as found on the YuanDong LD100 or YD100 50x40 engines.    NEWS you can USE.

#4.  For better cooling the BT911 head fins are in line with the wind as opposed to being positioned incorrectly perpendicular to the wind as found on the old BT100.   That's a correction plus point. 

#5.  Therefore, the BT911 head should cool better.   However, it just a matter of time until someone makes a HO CNC 7cc head. That's a big plus point. 

#6.  6203 Crank bearings are bigger than the 6202-size found in other China Doll engines.   The piston Wrist pin is 12mm dia. with a 10-pin needle bearing. That's a big plus point. 

#7.  Butler does his famous balance job on the crank by adding in 6 more specially calculated size and depth holes to the 2 flywheels thus giving better balanced for vibration reduction.  That's a big plus point. 

#8.  Engine has (4) front and (2) back 8M mounting studs.    That's a big plus point. 

#9.  Don Butler BT911 engines come with the G2 Dio reed valve installed with an OKO 21 Carburetor.   That's a big plus point. 

#10.   Don Butler test runs each and every engine he builds. He Debugs so you don't have to. That's a big plus point. 

NOTE FYI:  A BT911 data sheet is attached in Jpeg picture format. 

Check this add to see any new information as we learn it.