1980 KZ550 Power Issue

I picked up this bike last year and have started working on it recently.
The issue I'm having is that it will run alright at idle with a faint rattling sound in the leftmost cylinder. Maybe it's the timing chain, I don't know.
When I snap the throttle to full from idle without the choke on, the bike will sputter and die. If choke is on, the bike revs up.
When I'm riding it around with mid-range power, it bogs down and has issues till I either drop below an rpm range or give it full throttle (which ends up with me being set back in the seat a bit). It's just not a good scene to relive indefinitely.

It has pod filters (these wouldn't be leaning the bike out would they?), I recently sync'ed the carb's, reset the floats in the carb's, and replaced the vacuum tubing (figured out that was causing my backfiring problem).

Also, I am going to go to the auto store and see about getting some new o-rings for the needle jet and drain plugs in the carb's. (Because of the bad seal in the drain plug screws, the overflow tubes are currently tied off on two of the bowls - does the overflow tube also allow the float chamber to breath?)

I havn't been able to check the timing, or ignition advance mechanism yet, but I'm wondering if the advance is mildly corroded, prohibiting it from advancing until a higher rpm rang is hit... but then again, wouldn't that KEEP me from catching at full upon on the throttle and result in further bogging down?
I also have not checked the valve timing/clearance.

The exhaust has KHI kz550c printed on it so I assume it's the factory exhaust.

Valve clearances, ignition timing and electrical checks for sure....

Carbs... everything you need to know...

kzrider.com/index.php?option=com_docman&...d&gid=461&Itemid=108

OMR

What do the plugs look like?

You have TK22 carbs.
They will need bigger mains for those pods. Stock is 92, you probably want 94, 96, or 98 mains.

Before that though, do what OMR said. Check compression. Check the valve clearances (read the warning in the manual about the cam chain tensioner and valve cover!!!!!). Check the ignition advance. Check for air leaks in the intakes.

There's a manual in my signature if you don't have one.

pusher wrote:

It has pod filters (these wouldn't be leaning the bike out would they

BING BING BING, we have a WINNER!

PODS again...

With pod air filters, your bike will be VERY lean if the carbs have not been re-jetted.

In general, pods require going up about 4 sizes on the mains, 1 on pilots, and raising the needles a notch.

GL!

Sounds good Fellers. I'll press on with the investigation. While I plan on checking all the afore mentioned suggestions, I did have a thought earlier today. If I taped 2/3rds of the pods up with masking tape, would that richen things up enough to do a quick and dirty test to see if it needs to be jetted or not?

To Old Man Rock:

Man the information you shared is awesome. I feel like I just scored on some valuable reading material I wouldn't have read otherwise. Thanks for sharing!

I taped 4/5ths of the pods up with no effect. Tomorrow I'll be tearing into the points and spark advance... maybe the valve timing if time is working on my side.

I didn't get to the bike till today. When I started last week, I realized the previous person had stripped the screw on the cover. I ended up having to buy a backwards tapping bit and back the bolt out. Someone had also stripped the screws on the stator plate, so they must have known something was wrong with the advance.

Ahh.... monkeys they were.

It turns out the pads on the advance are worn down and gone to each arm respectively, one was frozen closed, and the other was a little sticky, and to top it all off, the pivot points that nestle against the shaft bolt were both snapped off.

Does anyone know of any fairly priced spark advances I can buy for the bike, or is ebay my best bet?

I disassembled the spark advance and cleaned it up so the arms moved freely and put it back on the bike. Keep in mind that the anchors against the shaft bolt were broken so it was expanding out further than normal at higher rpm's.
The bike still has the same symptoms. What exactly does the spark advance do?
Also, I have electronic points, not the point breakers.

Your centrifugal spark advance is the timing of ignition relative to the position of the piston....so the higher your RPMS climb the faster your ignition will spark to the piston on the power stroke....

you have to make sure its clean and lubed up...

spray some brake cleaner on your intake boots when its running(between carb and head) if it sputters then you got leaks.....that could cause a lean air to fuel mix. more air then fuel...tighten up pods good and clamps on both sides of boots..precautionary...

its most likely a fuel problem around having to do with your carbs though, these TK 22's are a little touchy....just gotta narrow shit down;)

loud vhx has a manual for some good info...hit it up man.