Comments on: JJ2S X4 500 – 4 Cylinder 2 Stroke Concept Motorcycle

By: Brandon McCanna

Brandon McCanna — Tue, 13 Oct 2009 01:26:52 +0000

Hey, My name is Brandon, and a couple months ago I designed an X motor of my own, but it is an automobile application. If you’d like to lend a hand to the next supercar feel free to email me and I’ll give you the details. Brandon_McCanna@hotmail.com

By: Brian

Brian — Tue, 22 Sep 2009 15:04:43 +0000

Nice concept and design except why is the exhaust not set up with exspansion chambers? If it is a true Two-stroke engine it needs to have these!

By: Big Sven

Big Sven — Mon, 27 Jul 2009 12:45:40 +0000

I’ve not delved deeply as of yet, but the X-4 does resemble the ill-fated British Lottery bike of the 60’s, the entry sent in by an ex-RR engineer, loosely-based on a design of a top-secret 24 or 48-cylinder 2-stroke engine RR were making for the Dam Busters, so they could haul the 10 ton bombs up a bit higher. Secret, for Beaverbrook had banned any development other than Merlins, and the RR-engineers risked a firing-squad! This is also why the Whittle engine was delayed, without Beaverbrook we could have had Spits with jet-engines during the Battle of Britain! (Westland Whirlwinds, actually, a little-known twin-engined single-seat fighter that was rumoured to have been designed around a proposed smaller version of the Whittle engine). The secret RR engine was said to have rigid conrods, integral with the opposing, minimal, pistons – and thus very light – and the crank span like a camshaft, moving each piston unit to-and-fro, thus the internal friction was minimal. Much like a ‘Scotch-crank’, but better. The only engine they made ripped propellers to bits when the throttle was opened, so rapidly did it pick up, several 617 guys (who I knew) witnessed this. It was a pneumatically-operated, blower-fed, sleeve-valve, and no bigger than a Merlin.

The winner of the lottery for the ‘people’s racer’? BRM, I think, the car people, and it was to be made by Velocette, I think. It was never made and the money dissappeared. The X-4 bike was laughed at. It seems the RR-engineer was making a bike himself, at home – it was seen by a neighbor just before he moved – but, when he checked a few years later nobody knew what happened to the bike or the engineer.

By: Andy J

Andy J — Wed, 27 May 2009 20:46:49 +0000

You do not need reed valves for two strokes any more. they do and have been fuel injected for many years.

By: Dave

Dave — Sun, 26 Apr 2009 11:17:03 +0000

Check out the radial four aero engine at http://www.zoche.de.
This is a 2 stroke diesel (horror) with huge potential, but I think stalled by the aerospace homologation costs. But don’t let the diesel bit put us off….
They use simple piston ports, dry sump crancase with no air or fuel breathing through, so its clean.
They have a high geared turbo blower to feed air at low revs. This doubles as a compressed air starter. It has no starter motor!!!
A normal turbo feeds air at high revs so no spannies. That said once its started the gas flows alone should keep it running. Outgoing exhaust can drop the cylinder pressure below ambient so some air will naturally flow in. I guess not enough for clean running – hence the blowers.
They have fixed piston ports and because mega reliabity is an aircraft must-have it only revs to 2,500. But diesels give a flat torque curve and can go to 4000. The Zoche gives 150bhp from 2.5 litres running at 2500rpm. If it was revved to 4000 it should be close to 250bhp = 100 per litre. This is all with simple mechanical fuel injection.

Now add in some modern common rail injection and electronics and who know how much power it could make. Having no crankcase pumping losses or narrow power bands to worry about its probably capable of doubling the bhp of the 4 stroke with the same capacity. Modern car diesels are close to 100bhp per litre so who knows what an automotive Zoche could be capable of.
Now add some inlet reed valves, exhaust “power valves” (a la RGV or Elsie) and burn petrol. The biggest issue would be the huge radiators needed to keep it cool.!!!
Mechanically all four con-rods are mounted on a single crank pin. Its like two Ducati V twins back to back. There is no master rod like a 4-stroke radial. There will be zero vibration and four firing pulses per crank turn.
At 4000rpm it will be firing at the same rate as a 4 stroke four doing 8000. In basic tune this drops into Yamaha Diversion 900 and Honda CB100F territory. But with no camshafts no carns no poppet valves its less complex and lighter – even with a turbo.

A bike could be light weight and amazingly efficient so would need to carry less fuel.

I want one. Has anyone got a few £million do develop a working product.