Two Stock CB750 engines, One Transmission?

[Angel And The Wolf]

Originally Posted by Grinder74

With a jack shaft setup you could put one engine in neutral at cruising speeds for better economy.

Or: with Engine Cylinder Deactivation Engine-Cylinder Deactivation Saves Fuel | J.D. Power Cars
and Free Valve technology

https://www.youtube.com/watch?v=OZWeNPi2XkE

I could have the two engines simulate a 500 CC engine for cruising economy:

[Angel And The Wolf]

Here's the diagram:

[Angel And The Wolf]

Of course, the Leave Open valve idea would only work if the CB 750 engine is a
Non-Interference engine. Otherwise the system would have to close the valves as the piston approaches TDC. Still, the valves on the deactivated cylinder could remain fully open for most of the strokes. Even without the valve component, the fuel injection cutoff would save fuel, and be much cheaper and easier to implement.

[Angel And The Wolf]

Originally Posted by Grinder74

With a jack shaft setup you could put one engine in neutral at cruising speeds for better economy.

The main problem, for me, is that by de clutching one engine, I lose sync, but since I'm sync'ing them after the transmissions, I will probably change the sync'ing every time I step on the clutches. Looks like I need to join the two engines before the clutches. SO, your suggestion of the Lovejoy Coupler, joining the actual crankshafts, may be the best way to keep the two engines constantly sync'ed, though I don't know how to gain access to the ends of the two crankshafts, one on the right side of the crankcase, and the other on the left side of it's crankcase. Maybe I can put a shaft between the two Primary Chains:

[Grinder74]

Gotcha!

[Angel And The Wolf]

?!

[Angel And The Wolf]

My last diagram may not have been clear. This is the firing order for 8 cylinders firing over the course of 6 revolutions.

[Angel And The Wolf]

This has me thinking. Even with a single 750 engine, rotating cylinder deactivation could reduce the effective displacement to 250 cc for cruising on the flat, or nearly flat, and of course the down slope. (This would work on any four cylinder) If you can insert a wedge between the cam lobe, and the rocker arm of deactivated cylinders, you can keep the valves slightly open, and lessen the resistance a fully sealed cylinder would present to pulling a vacuum on down stroke, or compressing a cylinder full of dead air on upstroke. You would have to have a fuel injection system capable of being deactivated cylinder by cylinder, and single cylinder throttle bodies and air cleaners, to prevent back firing.

[Frank Lee]

You have never looked into how cylinder deactivation works. Now is the time.

[Angel And The Wolf]

Yes, I have. I've also looked into the Koenigsegg free valve system, adaptable to any ohv engine, but that's far out of my budget. There are valve systems that have variable lift controlled by extra pieces between the cam and valve stem. I know that GM's V4-6-8 engine left the valves operating normally, and just cut the spark. I know that in GM's system, they didn't rotate the inactive cylinders, and build up of oil and fuel in the cylinders caused problems. I know that Honda has some V6s that can become 3s at low load, and I don't know of any problems with them, but I suspect uneven wear in the "off" cylinders over time. Rotating through each cylinder seems to be the best way to even out wear,and prevent build up.I will be glad to look into any new material you can direct me to.