question about spark plug wires and coils

So i started the restoration of my 77 kz650 b1 this weekend. Spent two days cleaning and rebuilding the carbs, so im making progress. my next area of concern is the plug wires. The previous owner covered them in electrical tape after they began to crack, so of course i will be replacing them.

This is my first build, and i am still fairly new to much of this. My dumb question is, if i want to replace the plug wires and coils, do i need to buy some that are designed for the 650? I was thinking to pick up a new set of eccel plugs and coils, but i wasnt sure what the specifications are. Thanks for the help.

If the sparkplug wires are replaceable(check the coils and see if the caps unscrew)you can use 7MM wires available at most good speed shops. Some places sell it by the foot, others sell kits for cars.

If the wires are sealed to the coils, Z1 sells NGK sparkplug splices: www.z1enterprises.com/SearchResult.aspx?...eyWords=NGK%20splice .

Most ignition coils are rated by ohms, some riders use 2.2 to 3 ohms for their bikes, again z1 sells just about any part for these older bikes.

I believe z1 also sells the sparkplug caps too.

Avoid using sparkplug caps with resistance sparkplug wires as this may reduce the spark energy. Use good copper plug wires with the caps and it should work well.

I'd also suggest checking the primary side of the coils(small wire side) for proper input voltages. With the battery fully charged, you should read almost the same as battery voltage. If it's down around 7-10 volts, your bike could benefit from doing a popular relay bypass.

Read up on it at www.wgcarbs.com .

You Got That Right.Bro.

The wires on the '77 KZ650 coils do not unscrew or disconnect from the coils. Ed

May wish to also consider Dyna coils and plug wires from Z1E.

Dyna plug wires include the caps already built in.

Click here for listing > Dyna 3 ohm coils and 7mm plug wires Z1E

Good Luck!

cobura wrote:

So i started the restoration of my 77 kz650 b1 this weekend. Spent two days cleaning and rebuilding the carbs, so im making progress. my next area of concern is the plug wires. The previous owner covered them in electrical tape after they began to crack, so of course i will be replacing them.

This is my first build, and i am still fairly new to much of this. My dumb question is, if i want to replace the plug wires and coils, do i need to buy some that are designed for the 650? I was thinking to pick up a new set of eccel plugs and coils, but i wasnt sure what the specifications are. Thanks for the help.

Z1 sells new replacement OEM style four Ohm coils for $36 each which is a steal. Make sure to get the correct resistance coil.

sounds great. I checked if the plug wires disconnect, but you are right, they dont. Is there any easy way to tell what ohm wires are on there now? The whole electrical system is quite a mess. It looks like half of the harness is jimmy rigged and i am getting a strange electrical buzzing sound coming from the left panel area. Any recommendations? It would be nice to find an entire electrical replacement kit.

Ignition coil resistance can be checked using either an analog or digital multimeter.

Disconnect the primary(small wires) side of the ignition coils and with the meter set on OHMS and the lowest range(usually X2) put the test probes where the wires came off of.

The meter should indicate 3 OHMS or less for the coils.

Sparkplug resistance wires are usually a carbon string surounded by insulation. It tends to limit the RFI(Radio Frequency Interference) you can hear on some radio's by the snap and pop as the plugs fire.

If you upgrade to copper sparkplug wires,it might be noticeable.

cool thanks. Will try to do that next, although i shouldnt expect a good reading considering the condition of my harness and improper battery that came with the bike. Might be a good idea to just replace the coils as well as the wires. Thanks for the help!

Next up is to repair that harness. Might just buy a whole new one. I didn't realize how much work this bike needed before i bought it. It will be nice though when its done. Always wanted a KZ since i was in high school, so its worth it. So far (since this last weekend):

-cleaned and rebuilt the carbs
-new ignition switch (old one used a screwdriver)
-picked the lock of the tank (since it didnt come with a key)
-stripped rust from inside of tank (still soaking)

next i need to find the rubber tubes that go from the airbox to the carbs. Need to fix the petcock, its gummed up. Fuses and wiring harness, and so on. Maybe the engine will fire up next week. Does anyone else's kz650 have a center stand that is just about impossible to get up? I'm not weak, and it is impossible for me to do it. It took both me and my friend, he picked up the rear as i kicked up the stand.

also, i noticed that my exhaust is crossed. 1 and 3 go to one side and 2 and 4 go out the other. That is not stock, correct? My 650 is a 1977 b1

Z1 enterprises will have the carb to airbox rubber tubes. Your exhaust sounds like is is an 650 SR exhaust system. Pics would be great if you could. The bike is a pain to get up on the center stand if your not used to it. Usually when iu put mine on the center stand, i use my foot to hold the stand down, and lift up on the frame right behind the side cover.

Unless you have a really good Ohmeter, you won't get accurate data at ten Ohms or less. You have to subtract the test lead resistance from the reading.

If you have a points ignition, I think the stock coil is four Ohms. The electronic ignition systems used lower resistance coils like three Ohm range.

Could try rolling rear wheel up onto a wooden block just before lifting bike onto centerstand.

This technique works very well for my KZ900-B1 LTD, allowing one person to easily put bike onto a centerstand from a standard model.

Maybe it will also work with your bike.

I use a short length of 2x12. But a slightly thinner or thicker piece might be better for a different model bike.

The pic is just before rolling bike up onto the wood block. Once on centerstand, the block may be easily removed or simply kicked away, leaving rear wheel slightly suspended off floor.

Credit and thanks to Z1E's Jeff Saunders for this tip.

Good Luck!