Helped friend swap 79 kz750 engine into his 82 csr

82 CSR750 motor bolts right in the 79 frame with zero problems, should be the same going the other way. 82 CSR had electronic ignition, 79 had points. Did you connect the single wire coming from behind the right lower small cover, to the coil? And do away with the igniter? If you still have the 82 motor, take the electronic ignition parts (pickup, timing advancer) off it and put them on the 79 motor, they are a direct fit.
You can also swap the stator/rotor/ and cover from the 82 motor to the 79, then it will plug in.

The 82 has BS34 carbs, while the 79 had BS38 Mikunies, plug the unused vacuum ports on the carbs.

My avatar is my 79 750 twin with an 82 motor.

Firstly, thank you both so much for your help. We are going to try to finish this up friday.

The single wire coming from the behind the right lower cover is the stator, right? The 82 motor had 2 wires, while the 79 only has 1. So we cut the 2 pin connector on the wiring harness and just hooked up the one wire. Should I just wire it straight to the coil itself, rather then the harness? There is 2 wires coming out of the coil packs... which place would it hook up too? I'm not near the bike now, so I can't check to see if the wire colors are the same.

We didn't do away with the igniter, as far as i know it's still hooked up. Where is the pick up and timing advancer? beneath the small cover on the right bottom side of the engine? As for the stator and rotor, could you give me the location of these parts, so I can be certain they are what I think they are?

Will the 79 engine run decent with the carbs and intake boots from the 82?

Does sound like vacuum leak/carb problems.

2005jetta wrote: Firstly, thank you both so much for your help. We are going to try to finish this up friday.

The single wire coming from the behind the right lower cover is the stator, right? The 82 motor had 2 wires, while the 79 only has 1.

On my 79, the single blue wire coming from behind the lower right cover is the points breaker wire. It goes to the NEG terminal of the coil.

2005jetta wrote: As for the stator and rotor, could you give me the location of these parts, so I can be certain they are what I think they are?

Left side of engine, lower behind the cover where you access the clutch release assembly.

Does your bike have a vacuum cutoff petcock? If so, you may not be getting any gas.

Yes the petcock does have a vacuum line. If we hook up the wire coming from the right lower cover to the negative of the coil packs, which wire goes to the positive end of the coils?

We do have fuel, loosening the drain screw on the bowls results in spilled gas. Part 'A' of the diagram points to 5 spots. The spot it points to on the right I have a question about... Do we plug that line? Looks like it used to go to the vacuum switching valve. But I don't have that valve anymore with this setup. The bike will rev with starter fluid, then dies.

Do we swap the ignition parts out of the lower right cover, as we did with the stator on the left side? Looks like we have everything else mostly figured out. Do we have to swap out these electrics?

It would be best to use the 82 ignition parts from behind the "right" ignition cover. That one small wire is from the points and "must" hook to the negative side of the coil. The igniter is powered from the coil positive wire, so follow it to find the end of the coil positive wire if you insist on using points.

If you do want to use the electronic ignition off the 82 on the 79 motor, just remove "everything" from behind that small right side cover on the 82 and bolt it on the 79. It only takes a few minutes and it makes everything plug and play. Highly recommended!

Should only have one coil.

Update: We got the engine running excellent. It idles and revs smooth! So thanks everyone for your help. However we have encountered a new problem He went to take it for a ride yesterday, and when he shifts into first or 2nd gear it acts like it's still in neutral. I haven't had time to go look at it yet. I will be going over there tomorrow to see if we can figure it out. Any ideas? Thanks in advance.

C/S sprocket slide off the shaft?

The front sprocket is definitely still bolted on.

Any other ideas?

Can you describe a little better what is happening? When you say it acts like it is still as if it is in neutral, does that mean you never got into gear at all (1st, 2nd, or any other gear)? To get it in second gear, the bike has to be moving or back wheel has to be spinning. Is the shifter shaft/drum sound like its operating. Had a Z1 where the shaft was stripped right where the shifter attaches to it and it would not properly engage the shifter drum to do its job.

It will click down into first just fine. But when you give it gas it acts like it's still in neutral. No change in load or rpms.

Update: So I made time to get over to my friends today to try and finish up the bike. I adjusted the clutch and got the bike rolling. It shifts through the gears fine. Problem now is, the bike doesn't rev right or have any power. Last week when I left his house the bike was revving strong, like new. Now it just bogs and backfires out of the right cylinder. If you let the bike idle it will rev strong once or twice, then it starts bogging again. Have the choke on or off doesn't make much difference once it's warmed up. Feels like it running on one cylinder. You can ride it about 40mph, but it takes a while to get there, and has absolutely no power. It idles like a brand new bike. It starts right up in a split second every time. Just doesn't want to rev. It's very frustrating because the bike ran pefect a week ago. All vacuum lines are connected, it's getting fuel.

I feel like something is wrong with the right side carb... being it's only backfiring out of that exhaust pipe. Could it be ignition? I'm stumped guys. If it's not one thing, it's another. I just want to get this thing running right.