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Discussion Starter #1
Hey all,

Bike: Kawasaki Kz 550 1980
Miles, ~27,000
First noticed: 2 weeks ago
Bike issues: non, it runs fine-ish, carbs need cleaning for sure but it runs and starts. I noticed no drop in performance from before and after I noticed this issue.


I noticed a week or so ago, that the outlet encircled in red below appeared to have blown oil out of it. I think this because there was oil caked on the side of the battery and the frame opposite the outlet side (coming toward-ish the perspective of the camera). The shiny reflection you see in the battery housing is oily. There also used to be some sort of cloth plug in the outlet that is no longer there. All this leads me to believe oil popped out of there. I did overfill the bike a bit so this could make sense but I do not even know what this thing does or what it is so it is tough to say for certain.

For reference on where this is in the bike, just aft of the battery housing, below the carburetor air intakes, sitting atop the engine.

I looked through the Clymer manual (covering mostly the section regarding engine) and could not find any information as to what this is. Does anyone have any idea of what it is or where I should focus to find information on it? Thanks!

ps. here is a video of my phone exploring around the areas for better orientation


41397
 

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I don't know what the rectangular part is, but below that is the crankcase breather cover (round/silver). When the engine is over-filled, excess oil will get expelled thru the breather. It should not be plugged with a rag or anything. Stock, there should be a breather tube connected to the airbox so that crankcase fumes can get burned when the engine is running.

With individual pod filters, you should install tubing on the breather to keep water out of the engine. route the tubing behind the engine, forward of the swing arm. Warning: oil could get directed towards the rear wheel, so try to route the tubing to the left or right, but away from the drive chain & mufflers. I would install the stock airbox.

Engine oil. Warm up the engine, then turn it off. put the motorcycle on the center stand & let it sit for a couple of minutes, then check the oil level at the oil gauge sight glass. The oil should be between the two lines. If the oil is low, add enough to raise it to the proper level. If there's too much oil, remove the excess by siphoning thru the oil filler.
 

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Thank you all for your responses. After popping around the internet a bit, it seems I have a choice. To figure out if the carb has been rejetted (and rejet if not) or to find a air box and re-install it. Unfortunately, I do not have the airbox. If I did, I would likely go that route.

I understand the coolness of the pods and their supposed boost to performance, but I fall in the camp that the original engineers knew what they were doing and did what they did for a reason. So I am going to compile some information and search for the part. Thank you all for your information. This is has been super helpful
 

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loudhvx over at KZ-Rider has a ton of info about the 550 & the TK22 carburetors.

The pods filters might give more power at certain rpms, but not others. The stock airbox provides a stable air intake environment, so the motorcycle's performance is good over a wider range of rpms.

Stock airbox. New airbox ducts are still available for the 550A/C models & maybe the stock air filter. check Partzilla & Z1Enterprises dot com. You might be able to find a good airbox on EB >> I would only get one that has the cap >> the cap is typically hard to find on some models.
 

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Hello, I realize I am late to the party, but wanted to share my experiences in rebuilding my 1981 KZ550C. I have had the entire bike apart except the engine itself. I have a whole laundry list of things I've done to this bike. Both major and minor. First off, if you need a stock airbox, I have one that I would be glad to sell you. I actually have 2 but I am keeping one in case I ever want to put it back on. In general, I agree with folks who say that it's best to leave the stock airbox on as well as all the other garb that came with the bike. These engineers were professionals who designed the bike to function optimally. However, almost 40 years later, I have had a very different experience. To make a long story short, I was having problems with low power, poor starting, hot pipes, and an overall sluggish performance. During this time I became increasingly tired of pulling the airbox on and off. The airhoses were stiff and I seemed to damage them a little more each time. So I decided to switch to pods just to make it easier on myself and also rebuilt the carbs with raised needles(1 notch to adjust for the increase in air). I also scrapped the secondary emissions system(the network of hoses that connect to the cam housings, carbs, and airbox. This was the engineers attempt at meeting emissions requirements, it's not something that was designed to enhance performance. Gases that arent burnt 100% are re-routed and burnt a 2nd time before being evacuated through the exhaust. Honestly , I couldnt be happier with the results! Switching to pods and rebuilding the carbs made it a new bike. I dealt with a whole crap-load of other maladies including a seized timing advancer, a fried IC igniter, electrical leaks & shorts, and more. But nothing breathed new life into this old bike better than letting it breathe. Most of all , I have learned that these are finely tuned machines. If I turn the airscrews so much as 1/8 turn, it runs differently. Not having an airfilter on while trying to work on it is doing yourself a disservice because it will run very differently with a stock airbox vs pods vs nothing. It's not possible to tune it to run efficiently across all 3 scenarios. It's best to work backwards with performance issues. Put the airbox or pods on and then try to get it to run right. After doing all of that, I upgraded the exhaust. I chopped off the stock mufflers and welded new ones on. It changed the sound considerably. Even though it wasn't my intention, it sounds almost like a harley(almost!). That cooled the pipes down a lot! Maybe the old ones were plugged or something. But again, after that I had to re-sync the carbs and adjust the airscrews after doing this. My airscrews are almost all the way closed now, so I think I need to raise the needles one more notch in order to compensate for the increased flow in the exhaust system. This bike is now a daily rider. I bought it for $375 in April 2018. I have put about $1000 into it after purchase($350 was new tires). And as I'm sure you know, the crankcase breather is important. Serious damage can result from keeping that plugged. Pressure will build up. Almost every other port can be plugged. Full disclosure: this was my first bike purchase. I am not an expert at all, but I certainly learned a lot about this particular make/model. Countless hours spent examining parts, cleaning things, and testing electricals. It helps to have a carb sync kit($50 on ebay). I must've synced the carbs 8-10 times now. Other than that....carbs carbs CARBS. Those freaking things will stop functioning correctly if you look at them cockeyed! They need to be clean with new parts, and then kept clean. Sorry for rambling on. If I can help at all let me know. And let me know if you want that airbox. [email protected]
 

