cylinder deactivation

[renault_megane_dci]

In my quest to meet the best of both world (FE for cheap) I am contemplating an other axis then atkinsoning a bike engine (GPZ / EX).
I like the concept but :
A/ it needs to be a definite modification (to keep it cheap) and I like my power blast here and then
B/ it might not even match the FE of a regular 250 bike
C/ there are a number of unknown, most worrying of all is the functionality of carbs on a breathing back engine

The other option is to deactivate on the push of a button one of the cylinders of K7 and UP Suzuki SV.
K7 is because they are injected and I believe all is required is not to inject in one of the cylinders.

Then I end up with a 325 engine with a drag penalty.

It is also over geared for its capacity wich is a load booster (pumping losse minimizer)

Do you think it is a worthwhile idea ?

Do you think I need to have the throttle body of the dead cylinder fully open, fully closed or still linked with the live cylinder throttle ?

I believe it might return the same potential than an atkinson EX 500 but with the ability to have the full monty whenever needed.

The Suzuki SV is also a much nicer bike with a higher resale value.
Also, said mod does not need to make my hands dirty.

I can even go crazy and atkinson it (I believe 99 to 07 models have shorter camshaft than 07 to ? models) and add the cylinder deactivation on top of that !

[Frank Lee]

The other option is to deactivate on the push of a button one of the cylinders of K7 and UP Suzuki SV.
K7 is because they are injected and I believe all is required is not to inject in one of the cylinders.

Oh for Pete's sake. Really? We must have 3,000 posts on cylinder deactivation that debunk trying it with a mere injector kill. The valves MUST be deactivated as well.

[t vago]

In order to make cylinder deactivation work via shutting off fuel injectors, you'll need to do the following:

Coat your spark plug electrodes with latinum,
Get a quality motor oil with a tritanium-based wear additive,
Obtain some SeaFoam Plus with Neutronium (tm), and pour the contents into the throttle body with the engine running at 1000 RPM, and
Get some STP Fuel Treatment with corbomite, and follow the instructions on the bottle.

[renault_megane_dci]

Originally Posted by Frank Lee

Oh for Pete's sake. Really? We must have 3,000 posts on cylinder deactivation that debunk trying it with a mere injector kill. The valves MUST be deactivated as well.

Sorry I did not do a search ...
On my way to do it before I ask some more dumb questions about engine dynamics ...

That being said, I'll keep up thinking about the concept in the right direction.

So, there are only two options to disconnect the valves :
- stop the camshaft
or
- stop the relation between camshaft and valves

Anything that has to be phased feels a little to difficult for my DIY approach so it kills option 1.

I have heard about two concept for option 2 :
- slide the camshafts so it doesn't push cam (this needs to be phased too ...)

- have an interface follower with variable volume à la Fiat Twin Air engine.
This one begs for a rocker setup rather than a camshaft directly attacking the valve, so long for the SV engine then.

It does open avenues for Bandit engine though but I am not quite sure the later liquid cooled / injected engine still have rockers.

I have to double check what system is used on big german V8's with this feature.

[wmjinman]

Sounds like some pretty advanced stuff for "do it yourselfers"

[Frank Lee]

I think it is possible; back in the day I tried to figure out how to do it and I concluded it isn't out of reach HOWEVER factory systems seem to be achieving about a 7-10% increase in fe. For the amount of effort to potentially gain- in my case- up to 3 mpg, there is a lot of lower-hanging fruit to go after.

[renault_megane_dci]

Remember I am focusing on bikes wich are known for using stupidly overpowerful engines for their weight.
This might allow for a much higher rate of cylinder deactivated operation than it is possible on a car.

Actually the strategy I am following is mainly to overcome the massive lack of used 250's on the french market ...

[alvaro84]

I have cylinder deactivation on my bike. It's called kill switch and it deactivates one cylinder of the... one

OK, joking aside, I really appreciate those who go this deep

[GreenHornet]

Originally Posted by renault_megane_dci

Remember I am focusing on bikes wich are known for using stupidly overpowerful engines for their weight.
This might allow for a much higher rate of cylinder deactivated operation than it is possible on a car.

Actually the strategy I am following is mainly to overcome the massive lack of used 250's on the french market ...

Just go with a hybrid setup and down size the ICE as much as you can get away with in order to maintain your top end cruising speed! A 72V to 96V system would give you solid performance down low and not add to much cost and weight to the table as long as you use Lithium Iron batteries or a hybrid battery design.

By the time you do everything needed for the cylinder deactivation the hybrid may not look so costly or complicated!

Cylinder deactivation can absolutely be done and does give benefit but you are still utilizing an ICE why not go HEV especially in France heck the majority of your power comes form Nuclear which gives you a big advantage to use electric at least part of the time :-)

[renault_megane_dci]

France is not tolerant to homemade vehicles.

Modifications need to be either invisible or categorized as cosmetics.

I would love an EV bike but I would need one that is available over the counter.
The only 125 equivalent that I can think of are used Vectrix VX1 or Zero Motorcycles which are not exactly cheap.

Anyway, I have to catch up on reading about this injection less deactivation and evaluate its potential FE wise bearing in mind the specificity of bikes and their engines.