Why does my bike need a battery?

[DarrenSV650S]

I've got a TZR250 that has been stripped down for the track (not by me). There is no charging system, so it just runs until the battery runs out. It has a kick start. I'm guessing it is using the battery to power the spark plugs

So why does it need a battery when some bikes don't need them at all?

[northwind]

Bikes that don't have batteries at all will have a generator providing power to keep it going, yours has no generator so the battery does the same job. Total loss, it's called.

[DarrenSV650S]

Ahh. Do you think it would be possible to fit a generator?

[the_lone_wolf]

Originally Posted by DarrenSV650S

It has a kick start. I'm guessing it is using the battery to power the spark plugs

no, once the engine is running it is self sustaining

the battery is there to power the starter motor and smooth out the signal from the regulator / rectifier, on a kickstart bike you can (always?) fit a capacitor instead of a battery to save weight, which is the plan for making my 560SMR illuminated

[DarrenSV650S]

Originally Posted by the_lone_wolf

no, once the engine is running it is self sustaining

the battery is there to power the starter motor and smooth out the signal from the regulator / rectifier, on a kickstart bike you can (always?) fit a capacitor instead of a battery to save weight, which is the plan for making my 560SMR illuminated

So why does the battery on mine run out?

[jambo]

Originally Posted by DarrenSV650S

There is no charging system, so it just runs until the battery runs out.

Originally Posted by the_lone_wolf

no, once the engine is running it is self sustaining

One of these two statements is correct

In normal operation the generator will provide all the power the bike needs to run, plus some surplus for recharging the battery. If the generator has been removed to save weight and losses on turning the crank then the bike has no method of generating it's own electricity, and when the battery is dead so is the spark. You should be able to retro-fit a generator back on, but it depends on how it was removed, and how much of the wiring is AWOL how easy this will be.

Jambo

Both statements are correct, but not at the same time!

A battery, or a generator, is needed to power the sparks/electrics. You can have both, either one, but not neither,

[jambo]

Originally Posted by simesb

Both statements are correct, but not at the same time!

A battery, or a generator, is needed to power the sparks/electrics. You can have both, either one, but not neither,

Quite right, have just re-read my post and seen that it might imply one of the statements couldn't occur, rather than that they couldn't both be correct at the same time.

Jambo

petrol engines require a battery to power the low tension side of the ignition. On race engines you do away with the heavy generator and run a small battery on a total loss system. This is why when you have a poor battery the engine misfires.
Diesel engines will run completely mechanically and only need a battery to start them.

[the_lone_wolf]

Originally Posted by shifter

petrol engines require a battery to power the low tension side of the ignition. On race engines you do away with the heavy generator and run a small battery on a total loss system.

i'll give you a tenner if you can find the battery on my KTM