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Hello Everyone,
This is my first post on these forums and I hope you can help. I have owned and worked on Japanese motorcycles for the last 6 years or so but have always kept things close to whats in the manual. I'm still pretty green still but eager to learn.
I recently bought a non running 1977 KZ650 B that's pretty heavily modded. It's been beefed up to 738cc, has performance cams, Mikuni VM 29 smoothbores, oil cooler, a Dyna III electronic ignition and some other goodies.
The bike was sitting for 10 years so the first thing I did was clean all the carb bits in an ultrasonic dip,blow em out and rebuild them. I was hoping that she'd fire right up but it took some effort to start the bike and it kept backfiring through both the carbs and pipe. I got it started and it smoothed out a bit when running at higher rpm but it couldn't go under 2000rpm without backfiring. It has new plugs and I'm getting spark in all 4.
I found the plug wires may have been jumbled and reset them to what I found on the forum (that the left coil should be 1&4 and right 2&3. Is this correct?) after switching them I couldn't get the bike started at all. I have attached some pictures of what I'm working with. I'm not sure what kind of coils these are. Does it matter which individual line goes to which cylinder? Any incite would be greatly appreciated

One coil fires cylinders 1&4; the other coil fires cylinders 2&3. The engine uses the wasted spark approach, so both spark plugs attached to one coil fire at the same time. Because of this, you can switch wires between 1&4 with no problem and you can switch wires between 2&3 with no problem. You cannot switch wires between 1&2, 3&4, etc.

If the engine ran fine at high (or any) rpms with the coils hooked up the original way then they probably were hooked up correctly. You should be able to trace the wires between the ignition system and the coils to see which wires control which coils. Ed

Check the valve clearances.
Steve

Was it your bike when it was parked? If not, don't assume it was running correctly no matter what the PO says. There is trouble shooting info available for download from Dyna. I would suggest that you do static timing to make sure its close to on. Also, guys tend to forget that even though the spark is electronic the advance is still mechanical. Take the time to disassemble, clean and lube the mechanical advance. If it is hanging up it will mask itself as other issues. But like Steve said, check your valve clearances first as incorrect clearances can damage things permanently and cause more time and money spent.

Thanks guys, This gives me a good place to start. The bike was not mine when it was parked so who knows whats really going on. I'll check the wires that run to the coils first then the valves. This may be a silly question but will the cam or cylinder mod change on this bike change where I want my valves set (is it different than the 650 manual) ?

kaw-a-holic wrote: Was it your bike when it was parked? If not, don't assume it was running correctly no matter what the PO says. ....

Times 1000 !!! lying bastardos