Z500 aftermarket airfilters

Hi there,

I have a Z500 (1980) with a motad 4-1 exhaust and was wondering whether i could fit aftermarket airfilters to it without upsetting the fueling? K&N or something similar?

Thanks
Ian

No, you will definitely need to rejet.

thanks wired george,
can i just get new jets to suit or would that be a bit of trial and error?

Hey, welcome, that bike looks familiar, I think I followed the auction just to see how much it would sell for, I have a Z500 as well, I'm in Australia though. It took me quite a while to find the stock airbox for my Z500, took ages to find one but I don't really like to mess about with jetting and such and decided to spend my time looking for the airbox instead. I'm also thinking of cafe'ing my Z500, slowly saving up money for that. My Z500 needs alot of work.

Anyway, Its probably going to be a trial and error with aftermarket airfilters, as it always is. I don't think there's a quick solution to that problem, Do you have the manual for it yet? I think someone posted a link somewhere in the forum, if not you can pm me. Good luck with the bike

Since the Z500 is a non-US model, I don't have specs for it's carburetor assembly. Does the bike use mechanical slide Tekei (TK) 22mm carbs? What is the main jet, pilot jet and slide cut out? If you do have Tekei carbs, I seriously doubt you will find larger pilot jets so it becomes a matter up clipping up the jet needles one slot. Slots are numbered 1 to 5 from top to bottom and usually, you will see most carb assemblies clipped to the 3rd slot. If this is the case, clip to the 4th slot to raise the needle. Next, is the main jet. You won't find over-sized Tekei hex headed mains anywhere BUT Keihin mains, although shaped completely different, have the same hole size (in other words a 100 Tekei is the same as a Keihin 100). Go up about three sizes... I can't recall what the step size is for Tekei jets but if you start at a #92.5 you will go up to about a #100 main. Mikuni step sizes are in 2.5 increments. Keihin has jet sizes stepped in 1.0 increments I think and not sure about Tekei but if you have a #98, just try a #108 or something in that range... (these are not real numbers as I have no idea what the OEM jet size is for you bike but are only a guess)... this should allow you to take the bike to redline without running out of gas.

I think the Z500 is a KZ500B model.
According to the FSM your carbs are the TK22P-2A.

Your mains are #90.
Your Idle jet is #32.
Basically it's the same carbs as the 1980 and 1981 550 A, C and D, but with different main jets and different needles. The idle jets and slides are all the same.

With pod filters and the 4-1 exhaust, I would start with #94 to #98 mains. You can drill them yourself with a tiny set of hobby drill bits. It's not really difficult. The number is hundredths of a millimeter. You can convert to inches, if necessary, to get the right drill bits, or you might get metric drill bits (but I haven't seen any metrics that small).
If you are keeping the airbox and just putting in a K&N filter, then I would start with #92 to #94 mains.

Then if your air-screws have to be turned in too far (less than 1/2 turn out) then I would drill the idle screws to #37 (this is the next size bigger in hobby drill sizes). However, don't do this right away. There are many steps in tuning and I found the idle jets rarely need to be bigger. Pods and 4-1 exhaust may need it, but it depends more on the exhaust's restriction. I know a Kerker 4-1 doesn't really need new pilot jets, but a Mac 4-1 can use them.

With pods, if your needle is adjustable, you should probably set the clip to one lower than stock. The stock setting on the adjustable needles is 2 down from top (out of 5). I would go to 3 down from the top. (Don't mess with needle shims, they can cause the needle to bind or rub.)

If you are sticking with the airbox, then the needle change may or may not be necessary.

It's expensive, but Dynojet has a kit for the 550's (kit #2305). It comes with better needles, #98 mains, #102 mains, and #110 mains, for all four carburetors. If you can afford it, and you are using pods, it might be worth it as long as you don't need rebuild kits. But the jets may all be too big so it's a tough call. Really sort of depends on your exhaust.

If you are going to buy rebuild kits (the ones for 1981-1983 KZ550 A, C, D, should work), some of those kits come with new jets and adjustable stock 550 needles. The rebuild kit is K&L #18-2462. It comes with stock 550 needles and #92 mains which you could drill out as needed. Four rebuild kits are a little cheaper than the Dynojet kit.

With all the extra breathing your motor will do, the 550 needles should work ok, but will probably use 2 clips down from the top.

Post edited by: loudhvx, at: 2007/08/24 17:26

WG: here's some info you may want to keep for your files.

The number after the dash in the needle number represents the clip position from the top (out of 5).

The 4D92 needle is the same as the 4D93 needle set at clip position 2 from the top (out of 5).

The USA models have plugs over their air-screw openings, so the air-screw setting is in parenthesis since they are not officially accessible (though, I bet most dealers pulled out the plugs to tune them, because I've never seen a set with plugs). The KZ550D model carbs are also painted black. I'm not sure if any other TK22 (or 21) carbs are black.

This chart represents the models using TK21 or TK22 manual-slide carbs. Later models with CV type carbs are not represented here.

The same bikes, made in subsequent years, using the same carbs most likely have the same internal setups. For example, the 1981 KZ550C2 and 1982 KZ550C3 would have the same setup as the 1980 KZ550C1, because they also use the TK22 carbs. However, the 1983 KZ550A4 uses different carbs than the 1980 KZ550A1, so its setup would have to be different.

Note: All models with TK21 and TK22 carbs have the same pilot jet, slide, and fuel levels.

The West German 550 is puzzling since it is listed as having the carbs from the 400 model, but the 500 uses a bigger carb? Maybe it's a typo in the FSM.



Post edited by: loudhvx, at: 2007/08/24 17:47

wow, thats a lot of info, thanks guys. This really helps me as well. I'm a bit new at fixing up my own bikes, so I'm really clueless about jetting.

does anyone know where i can get these bigger jets from? or will i have to drill the jets out?

Thanks
Iand