bench time (= mechanic time = $) , once the engine is open, might as well be hung for a sheep as a lamb and do the whole innards anyway.
I swear I heard that the UCE bottom end was purposely over built compared to its output.
I think it was SB who said the used "Dump truck" bearings in the thing..
This write up on the UCE seems to allude to some significant bottom end and connecting rod upgrades from the Iron Barrel. So it might just be a matter of replacing the cams. Nigel. And I don't lightening the flywheel is the way you want to go: Like the BSA Goldstar, that would give you high rpm performance and power but at the cost of low rpm manners and the momentum that helps the Bullet power out of curves and slowly wind up acceleration in any gear. Lighter fly.....more shifting and revving, and idling /starting problems . i think most riders interested in this bike wuold like strong pull from the bottom and middle, ower building up from the upper to middle range toward the redline: If they wanted that, they would get a sport bike. . ACEs type of mods can get the slowly winding up power without the loss of the engines defining characteristics. COPIED FROM A ROYAL ENFIELD SITE;The advantages of unit construction are:•fewer external oil lines to leak/fracture•no external drive connecting engine and transmission, thus simplifying maintenance•mounting in the frame is simpler - no need to align engine and transmission within frame•the combined casting may be stronger or lighter - hence more easily used as a stressed member of the frame.The chief disadvantage is that the engine and transmission have different lubrication requirements. In a design where the engine and transmission use a common oil supply, the oil used must take the requirements of both into account. (eg 1972 Ducati 750) Also the gearbox cannot be changed to that of another manufacturer. If different gears are required, they have to fit in the existing unit construction casting.The chief advantage of separate construction is the ease of removing gearbox or engine separately for maintenance, or for complete gearbox replacement, with stronger gears, or more gears, or better spaced gears. Another technology used in the bike is electronic fuel injection (EFI) which replaced the Lean-Burn Mikuni CV Carburetor engine. The EFI better controls the air-fuel mixture ratios at different speeds and riding conditions. A better cooling alloy cylinder, stronger crankshaft and connecting rod, improved oiling and a host of other features are all part of the improved Royal Enfield UCE engine.The UCE 500 EFI was originally unveiled at 2008 Motorcycle Shows in Cologne, Germany and Birmingham, England, although it took until a few years for the news units to hit the U.S. market.The new model is more powerful, technically advanced and more environment friendly. Important to long time RE motorcycle enthusiasts, it also sport an authentic classic look that reflects original British motorcycle styling.The old cast-iron engine which was heavy, less efficient, more space consuming and wasn't very efficient either. The new engine produces 27.5 bhp of power and 41.3 Nm of torque at just 4000 rpm.The lazy nature and the lowly rpm at which the peak rpm is delivered makes for a very commuter friendly experience through slow moving traffic, with the bike pulling with aplomb in low revs and high gears. The UCE powerplant is mated to a five-speed gearbox. The gearshifts are spongy and relatively trouble free for an RE. It could take time getting used to the power delivery and the gearshifts but once familiarized, this motorcycle engine won't let you down. The engine feels substantially refined when compared with its predecessor and transmits just the right amount of vibration to the handlebars. All you need to reach a three-digit speeds is a full twist of the throttle. As well, with the new UCE, Royal Enfield became the first motorcycle manufacturer in India to produce and sell a U.S. DOT and Euro-III compliant motorcycle.************************************************************************************************So it looks like a beefed up solid con rod and crankcase are already in place.. If the 600 sleeve also becomes availble that just kicks it up a notch, and maybe means that the port polishing wouldn't have to be perfect to get very good performance improvement , though that would remain an option . Even the piston would only have to be coated There is probably no advantage to try to get much over 600 cc without a counterbalancer Nigel