Generic bike question/not a trader!!! lol

Alright fellas, been a little while. The police 1000 is running alright, needs a rebuild, leaking some oil but otherwise, running well, thanks to the folks on here. I just picked up a cb500 bobber lookin thingamajig. Heres the issue. Definitely not all cylinders firing. I know the carbs are clean. Has new plugs. Coil cables are good. Noticed that pipes 1 and 3 were warm. 2 and 4 were HOT. This does not coincide with the coil set up as far as one coil being bad, one on each. After doin a lookup with the pros here at KZR, I switched two coil cables. Then 1 and 3 were HOT. 2 and 4 were warm. Since I did this in the dark I could see flame coming out the headers, no mufflers currently. When the flames shot out, the engine surged for a second, could feel it as I was sitting on it.

Is this timing?

Any suggestions? Seems like this should be something obvious that I am missing cuz the old noggin is mush after a day of workin on the bike. Thanks.

And no, I'm not a trader. I will always have that damn KZ 1000p. Love that beast.

No it's not timing. You've got a bad coil.

kzcsi

I've been workin on this for days now and feel a little closer to a solution. I've been reading quite a bit and it seems WG's coil mod may be in order. I'm getting 10.95 on both the coils. The strange thing here, is that we ran the bike for a few minutes, and the charge on the coils came up to 11.5. Once we turned it off, the readout showed it was dropping slowly. My question is, do you think the mod will fix this, or is it an issue of needing new coils? The fact that each cylinder has taken turns not firing has me loopy. But I think points to electrical. Noy much on this thing, front and rear light. Will be checking wires from points to coils in a couple days for loose or bad wires. Everything on here "appears" pretty new.

I think it would be worth doing the coil mod which is only going to cost about $10 before spending a bunch of money on new coils.
Is the battery charging? 12V at idle and about 14V or so at 3,000rpm? Also wondering about the condition of the points and how do the spark plugs look ? Are they sparking at all on the effected cylinders or perhaps just weak spark? Are they sooty as in poor combustion ?
I had a CB500 years ago. Very similar in mechanicals and electricals to the kz's
A total wiring check is probably a good idea.
Good luck

Solve the most obvious symptom first and do the coil mod as JR suggests in order to get that all important full battery voltage to the input of both coils. Its cheap and these old bikes need it (don't ask how I found out :blush: ).

If the symptoms remain the same, then go for new coils. I lost almost half a summer's riding troubleshooting used coils I had bought for the scrap yard. :pinch:

Best of success.

all the coil mod in the world is not going to help you.
you allready got your answer.
if first 1 and 3 were warm and 2 and 4 were hot then you switched and then 2 and 4 were warm and 1 and 3 were hot, you have a bad coil.

the coil mod is a good idea but it will not solve your problum.
you can get a new coil here

www.z1enterprises.com/

If similar to Kaws, one coil fires cylinders 1 and 4 and the other fires cylinders 2 and 3. So the pair of plug wires from one coil would go to cylinders 1 and 4, and the pair of plug wires from the other coil would go to cylinders 2 and 3.

Maybe I'm misreading this, but it seems one of your coils is attempting to fire 1/3 and the other 2/4.

Have you tried connecting the plug wires from one coil to 1/4 and the other pair to 2/3? If nothing happens, reverse the coil connections so that the prior coil firing 1/4 will fire 2/3 and the prior coil firing 2/3 will fire 1/4.

Is the ignition wiring diagram available?

Good Luck!

Here's a CB500 wiring diagram showing one coil fires #1/4 and the other fires #2/3.


CB500 Wiring

True to form, you guys are champs. I'm looking at pickin up some coils and will be going through all connections in the next few days. Will update. Thanks!

Has an ohm check been done on the primary and secondary windings on each coil?

Would assure correct connections from timing trigger (points or electronic ignition) to coils -- believe wire from right side of points goes to primary side of right coil feeding plugs 2/3, and wire from left side of points goes to primary side of left coil feeding plugs 1/4.

Would also check for electronic leakage in plug wires and caps (spray water mist over wires with engine running in dark garage, and watch for fireworks show).

As known, perfect replacement coils will not resolve improper connections or bad plug wires/caps.

Hoping for you a quick, easy, inexpensive fix, and if possible without having to replace coils.

It's possible but unlikely that both coils would fail simultaneously.

Post edited by: Patton, at: 2007/11/07 17:34

Post edited by: Patton, at: 2007/11/07 17:35

Spent most of the day foolin with this thing.took a lot of measurements with the multi meter and so on. Of all the things that happened, I have one question. The battery on this thing got low. I know why and thats not the issue. I had to jump the bike from a non running car. I noticed, that one of the coils got warm / hot. Now I know thats normal. but shouldn't it have been both? Thats it, thats all I got. lol. Delirious.

So I found something about the coils on the bike. They apparently are not made for 4 cylinder bikes. Saw them on jc whitney and thats what it says. www.jcwhitney.com/autoparts/ItemBrowse/c...NTRY_ID:100000140067

Good lookin but wrong damn part. which may explain the weak spark. seems like new coils are damn expensive. Anybody aware if coils are interchangeable? I would guess they are, assuming ohms match and connectors and so on. Anyone?