Run a bike on half cylinders.

[The Pastor]

Will it be bad for a bike to be run on half its cylinder?

i.e., if i ran a cbr250rr (4 cyl 4 stroke) on 2 cylinders by removing the spark plugs would it break it?

and if it would break it, what would the damage be.

[NordieBoy]

You'd be spitting fuel out the plugholes in a fine mist...

Otherwise no problem.

If you just pulled the leads it'd be more successfull but it'd still be a CBR125RR with an extra pair of pistons to move around.

Make sure it's on video whatever you decide to do

[Ixion]

No fuel mist unless its injected. Spark plugs out means no suction to draw fuel in.

I've ridden twin cylinder bikes for a hundred kilometres and more on one cylinder. No problems, just VERY gutless.

Not a practical thing to do of course unless half your cylinders have crapped out. Though, some late model cars do exactly that - the new Honda Accord V6 runs on 6 cylinders, or 2 or 3 depending on demand etc.

Why do you ask?

[The Pastor]

I was thinking about the less than 200cc ride to the cape challenge, would it qualifiy? Sure the bike costs more than 1000$ but the point is to do it on somthing unsuitable...

[Ixion]

Ah, Youd have to ask the organisers.

Overheating could be a problem, since it's water cooled.

[pete376403]

If you pull the plugs out the dead cylinders will act as an engine brake - the drag of moving air into and out of the cylinder will slow the engine right down. It used to be common (before decent brakes on dirt bikes) to have a decompressor screwed into the spare plug hole of two strokes, and this was used as an engine brake. Leaving the plugs in would be less drag as the energy expended compressing the air (on the upstroke) is returned by the spring effect of the compression on the downstroke. The engine will still run like shit, however.

[The Pastor]

Ah, Youd have to ask the organisers.

Overheating could be a problem, since it's water cooled.

sorry for being a noob, but how would it overheat?

[Steam]

Full marks for cleverness, that's an excellent and hilarous way to qualify for the challenge!

[Ixion]

Cos you're asking it to work very very hard, at low speed (only the two working sylinders would get hot of course).

Working hard, firstly as the numerically imposing gentleman said, pumping air, and working hard with only 125 cc to lug around a bike meant for twice that.

Low speed, cos it's going to be gutless! And thus not much air flow. (I think those motors don't have a fan ? ).

It's unlikely that the designers took such circumstances into account when doing their sums about cooling areas and flow rates , etc

[Steam]

sorry for being a noob, but how would it overheat?

From what the knowledgeable types say, it sounds like it won't hurt it too much, have a go and just keep an eye on the temperatures. Tell us how you get on!

[EJK]

I believe thats how skidMark blew his bike...

[Slingshot]

You'd want to be selective about which two cylinders to choose to disable too. Ideally, the two that you'd want to have firing would be fairly opposite in their cycle...one at (or near to) top dead center and the other at bottom dead center.

[breakaway]

Low speed, cos it's going to be gutless! And thus not much air flow. (I think those motors don't have a fan ? ).

But it is a water cooled engine with a radiator (which has a fan). Will it still overheat?

I believe thats how skidMark blew his bike...

No, that was due to lack of oil and missing a gear change. Apparently.

Apparently.

[EJK]

well for a while he was running on 3 cylinders.... then it "suddenly" siezed lol meh

[Padmei]

ive often thought about running my bike on old oil from the deep fryer mixed with vinegar for a bit of omph what do you think? You know biofuel kind of... would it work?