KZ550 F2 Shaft - jets for pod filters and 4-1 exhaust

Been doing a soft rebuild of an 84 KZ550 I got last autumn. It ran pretty poorly before I put it away for winter and I want to do everything I can, short of pulling the engine. It already has pod filters and a 4-1 exhaust, but how poorly it was running makes me think it has stock jets (based off what I've read, I have minimal experience with carbureted engines).

I'm already looking at brand new pod filters just for safety, but I want to know exactly what pilot and main jets I should be looking for with this bike in this setup. The only kit I can find at a reasonable price is the dynojet kit for the the GPZ550, but I can't find difinitively whether the two models use the same carbs. Am I safe to go with that kit? Should I just drill out the jets instead, and if so what sized bit should I use? Any advice would be appreciated.

Your bike and your choice - but if possible you're probably better off sourcing an airbox if you can. Half the topics on bike forums are from people trying to fix their bike's poor running after changing to pods. Even if you can get it jetted properly (which can unfortunately mean a lot of trial-and-error unless you can find someone who has put the same brand pods on a similar engine), pods aren't consistent - weather affects them greatly, and even a cross-wind can make the cylinders on one side of your bike lean and the cylinders on the other side rich. They do look nice though.

If it runs poorly at part throttle and low revs, that means your pilot jets or pilot screw adjustment needs attention. If it runs poorly at full throttle and high revs that indicates your main jets need attention. The easiest way to see what you need is really to take the carbs off and check the jets, the size should be stamped on them. It may well have been jetted correctly in the past and is now just clogged from sitting - you won't know until you take them off. If the bike has seen much fuel with ethanol and has sat for a long time it's pretty common for the carbs to just gum up. A clean might be all they need.

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Your bike and your choice - but if possible you're probably better off sourcing an airbox if you can. Half the topics on bike forums are from people trying to fix their bike's poor running after changing to pods. Even if you can get it jetted properly (which can unfortunately mean a lot of trial-and-error unless you can find someone who has put the same brand pods on a similar engine), pods aren't consistent - weather affects them greatly, and even a cross-wind can make the cylinders on one side of your bike lean and the cylinders on the other side rich.

 

Amen!  He is absolutely correct!  Ed

wrote:

wrote:

Your bike and your choice - but if possible you're probably better off sourcing an airbox if you can. Half the topics on bike forums are from people trying to fix their bike's poor running after changing to pods. Even if you can get it jetted properly (which can unfortunately mean a lot of trial-and-error unless you can find someone who has put the same brand pods on a similar engine), pods aren't consistent - weather affects them greatly, and even a cross-wind can make the cylinders on one side of your bike lean and the cylinders on the other side rich.


 

Amen!  He is absolutely correct!  Ed

I concur, fully!

 

If you can't find an airbox, maybe try installing homemade extenders between the carburetors & individual pod filters. use good filters.  I think the extenders help to cut down on air turbulence.  Also, you probably should make a carburetor support bracket so that the carbs don't bounce around >> to protect the carb holders at the cylinder head.

ps: loudhvx has a motorcycle stuff page w lots of info for the KZ550. see links in his signature. not sure if he has a carb page for 550 CVs.

If you want to pick up an airbox,  here  is one that will fit, and it's not that expensive; if those boots are hardened, it's about another hundred for four new OEM (14073-1083). 

That being said, if you don't want to go that direction, I would try going up two sizes on your main jet and one on your pilot. I'm afraid I don't know what type of carbs you use, other than your stock numbers are 120 main and 32 pilot, so not sure where to get them. 

This one looks similar to the one Ghostdive posted.  Mabye?

ebay.com/itm/234461411914

If you want to pick up an airbox,  here  is one that will fit, and it's not that expensive; if those boots are hardened, it's about another hundred for four new OEM (14073-1083).   That being said, if you don't want to go that direction, I would try going up two sizes on your main jet and one on your pilot. I'm afraid I don't know what type of carbs you use, other than your stock numbers are 120 main and 32 pilot, so not sure where to get them. 

I actually just managed to snag a full airbox at a good price. I saw the one you linked but unfortunately that seller doesnt ship to Canada.

Thank you for the info about jets though, at some point I would like to do some engine upgrades and eek a bit more performance out of it, so this is very helpful.