Relay to Cut Off Headlight When Starting

larrycavan wrote:

PLUMMEN wrote:

just keep your bike tuned up and it wont be a problem! :laugh:
i always wire my lights to come on when ever the key is on,i want people to see me coming day or night

They can see Otto in the dark without any lights....He's got a chemical glow :laugh:

[just kidding otto ]

Seriously though..... A properly tuned KZ starts in about a half a revolution of the motor.....So where is the real need for this?

hes learning folks! :woohoo:

bountyhunter wrote:

larrycavan wrote:

Seriously though..... A properly tuned KZ starts in about a half a revolution of the motor.....So where is the real need for this?

It's the design of a wet cell lead acid battery, and the fact that bikes use very small batteries. The starter needs a lot of current which pushes the battery for the internal impedance. As batteries crank out amps, the material on the plates is consumed and gradually falls off and collects in the bottom of the battery (in the sediment tray). These batteries actually are used up based on how much current they deliver and it is not linear. The other thing is as the battery ages (and it's internal impedance goes up) it can stay in service longer since the battery demand during start is less. It basically both reduces battery attrition and also extends the service range since the demand now requires less CCA (cold crank Amps) to start the bike.

So the bottom line is you're saying the battery will last longer.... How much longer do you figure?

AtLarge wrote:

I like it. When I get a rountoit I just might try this. Granted for a "properly" tuned bike it may not be a concern but if you've ever flooded or ran the system out of gas because you forgot to turn the petcock on well... we all make mistakes. I agree with BH. Anytime you can lessen the cranking you might save your butt later. Plus I switched up to an automotive headlight and I know it doesn't take long to suck the life out of a battery when your brake light is stuck on and you don't know it. Seems like a worthwhile mod to me. After all, cars cut the headlights too while cranking.

If you run out of gas.....the factory addressed that with the PRI setting on the petcock

www.impactbattery.com/motorcycle-atv-sco...6&AdGROUP_K=YB14L-A2

Sure seems to me like a more logical solution to a problem that doesn't really exist to begin with...but hey....I'm funny like that :huh:

bountyhunter wrote:

PLUMMEN wrote:

just keep your bike tuned up and it wont be a problem! :laugh:
i always wire my lights to come on when ever the key is on,i want people to see me coming day or night

Yes (me too), but you want the lights OFF when you crank the starter. Lead acid batteries are excruciatingly sensitive to depth of discharge and actually "wear out" based on cranking current out. Worse, the starter is already a severe load so throwing the lights on top is like exponentially worse.

When I got my bike new in 1979, the first battery lasted 14 months (2 months outside the warranty). Must be a fluke I thought. I bought a REALLY GOOD replacement that lasted 18 months. same for next one.

I rewired the bike to disconnect all the lights at startup and I average about 6 YEARS per battery and they are the JC Whitney cheapo ones.

I also enjoy relatively long battery life with rider controlled on-off light switch in right hand handlebar switch gear of Z1 and KZ900.

Am wondering if KZ750 twin is harder to crank over than a four cylinder.

Z1 and KZ900 can actually be started by using hand instead of foot on the kick starter.

Good Fortune!

larrycavan wrote:

bountyhunter wrote:

larrycavan wrote:

Seriously though..... A properly tuned KZ starts in about a half a revolution of the motor.....So where is the real need for this?

It's the design of a wet cell lead acid battery, and the fact that bikes use very small batteries. The starter needs a lot of current which pushes the battery for the internal impedance. As batteries crank out amps, the material on the plates is consumed and gradually falls off and collects in the bottom of the battery (in the sediment tray). These batteries actually are used up based on how much current they deliver and it is not linear. The other thing is as the battery ages (and it's internal impedance goes up) it can stay in service longer since the battery demand during start is less. It basically both reduces battery attrition and also extends the service range since the demand now requires less CCA (cold crank Amps) to start the bike.

So the bottom line is you're saying the battery will last longer.... How much longer do you figure?

In the case of my own KZ-750, the fisrt three batteries (prior to modification) averaged maybe 15 - 18 month life. After mod, at least 5 years. In a couple of cases, I replaced batteries that could still turn the starter but were old enough I wanted a new one. No guarantees, but that's the ballpark I got.

larrycavan wrote:

Sure seems to me like a more logical solution to a problem that doesn't really exist to begin with...but hey....I'm funny like that :huh:

When I bought a new bike and realized over it's long (hopefully) life I would be dropping about $70 on a new battery every year and a half, I definitely had a problem. And this fixed it.

Patton wrote:

bountyhunter wrote:

PLUMMEN wrote:

just keep your bike tuned up and it wont be a problem! :laugh:
i always wire my lights to come on when ever the key is on,i want people to see me coming day or night

Yes (me too), but you want the lights OFF when you crank the starter. Lead acid batteries are excruciatingly sensitive to depth of discharge and actually "wear out" based on cranking current out. Worse, the starter is already a severe load so throwing the lights on top is like exponentially worse.

When I got my bike new in 1979, the first battery lasted 14 months (2 months outside the warranty). Must be a fluke I thought. I bought a REALLY GOOD replacement that lasted 18 months. same for next one.

I rewired the bike to disconnect all the lights at startup and I average about 6 YEARS per battery and they are the JC Whitney cheapo ones.

I also enjoy relatively long battery life with rider controlled on-off light switch in right hand handlebar switch gear of Z1 and KZ900.

Am wondering if KZ750 twin is harder to crank over than a four cylinder.

Compression new is about 160. I have never been able to kick it over.

Compression new is about 160. I have never been able to kick it over.

Must be something about these twins. I can't kick mine over either without punishing myself and the bike. I think I did start it once, maybe, that way.

My old Sears Allstate moped had a compression release lever which helped. I guess that probably would not have worked on this sophisticated machine.

You would think that Kawasaki would have addressed that issue. Or, maybe I'm just a 280 lb wimp.

bountyhunter wrote:

650ed wrote:

My KZ650-C1 has an On/Off headlight switch on the right handlebar control. Could owners of later models just swap their control switch with one like mine so they could decide when the light comes on? Ed

My 1979 has the handlebar mounts that still have the lettering for the light switches but no switches. It would actually be a lot of work to install the older ones (with switches) and wire the switches in. The relay is really an easy installation. The lines are all available near the fuse box. It's also "idiot proof" since it restores stock function automatically after starting.

For the record: having the headlight on with the key is also state law in many places so changing it might get you a hassle trying to register the bike or sell it.

On the 79 750 twin it's just a matter of installing the 78 switch pod and plugging in the on/off light switch to the original wires under the tank. The original plugs are there, Kawasaki just installed a plug in jumper to connect the two wires when they did away with the light switch. Remove the jumper and install the switch pod, easy.

I kick start my 750 twin fairly often, two kicks when cold, one when hot. 170 psi compression and my normal weight is 235 (won't mention current weight).

My typical weight used to be 165. Add the skinny chicken legs to bad lower back pain and kick starting is a real bugger.

Guess I should re-phase my statement, I kicked started my 750 fairly often, last year, when I could actually ride. Haven't had the strength to hold the bike up since I started chemotherapy in March.
Howsomever, the cancer appears to be cured (beat the less than 50% odds of survival), and my last chemo will be a week from next Tuesday, so I'm hoping to ride it yet this year

I'm 5'10'' and 185#. Now that the ambient has dropped and 50W still in the crankcase there ain't no kickin for me.