Bike won't idle - suspected carb issue

It's a 1983 Kawasaki GT550 (UK-only model), also known as the Z550 G1, registered in 1984. Info duly added to sig. I don't have the owner's manual for this bike - just the Haynes, which covers a massive number of different bikes, engines and configurations. The Aussie owners manual for the GT550 says it uses Keihins. However, mine has TK26s (make and model clearly stamped onto the carbs themselves).

Would be grateful if you could advise whether these need the plugs.

Ok, sorry. I didn't realize the bike is a non-US model.
I don't have much info on the Gt550 since we did not get them here (USA)... shame as I would have liked to tinker with one.

I can't seem to find any definitive photos showing which TK26, if any, came stock on the Gt550. It's also possible someone installed some TK26 carbs from another KZ.

But there are several ways to tell if you need the intermediate jet and the pilot plug.

1) Scroll down on this page: s3.amazonaws.com/gpzweb/TK26mainPage/TK2...TK26portRouting.html
It shows the port routing of the Tk26. Scroll about half way down. Look for a small passage marked with a "6" on the images. That passage feeds fuel from the intermediate gallery to the pilot. If the passage exists, there will also be a brass plug shown in the next photo and marked "plug". If your carbs don't have the plug and passage, then they don't use an intermediate jet and don't use a pilot plug.

2) Another thing to look for are the threads for the intermediate jet. Look on the main page of the TK26 site. See the intermediate jet. The port that it screws into will have threads very visible. If there are no threads, then the carbs don't use the intermediate jet or the pilot plug.

3) If the carbs don't use the intermediate jet, the main jet will have a larger orifice and thus will be stamped with a larger number. So if the main jet is less than 100, like somewhere near 86, then it probably uses the intermediate system and pilot plug. If the main jet is greater than 100, like 110 to 120, then the carbs probably don't use the intermediate system and pilot plug.

Hi,

A good way to find parts diagrams for specific Euro models is via the website CMSNL. www.cmsnl.com They are in the Netherlands and have full year-by-year parts diagrams.
They also stock a lot of the old parts.
Is this one any good to show what plugs should or shouldn't be there?:
images.cmsnl.com/img/partslists/kawasaki...ae0008e1612_cd4a.gif

Regards,
Rupert

NAILED IT!

At least, I think I have... Thanks to a whole day of working on the bike, it's finally idling without choke, it's sharp and responsive to the throttle, etc. It has a steady idle even though it's not properly balanced with a manometer. Throttle return spring needs cleaning, but the major headache is, hopefully, out of the way. The airbox is a major pain on this bike btw. Seems determined to strike a fiendish deal every time it comes off or goes back on: "either I will squish the rubbers out of shape or you're not getting the carbs on!" I figured out a way to make it work though. Involves removing a lot of bolts and separating out the air box into two. Still isn't an easy task - was very tempted to chuck it out and fit Ebay pods, but I know it will throw out the running. Wasn't made any easier by trying to force the carbs bank into the ancient, hardened intake rubbers.

Thank you very much for the useful information. I examined the diagrams thoroughly, and am 100% confident that no secondary plug is required on my carbs.
They appear to be a version of TK26 that has a deeply recessed pilot jet, so there's no need to stop it sipping fuel from the carb bowl. That website was really useful in explaining how this carb works btw.

While I'm happy for now, as the remaining tasks look less challenging than this one (replacing the leaky cam cover gasket, sorting the brakes out, etc.) I find it strange that this bike needs to warm up for so long before it will idle. I have another carb'd 4-cylinder air-cooled bike and it idles steadily after just holding the throttle open a fraction after starting. However, that one may be running a little rich on the mixtures.

Speaking of mixtures, the Haynes manual states very clearly that this model of bike requires the mixture screws 2 turns out. However, all of them were 2.5 turns out, when I got the bike. I put them back to 2 turns out, but perhaps the guy who rode this thing used to have them 2.5 turns out because it always took a bit of time and choke before it would idle. Certainly far from a sorted bike, but now I can get on with other jobs on it.

Thanks again guys.

Nice job. I'm glad it's running.

Before you remove the valve cover, please read the valve train warning link in my signature. Installing the cover improperly can damage the motor.

Thanks for the heads-up. Do you know any easy way to reset the CCT? For example, on my Yamaha I remove the CCT's spring, then the CCT, then retract the CCT all the way in, before reinstalling the CCT, then reinserting the spring, then very slowly turning the engine over at the engine by hand, letting the CCT click into place. Is that feasible on these bikes?
BTW, the warning you published regarding the CCT and valve cover reinstallation is pretty alarming, so I checked my Haynes, but there was nothing in there. Seems a bit tricky simply putting the valve cover back on, tbh. I would prefer to be able to see that the marks line up when the cyl 1 is at TDC on compression.

yes, I went a little overboard with the warning as an inside joke with some guys on the Gpz550 forum. No one was really paying attention to it and just skipping forward to the camshaft duration info etc.

Some of the manuals have warnings, but not necessarily with the text regarding the valve cover installation. The warnings are in there, but yes, they are hard to find sometimes.

If you look in my signature, that other link goes to another page with links to several Kz/Zx/Zr 550 manuals. They may be of some use to you, and they're free. Also, you can follow the cam page back to the home page (or follow the links in my signature) to get to other Kz550 related info. I'm not sure exactly how much relates to the Gt 550, though. For instance, the early Kz's have a clutch adjuster on the left side of the bike. The instructions for that are vague in the manuals since there were two types used there. I have a link to a graphic on how to adjust the newer type properly. But even newer Kz/Zx 550's use a clutch adjuster on the right side. I'm not familiar with that type. So depending on if your bike is different or not, some of those pages might be helpful.

On the Kz/Zx motors, it's very easy to release tension on the CCT. You just unscrew the big 17mm cap on the crosswedge assembly underneath the carbs. Then pull the spring and crosswedge (they sometimes just pop out, so be aware). That will allow the tensioner to retract while still applying tension (normally it applies tension, but will not retract).
The crosswedge usually goes back in pretty easily, but if the main plunger has rotated, the crosswedge might not want to go in fully. You have to wiggle it back in and then throw in the spring and squeeze the cap back on. If it's very difficult, that usually means the crosswedge is binding a bit and needs to wiggle in farther.

The later part of the camshaft page has graphics on cam timing. You can visually see the exhaust timing position with the cover off, but you won't be able to see the exact intake timing position. But there is not really an adjustment. You simply count chain pins. If you inspect the cam chain guides, and they look good, including the one in the valve cover, then the timing will be more than adequate for a normal street bike. Racing motors may benefit from more precision, and some people take an old valve cover and cut windows in them to see the marks. You can also simulate the chain droop between cams to get an idea of how close the intake cam is.