ESP High Torque Championship Ported Zenoah 4-Bolt 36mm 29cc Top End Kit

THEY'RE HERE! The new Zen G290, 36mm bore 4-bolt cylinders are the most reliable 36mm bore that we can now use, and ESP was eager to add their Championship winning porting and head work. These kits are the newest and most powerful of the ESP Porting, the "New Generation High Torque" Kits. 
 
“We (the hobby industry) asked Husky/Zen for a 36mm top end, they saw the need and came through, but they surprised us by making them 4-bolts. Now we can work on making even more power, without the worry of breaking a cylinder off or the possibility of a premature plating failure (so you know your money won‘t just--flake away). I think you can expect a lot of fast engines being made from this top end” (Doug @ ESP)
 
The 4-bolt cylinders (G270/G290) right now have enough squish clearance to install a 1mm stroke crank with no head nods or cylinder gasket stacking (use the stock gasket), but that can change in the future, because the 2-bolt Zen G260 used to be the same way (now have tighter squish stock).
 

Here is the crank configuration ESP recommends with their ported and head modified 4-bolt head kits.
 
G270/G290-- No head mods (ESP ported, but squish band and combustion chamber left stock). Use either stock stroke crank, or 1mm stroke crank with no other changes. 1mm crank gives a noticeable mid range gain, but may lose a few hundred RPM (typically).
 
G270 (27.2cc)/G290(30.5cc)--ESP ported, and has head mods performed (squish and combustion chamber cut to accept 2mm crank). This is choice for the 30.5cc engine. More “hole shot” or “corner to corner” low and mid range than the 1mm and stock crank, but typically, the 2mm cranks are not known for making screaming piston port engines, but usually have enough power to gear high, if top speed is what your looking for.
 
The Championship winning porting is the same high quality you have come to trust and expect from ESP, and the amount of detailed work done on each top end kit is not reflected in the low price. All porting is now done with a CNC mill with excellent port time area repeatability, and then finished and detailed by hand to perfection, just like what is done for all of ESP’s sponsored racers.
 
ESP guarantees their workmanship to be defect free, and as reliable as a stock Zen RC engine. If a failure is the fault of ESP workmanship, all damaged parts will be promptly replaced for free. Feel free to call Doug directly at ESP for any questions or possible trouble shooting after the sale. Doug @ ESP is happy to help get you running ASAP.