TOPIC:

Please excuse me if I posted in the wrong thread, however I'm starting to think my issue is more likely to be related to ignition/timing rather than than a fuel mixture issue.

I won't assume I'm wrong.

Here is where I'm at and what I have done and what I plan to do for my 1979 KZ400 H1 LTD:

Petcock:
Initially the petcock was leaking massively. I have replaced it with a rebuilt one, which still seems to be leaking but I think it's due to the wrong sized gasket that attaches to the tank. I will replace this tonight. The vacuum side is ok.

The carbs have been pulled multiple times and cleaned. I have a rebuild kit coming (which is silly because I really need to up my jets) but it was cheap and it comes with new gaskets. I'm leaking gas on the overflows and will test and adjust the tangs this weekend to fix this problem.

It is possible I have fuel mixture problem and probably do, but I am working out the gas/air side over the next week.

The problem I am most concerned about is the high temp vs. low temp on either exhaust pipes. The right side (looking at the pipes head on from the handle bars, not sure which what the cylinder numbers are) is reading about 300+ degrees within 5 minutes of being started, the right side is lagging at about 120 Deg, and just never gets higher than 180 Deg F. I am using an infrared temp gun, the temps may be off as infrared's don't read well on metal. The point is I am way vs each other.

No matter how the carbs are adjusted the same issue persists. Again, due to the leak and gas issues I have I'm still not positive the issue isn't directly related to this. I will no better in the next week if this is the case.

I'm sure my valves need adjustment as I can hear (using a screw driver to each valve that things are kosher), but the engine compression is between 125-135 psi (can't remember the exact) at both spark plugs heads. They are within 5psi of each other.

I'm going to change out my coil and spark plug wires and suspect this will help. I'm no totally sure if my current coil is bad or not, as I have not tested it. I'm replacing anyway, and will use the coil as a spare if it's ok. I'm also going to put in new points and condenser.

The bike sat out in the rain for nearly two years. Ran fairly well for a long while and is giving me a fit at the moment. I think running it around for two months straight shook it into submission and now it needs some major attention.

I'm looking for further advise on how to troubleshoot this issue. I want to make sure I'm taking the right steps, in the right order. I won't replace the coils and wires until I have the carb/gas worked out first. I'm assuming the lack of work being done on right cylinder section is adding to my lack of power problem (front brakes are dragging and that's part of it) which is did not mention earlier in the post.

Any advice would be appreciated. This is my first bike and I'm hooked, not just on the riding by also vintage bike repair!!

can't add much, since I'm not familar with twins, but the 4's do run similar temp while reading with the same method. I know of one 750/4 that had 3 cylinders the same and one was considerably lower temp, but still not as drastic. Even in that case the bike ran well with no noticable issues, but I thought a carb synch was due.

I don't know much about exhaust temp but I would have to say this isn't an ignition problem. It sounds to me like one cylinder isn't firing all the time. If the coil is firing one side it has to fire the other. It only works if it can ground on both sides. It probably is a good idea to replace the points and condensor but I would hold off on touching the ignition system at all until you have sorted out the carbs. Rebuild them and try running the test again. Also that bike has valves that are really easy to adjust so i suggest trying that too. Another problem could be spark plugs. Try switching them and see if the problem stays or follows. If it stays then thats not it. If it follows then get new plugs. They are NGK B7ES.

I would check the valve clearances as one or more may be partially open affecting exhaust temperature.

Had the exact same problem on my KZ1000. I chased electrical stuff for hours until someone on here suggested the pilot jets. You can't hardly get them clean enough. Pull a wire out of a wire brush and use to clean them. I had to pull the carbs twice before I got it. Then install a inline filter and let the gas flow a couple of cups worth to clean out the lines or you'll be doing this again.