27.2cc Zenoah Engine 4.25+



some of the thing,s that can be done to an engine,and why.

This custom-built 27.2cc Zenoah G260RC engine, available exclusively at DDM, offers simply amazing performance and legendary Zenoah quality. 27.2cc's of modified and fully ported power. 34mm bore, 30mm stroke. Get the high-revving benefits of a modified G260RC together with the increased low-end grunt from a longer crankshaft. Aprox 4.25+ horsepower, and 5.5+ horsepower with a tuned pipe. Available in black or chrome, and with or without inner clutch. DDM has taken the hassle out of getting a top-quality modified Zenoah G260RC-based 27.2cc engine - we've custom built them for you. The engine comes fully assembled and ready to bolt-on.
So where does the power come from? We start with a brand-new Zenoah G260RC engine (34mm bore, 28mm stroke - 25.4cc). This is the largest bore Zenoah has available. But we want more displacement for more power, while still keeping the high-quality Zenoah cylinder assembly! So, the stock 28mm crankshaft is removed and set aside. We want a longer 30mm crankshaft for increased displacement and power! But the stock Zenoah 34mm G260RC cylinder does not have room for the long 30mm crankshaft, so ESP has machined out the proper spacing. This is a more efficient and reliable solution than stacking gaskets to achieve the needed space, as there is proper spark plug clearance, the piston ring remains in the well-plated area of the cylinder, and the ignition coil remains properly gapped to the flywheel. The squish band is cut so there will be .020"-.025" of squish (using the stock .020" cylinder gasket), and the combustion chamber is machined to get the compression ratio down to 14:1 for running on premium pump 91 or higher octane gasoline. The head geometry is reshaped to the proven standard 'hemisphere' shaped combustion chamber, and the squish area equals 50% bore area, for more efficient burning.
After the ESP cylinder spacing modifications are complete, ESP then fully ports the engine. ESP completely tears down the engine and spends hours, cutting in great detail, the porting that will have you grinning from ear to ear. Detail like this is almost impossible to do on a milling machine - even a CNC milling machine.
Compare this to other offerings on the market and you will quickly see that DDM and ESP put power in your trigger finger without putting a huge dent in your wallet. Portwork includes:
1) Cylinder precision ported (exhaust, intake, and transfers enlarged and reshaped).
2) Polished exhaust port (for smooth flow and low carbon build up) and superb rough finish on the intake, cases, and transfer tunnels for better gas/air mixing.
3) Resurfaced intake, exhaust, and spark plug gasket surface on cylinder to insure no leaks.
4) Perfectly matched cylinder transfer tunnels to cases and case gasket matched.
5) Case porting to insure better flow into the transfer tunnels.
6) Cylinder skirt work to aid flow into the transfer tunnels.
7) New gaskets and piston c-clips.
8) Easy to read carb tuning instructions to get the most reliable power from your engine.
9) E.S.P. logo etched into side of crankcase.
I was looking at that engine until my bike was stolen - the problem with a rooted engine is that of durability...

Unless the changes are engineered in from the start you can get reliability issues.

for example - the Rootes Group 1592/1725cc engines ran from 62 to 85HP - the only difference between the two looks to be a different head and induction manifold ... up until you find out that virtually everything on the 85 hp engine was changed - and that 'designed in' strength allowed a final road output of 107hp (Alpine H120) and racing output of 160hp which for an engine designed at the back end of the 50's is pretty good. I know these engines are indestructable from experience.

Its worthwhile looking round this and other forums whether other users of this engine rate it

Jemma xx
Jenna there is 'designed in' strength already in on most well build Japanese and Taiwanese engines like Tanaka and Zenoah compared to some of the cheap chinese build bicycle engines out there. However a high reving rooted engine as you say, also has it's own reliability compromised. In this case we don't know which would be more reliable. The proof is on the pudding. But that modified Zenoah sure sounds like a lot of fun.
Just a quick question, was your stolen bke that one with the sprocket mounted on the disc brake and with a custom made expansion exhaust chamber and a Delorto knock-off? If so, Hope you get the ******* who stole it and get it back.
Just a couple of questions about the engine....First what kind if $$ are we looking at?
Is there a pic of the zenoah....Does it have the needed gear reduction or would a tranny be needed to work to get the proper gearing?...Also, what is meant by "rooted".
http://www.davesmotors.com/store/product993.html g260 Zenoah 6+hp $699

http://www.davesmotors.com/store/product1674.html g260 Zenoah 4.25hp $425

http://www.davesmotors.com/store/product1610.html CY31RC ChungYang4.5+hp $399

http://www.davesmotors.com/store/product1295.html GP460 4.2+hp $255

And I think this last one is a good deal, 46cc so it has it easier; and it's peak hp is at only 11,000rpm, 2.3lbsft torque not bad.

The stock g260 for comparison cost $214 + $5(w/clutch) and has 3 hp, 14000rpm, 1.4lbsft.torque
Nice....if there was a gearbox to gear it down it looks really good...would a gearbox like on the tranny thread work?...if so which one would be the recommended tranny?
The 6+ HP would be insane!
:cool:IMO, with max hp and torque at 11,00rpm and 8,000rpm, the STATON 18.75:1 box, when used in conjunction with NuVinci hub, is the only transmission that would be able to successfully harness and make full use of ANY high-rpm engine.

Besides, both components possess excellent long-term warrantees.

No other transmission I've researched comes close.

I might be wrong, but I'll post later with stats on theoretical mph/rpm range.s

Waiting anxiously for your figures!.....I am just wondering tho....what does the manufacturer rate the HP of the gearbox and hub at....well, maybe 6 HP isn't too much...Maybe!
:cool:Andy, STATON has a lifetime guarantee on the gears. In its gearbox are 3 gears and their shafts. That's all there is.

NuVinci hubs are rated to handle 95.81 foot-pounds, which is more than a 1600 cc 60hp VOLKSWAGEN engine can produce.:eek:

With 12t gearbox sprocket and NuVinci 36t sprocket, maximum speed in low gear is 5.91 mph at 8,000rpm and 8.13 mph at 11,000 rpm.

Maximum speed in high gear is 20.57 mph at 8,000rpm(peak torque) and 28.3 mph at 11,000rpm(peak hp).