KZ650 #1 exhaust header glowing red hot

I finally got my bike running after days of cleaning the carbs and charging the battery, which i suspect was the real culprit. Anyways I have not yet synced the carbs, but I have a 4 into 1 exhaust and at first they were all glowing red hot until I adjusted the idle and now only my #1 header is glowing red hot. there is a knocking sound coming from that side of the engine also. Could this be do to the carbs being still dirty or out of sync? I let it run for about 5-10 minutes but got nervous I would hurt something so I shut her down. The bike has electronic Ignition if that helps. thanks in advance guys, you all help so much. Much appreciated!

Sounds like it's running very lean or your timing may be too advanced. Are you using the stock airbox & filter? Be sure to use a powerful fan to cool it if you let it idle; air cooled engines don't like to sit running for extended periods. Ed

Ed, Im not sure if this bike came stock with pods, but that's what is on the bike atm. Next time I will definitely stick a fan infront, thanks for the headsup. I'll try adjusting the air screw on the carb in a few 1/8ths of a turn to see if that relieves the problem.

No KZ ever came stock with pods. So the question is what did the previous owner do when he installed them. Did he rejet,, and if so, did he get it right? You may want to examine the carbs to see what jets/needles are in there and get advice from folks on this site as to what they should be for pods. Ed

If not already done, would assure that the timing advancer is operating properly, and not sticking in the retarded idle position.

The weighted arm pivot points may require lubing, or the entire unit may need to be removed, cleaned, inspected, and lubed.

Shouldn't look like this:





Good Fortune!

Looks like I'll take the carbs off once more and check to make sure I have all the correct jets in there. wouldn't hurt to clean them once more I suppose. I'll try checking on that timing advancer as well. thanks for all the help!

the first thing I would do is find a can of spray seafoam and pull the spark plugs(expecially the problematic cylinder)- then clean off the cylinders. beware, a good idea would be to do this pre or mid oil change so it runs out the drain plug once it gets past the rings.

For a KZ650 w VM24 carbs w 4-1 exhaust system & pod filters:
Ballpark: #115 main jets, #17.5 pilot jets, jet needles clipped or shimmed (the 81 CSR needles have no extra grooves for raising them by moving the clip, so you'll have to use small washers as shims. I'd probably use ss).

You should only have to clean the carbs once - do it thoroughly. Drain & clean the fuel tank & inspect for rust. Install new fuel line & an in-line fuel filter, especially if there's rust. Larger rust particles can clog the petcock screen. Some of the rust gets pulverized from vibration to a fine enough size to pass thru the screen.
Make sure the petcock is functioning properly.

Air mixture screws (pilot adjusting screws). I guess a good starting point would be 1.5-2 turns out. not sure.

Do the service fuel level check. The fuel level in each carb should be 3 mm below the bottom of the carb body (+/- 1 mm, but I set mine spot on at 3 mm).

Check the accelerator pump. Supply the carbs w fuel, prime the pump circuit by actuating the throttle pulley a number of times, then actuate the pulley vigorously: fuel should squirt out the nozzles straight back without hitting the carb bore walls. If it dribbles out or is crooked, the nozzles may be clogged.

Do the initial mechanical synchronization. One way is by using 2 to 4 drill bits (send a pm if you'd like the procedure).

Do the carburetor synchronization. Use a fan to keep the engine from overheating.
Either go ahead & get a vacuum sync set or make one. Homemade: 1/4" watering system fittings from the HomeDepot - 2 tees & 2 90^o s. 1/4" clear tubing ~4x10'. Attach it to a 1x4 board. simple. Use 2-cycle engine oil as the fluid. The homemade jobbie may not be perfect, but it will get you close. Or go ahead & get the proper tool.

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Martin, you are incorrect on the your statement. The VM24 carbs do have adjustable needles, 5 slots for the clip. I would put the clip in the middle slot to start with.

My 650 has a 720cc big bore kit, some minor porting, RC 4 into 1 pipe, pod filters running the VM24 carbs. My specs are
Main jets Dynojet #118 that is about equal to the Mikuni 115, 17.5 pilot jets, Needle clip in the fourth one from top, idle mixture screws 1 1/2 turns out. Runs fast, smooth, starts easy and idles smooth.
Do not let the bike idle that long without some means of cooling it. As mentioned before these things are air cooled. It does sound like you may still have dirty carbs. On older bikes that have sat for a while I always end up having to clean them more than once. Does the bike run past idle and does it run OK?