electric start voltage drop

I have a 79 kz1000st and am having problems with the starter (relay) i have done every test i can think of and still no luck i know that the relay is good because i can jump the power lead off of another hot wire and it clicks fine but when hooked up..nothing, I have checked the lockout switch on the clutch..it was good the ignition switch and the start button all of them seem to work but when i test the power wire for the relay when i pull the clutch and push the start button i only get about 10 volts and no click but like i said when i hook it to another hot wire it clicks fine could this small voltage drop be just enough to not engage the relay?

Check your electrical connectors for corrosion. Any green crud is resistance and lower current flow to components.

Another place to but a replacement starter solenoid(the thing you call a relay) would be to take your old solenoid and visit the nearest riding lawnmower shop. While they may not be an exact replacement, with a little wiring it will work fine. The motorcycle dealers want about $100 for a new solenoid while the mower shops only need about $15.


The smaller wires connected to the solenoid energize the coil and cause it to pull in the heavy contacts putting current to the starter motor to start the engine.

All large gauge wires must be clean and tight to conduct the high current needed to start the motorcycle.

I've tried a second relay,not a new one but a spare i have layin around and still no go, im pretty sure its not that because thoes smaller wires your talkin about.. if i unhook the one thats not the ground and hook it too like a tail light wire or something else that has 12 volts it will click and the bike will start, i think like you said i just have too much corrosion to get 12 at the relay but i am getting 10 volts to it power wire i figured that would be enough to atleast make it click

I'd take apart the right pod assy. on the handle bar and clean the start switch as this may be why the voltage is low. Check all plug in connections as more than the starting circuit may be affected(turn signals,stop and tail lights and headlight).

well i fixed the starter, not sure what i did but i was investigating my fireing problem and got tired of kicking it over so i tried the electric start and it worked! must have been a bad connection that i moved around when messin with the coils, im still having a problem with them though, no fire on 2/3 cyinders, coils are new i believe along with plugs and wires but im yet to do any real testing to see what it could be. I did go over every single electrical connection with contact cleaner and and dielectric greese.

I have a very similar problem with my 82 kz750 spectre. After some tests, I'm finding a 7.5vdc drop at the starter motor :S . I've gone over all the connections I can access, there isn't bad corrosion anywhere and my relay (solenoid) seems perfectly fine.

My next step will be to take apart the start/kill switch as MFolks suggests. But here is the confusing part, I figured I would cheat by jumping the starter motor directly with a 12v battery... the motor doesn't crank any faster than it did when I assumed the problem was just a voltage drop issue via bad ground connections .

I was thinking this means a bad starter clutch because the starter bench tested fine. (although a bad star. clu. doesn't explain the v-drop)... buuut when I bought the bike in Jan. the previous owner started her right up with no problems (with a jumped battery). The only variable I can think of that has changed since Jan. is some added engine oil and dry gas in case there was some condensation in the tank.

fyi, If this matters, there is what appears to be an ignition coil mod installed similar to the one outlined on wiredgeorge's website: WG Ign Coil Mod

p.s. - I'm new to kzrider.. so I apologize if I should have started my own thread instead of posting here.

is it at the fat cable at the starter or is it in the wire for the relay switch? mine was at the switch i just cleaned all connections and greese with dielectric, if its at the cable at the starter motor im not sure what it could be maybe a relay switch problem or just bad connection from battey to relay or relay to starter or just bad cables or it could even just be a weak starter

I got 3 cranking volts off of the lead on the starter when grounded directly to the starter housing. It was a no-brainier telling me that 3 volts isn't enough to turn the engine over... but 12 volts directly from a battery hooked up the same showed no difference in cranking speed.

All connections were cleaned and checked... your right about the cables though, I haven't even bothered to check the resistance through the cables yet.

It's not uncommon to have a cable develope corrosion inside the insulation. A good battery shop can make you up a new set of cables, just bring your old ones along for length and terminal lug size.

8 gauge welding cable(or 6 gauge if they don't have 8)is a very flexible high current capable conductor that will more than meet your needs.

Yes welding cable is great I use it on my jeep, reason being that its made of a more pure copper or something it when you crimp on a terminal (with the right kind of crimpers) all the strans weld themselves together and make for a very strong connection thats good for vibration although i havent switched my bike over to it yet since i havent had any problems from the OEM cables yet

MFolks wrote:

8 gauge welding cable(or 6 gauge if they don't have 8)is a very flexible high current capable conductor that will more than meet your needs.

Great idea! I will deffinatly be doing that desipite the outcome, good conduction is always a plus amd I should be able to get a hold of that pretty easily...

However, it still doesn't explain why the bike cranks so slowly even when the starter is hooked directly to a battery. Any other thoughts on that?

I would guess a faulty stater Im sure they can get weak over time Ive had it happen on cars before, another thought, were you using the cables when you jumped it from the battery or another cable? if you used a differant cable then i would say it has to be a weak motor, I think all the starter clutch does is let if free spin when it running i dont see how it could make it go slower, if it was slipping it seems like it would spin faster if anything