Run a bike on half cylinders.

[swbarnett]

I was refering to about three or so posts back when somebodys bike was ridden with only two cylinders running, (as per the quote on my post) no mention was made of plugs being taken out.

The plugs were still in place. Just had a blown solenoid so they weren't firing.

I certainly never noticed anything wrong. Not that I pushed it to it's limit anyway.

[pete376403]

There is a major flaw in your theory, without going into it try this:

Next time you have the plugs out of you engine spin it over using the starter motor.

Then try it with the plugs back in.

And notice the cranking speed.

It's not just my theory...

I did install a compression release on my kawasaki F9 (350 single two stroke) for the very purpose of assisting the braking - it was much more controllable than the drum brakes, especially when they were full of water or mud.
Most twostroke singles of that era did have two spark plug holes in the head, the second ususally had a blanking plug installed.

http://www.dansmc.com/comp_release2.htm

Some 1960s and 70s two stroke engine heads have two spark plug holes. You can put a compression release in the extra hole.

The compression release can be used for something else on two stroke engines... an engine brake. This was all the rage in the late 1960s and early to mid 1970s. By putting in the right kind of compression release the engine would act as an engine brake if activated when the engine was running. There were problems with this. If you did not have the right design, the engine could draw in dirt and the hot engine gases could weaken the decompresser spring.

also check out the operation of the jacobs exhaust brake (Jake brake)

http://en.wikipedia.org/wiki/Jake_brake

When the accelerator is released on a truck, its forward momentum continues to turn the crankshaft and compress air inside the engine's cylinders. When the crankshaft passes the top-dead-center position, the compressed air in the cylinder acts as a spring and pushes the piston back down the cylinder, returning the energy to the crankshaft and pushing the truck forward. Little of the energy absorbed by compressing the air is lost, so the engine does not effectively aid in slowing the truck....A compression release engine brake uses an extra lobe on the camshaft to open a second exhaust valve at the top of the compression stroke. The stem of this valve telescopes during normal operation so the valve remains closed, but is locked at full length by a solenoid when the engine brake is engaged so that the valve opens as directed by the cam. This releases the compressed air in the cylinder preventing it from returning its energy back to the piston and accordingly, the vehicle speed is reduced.

While that refers specifically to four strokes, the principle is the same - by releasing some of the air inside the cylinder, the "spring" effect of compression is removed - just the same as running some cylinders without a spark plug.

[TygerTung]

You still have to draw air in and out of the cylinder with the spark plug in, PLUS you have to compress it.

I would suggest that running a CBR250 with two cylinders, IF you can get it to start, will be MUCH slower than a 125.

[breakaway]

A compression release engine brake uses an extra lobe on the camshaft to open a second exhaust valve at the top of the compression stroke. The stem of this valve telescopes during normal operation so the valve remains closed, but is locked at full length by a solenoid when the engine brake is engaged so that the valve opens as directed by the cam. This releases the compressed air in the cylinder preventing it from returning its energy back to the piston and accordingly, the vehicle speed is reduced.

/breakaways' head explodes

[.produKt]

LOL!!!! @ above.
Can smell it from 'ere :P

I have carefully read thru the forum (Tui moment), and noted that no-one pointed this out.

You could just remove a lead, BUT, all that mass of the unburnt fuel compared to the mass of burnt fuel will damage something.

And also, the unburnt fuel\air mixture would bypass the piston and contaminate the oil, (assuming that not all engines have perfect compression!)

Just my 2c

[scumdog]

LOL!!!! @ above.
Can smell it from 'ere :P

I have carefully read thru the forum (Tui moment), and noted that no-one pointed this out.

You could just remove a lead, BUT, all that mass of the unburnt fuel compared to the mass of burnt fuel will damage something.

And also, the unburnt fuel\air mixture would bypass the piston and contaminate the oil, (assuming that not all engines have perfect compression!)

Just my 2c

Well worth $2!!

SO, so true!!

(And I tried to say that earlier to the non-believers bit oh no, they knew better)

[mark247]

Doesn't the fact that the crank is pulling the conrod instead of the conrod pushing the crank mean it can cause wear or crack the crank or something? I was told this by someone and i dont know if its true or not...

[AllanB]

If your plug is out you will also be open to any shit flying through the air going down there.......

[.produKt]

Think he's given up on the idea yet? lol