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Thanks for the reply. I actually read it: the whole thing. hee. In regards to the individual pod filters most 550s have TK22 mechanical slide carburetors which are easier to tune for pod filters than CV carbs (found on the 550 GPz models). As mentioned above, loudhvx has a ton of info about TK22 carbs & I think he has jetting info for pod filters.

If the airbox ducts are hard, it's best to get new ones, but sometimes not an option, depending upon the model. My airbox ducts are soft, so no worries there. You probably realize this now, but instead of having to pull the carburetors off the motorcycle a million times, it's best to do the complete disassembly & cleaning (and clean the fuel tank & install an in-line fuel filter if necessary). I removed the carb bodies from the rack & soaked them overnight in the good Berryman's carb cleaner dip >> in my case I don't think it was necessary, but that's what I did. The brass parts were fine, but I replaced the gaskets and all of the o-rings & rubber bits. With the soft ducts & full cleaning, I only had to pull the carburetors off once. :)
 

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Thanks for the reply. I actually read it: the whole thing. hee. In regards to the individual pod filters most 550s have TK22 mechanical slide carburetors which are easier to tune for pod filters than CV carbs (found on the 550 GPz models). As mentioned above, loudhvx has a ton of info about TK22 carbs & I think he has jetting info for pod filters.

If the airbox ducts are hard, it's best to get new ones, but sometimes not an option, depending upon the model. My airbox ducts are soft, so no worries there. You probably realize this now, but instead of having to pull the carburetors off the motorcycle a million times, it's best to do the complete disassembly & cleaning (and clean the fuel tank & install an in-line fuel filter if necessary). I removed the carb bodies from the rack & soaked them overnight in the good Berryman's carb cleaner dip >> in my case I don't think it was necessary, but that's what I did. The brass parts were fine, but I replaced the gaskets and all of the o-rings & rubber bits. With the soft ducts & full cleaning, I only had to pull the carburetors off once. :)
Thanks for reading it all:) Believe it or not I actually skipped a lot of my rebuild story. At first, I didn't rebuild the carbs, I just took the whole bank off, removed carb bowls, removed the pilots, and let it soak for a few days. This helped a little, but I definitely got the feeling that it was in need of new parts. The original needles were a little worn and the gaskets were brittle. Most of the little o-rings were trashed or missing. As for the airbox ducts, I actually did replace them with new ones at first. They hardened up again after only a few rides around town. The engine was getting really hot! The headers were very blue. So then I rebuilt the carbs with new kits and synced them. It made a huge difference, but RPMs were flatlining around 4000. Timing advancer was stuck in one position. This made me question everything I had done up to this point. Then I started thinking about the exhaust and inspecting the emissions system. By now, I had had enough of that dang airbox lol! I switched to pods, pulled the carbs once again to raise needles, re-synced, and adjusted airscrews. It's true, I ended up pulling carbs and syncing them more times than I needed thanks to other things that I wasn't aware of at first, but hey I know those carbs backwards and forwards now! Changing the exhaust really helped a lot too. Runs cooler and the pipes aren't blue anymore. My next tasks include, replacing the choke flaps in the carbs(I'm missing 2 and didn't realize how important this is to starting as it throws off the vacuum), re-building the advancer, and rebuilding the rear brake drum. After that, there's not much left for me to do except polish it up. I've done mostly everything else except rebuild the engine itself which I don't feel qualified for. I will probably take it to Portland in the near future to have the valves checked and adjusted, but it doesn't even have a single hiccup or backfire and it has a lot of power. I am thinking of making a riding video to put on youtube. I will post it here when I do. Cheers and thanks! I will check out the TK22 info.
 
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