1982 KZ750N build

Here is what I got so far.


I have a few questions, I got everything together and ready to go. On startup all I’m not getting anything. Just every once and a while it backfires. Sometimes through the intake and sometimes through the exhaust. Could this be because I don’t have the dyna s timed correctly? Or is this a cam chain issue?

Second I would like to get rid of all the unnecessary things on the original harness. Specifically the reserve lighting device. From what I remember it would run without it. So how do I bypass it to get rid of it to make more room for in the battery box?

Thanks!

Are you running an open exhaust and what was done for the carb jetting?

BTW, the photo seems to show your forks on backwards.

Right now I’m running with open exhaust. And I bought the carbs refurbished from someone on eBay. They were really well done. Not sure what jets are in there. Also Ik about the forks. I can’t believe I missed it. Not sure if it makes a difference but I had the 1-4 coil in the right side of bike instead of the left. Meaning I also had the coil plugs on the opposite, I guess. All that matters now is that I got her to sputter this morning. And with a little help of the idle screw I got her to idle. A very rough idle that is. I assume that’s due to the exhaust and maybe jetting. Last thing, I’m kinda worried about what you’ll say.... on the carbs. Carb one has a what I assume is a vacuum nipple. It doesn’t have the rubber cap on it and upon cranking I am noticing that it’s blowing or pulsing air. Is that supposed to be capped? And is it not supposed to be blowing/pulsing air? Also last night when I was having difficulty starting and all I was getting was backfire, I noticed some of the backfire was coming through that nipple. Blue flames.:huh:

Thanks!

Are your valves adjusted correctly?

Leaving the vacuum ports open will create a wickedly lean mixture. Typically, three of them should be capped, while the port on the number 2 carb is usually connected to the vacuum port on the petcock (fuel valve) via a small vacuum hose.

Edit: I see that your bike has the Clean Air System, but it appears to have been removed. Two of the vacuum ports would have been connected to that. It is not a good idea to leave the tubes to the reed cages open. The best way to deal with them is to thread the ports in the head and block them with little threaded plugs, then replace the caps with block off plates. Some folks install the plates without plugging the passageways. Still others just hook the two reed cage covers together with a short length of hose.

I would first like to thank all those who have helped me this past year. Yall’s help has been invaluable. I am so glad I have come this far, and I am happy to see the results.

So I just went to go plug the holes and now it really revs nice. Not perfectly but better than before. Though when it would rev after I back off the throttle it dies. Not sure why. Maybe insufficient gas or something. It could be the dyna s timing. More than likely, both the inconsistent reving and the dying after reving it and going back to idle has something to do with the jetting. I’ll try and see what’s on it later this week. As far as I can remember I couldn’t see any markings on the jets.

Would it be stupid to buy those jet kits that come with drill bits? That way I can just drill the jets to size I want.

Last thing, I was noticing that all 2-3-4 exhaust pipes where hot, except #1. It was slightly warm but not nearly as hot as the rest. I’ll mess around with the timing plate to se if that clears it up.

Thanks!

I believe so. I timed the cam myself. And had a professional do the shims.

So right now it is starting. Not sure why it wasn’t before.

On the smaller fours (400 up to 750), the right side coil fired cylinders 1 and 4. It should have a black wire going to it. Most of the larger bikes had the coils on the opposite sides.

It doesn't matter where the coil is physically mounted, obviously, but it's easier to troubleshoot when everything is the way it came stock.

I don't think that messing with the timing will affect the one cool cylinder, as any timing change will affect all four the same. Typically, one cool pipe is the result of a serious difference in the fuel mixture on that cylinder, or a very weak or intermittent spark, often caused by a bad secondary wire or sparkplug boot or even a bad plug.

I’m not sure what jets are in it now. But lets just say I had 135. Would it be safe to put 145 in? I would assume thats the main jet. Would that help balance out the being too rich? I’m gonna be honest, carbs have never been my strong suit.

Thanks!

I just checked, I have a #125 and a #62 in the carbs now. I have a parts carburetor that is the same model as the on I have. It has a #90 and a #65

Do I need the 90 and the 65? Or should I get like a 145 for the main?


Thanks!