TOPIC:

Hi All,

I have a 1981 KZ400-J engine and unfortunately the engine has died, and will need to replace it.. I found an 1984 GPZ550 engine without carbs, but I believe the carbs from my KZ400-J engine will fit (hopefully). The problem is jetting. What Jets to use on the TK21 carbs to run a GPZ550 engine? Will be running KZ400 J original 4 -1 exhaust (for now) and some sort of pod filters.

Also, for my information, what is the difference from the TK21 to the TK22 carbs?

Additionally, will the GPZ550 engine need an oil cooler?

Thanking you in advance for your help.

Best Regards

SC

The '84 engine is designed for rubber engine mounts but your '81 has solid mounts. Some adaption is going to be needed.

Regarding the carbs, the later engine is most likely designed for CV type carbs so the rubber carb boots are larger than those for the TK carbs. Pretty sure some adaption will be needed for that as well.

Good luck

As ed said, the later motor will have larger intake holders, so you will have to order new intakes for the older motor and modify them by slotting the mounting holes. The sealing area will be greatly reduced so vacuum leaks will be more likely unless you take great care during carb and boot install. I recommend a progressive install of the carbs and boots at the same time to make sure the boots are not being distorted otherwise vacuum leaks may occur.

Tk21 look to be almost identical to the tk22. The bore is probably a tiny bit smaller and the slide too. But the two carb racks can probably interchange easily.

And yes on the oil cooler. Easy to fabricate a mount if you can weld tabs to the frame.

Check my other links for tk websites.

I have 650 carbs on a 750 engine. I used carb boots for 650, it was bolt on.

Maybe 650 boots can be used for you also?

Good luck!

Thank you all for the comments.

Nessism - I incorrectly stated it was a GPZ550 engine, it turns out to be a KZ550 engine. Hopefully this makes the installation on my KZ400J frame easier.

loudhvx - Any way to correctly identify TK 21 versus TK22 carbs? Inlet size, any particular marks? Just wanted to make sure which ones I got. If I have TK21s (as I assume) any idea in terms of what jets I should put in? The TK22 site has a lot of info, but mainly for TK 22. So Just wondering what the recommendation would be for the TK 21s...

gordone - Will look it up.

Best Regards

SC

scristina wrote: ...loudhvx - Any way to correctly identify TK 21 versus TK22 carbs? Inlet size, any particular marks? Just wanted to make sure which ones I got. If I have TK21s (as I assume) any idea in terms of what jets I should put in? The TK22 site has a lot of info, but mainly for TK 22. So Just wondering what the recommendation would be for the TK 21s...

We never got the Tk21 carbs in the U.S. so I've never seen them in person and the U.S. Kawasaki website does not support parts or parts diagrams for them. Maybe part numbers will show up for Tk21 carbs on other internet parts-seller sites.

I am not aware of any factory stamps that show what carbs they are, but I never really looked very hard since they could only be Tk22 in the U.S. There are some stamps that I never looked at very closely. I don't have a set in front of me so I'm not sure what the stamps say.

The only difference I would suspect would be the size of the throat andmaybe the slide. On my Tk22 website main page there are measurements of the carb's throat. I would expect the Tk21 would have a slightly smaller throat, so if you measure yours and they are smaller, then you probably have Tk21 carbs.

If you take out a slide and measure the diameter, I can do the same to a Tk22 carb and we could compare. But there is a good chance the slides would be the same on all carbs especially since their cutaway number is the same for all iterations of the Tk21 and Tk22 carbs (according to the factory manual).

I'm also changing engines out of my81 kz550 to an 84 zx550 engine. The 81 kz550 uses the tk22 but the second gen engines use cv carbs. The carb boots are different (which I can't figure out what to do) cause I want to keep the tk22 carbs cause I just rebuilt them.
I think yours will also have the tk22 carbs which for the kz550 uses a 92 main jet. You could just buy a dynojet carb kit and it will have everything you need for the 550 engine.

Thanks loudhvx. Will take the measurements this week and will add it here for comparison.

Quigleyje wrote: You could just buy a dynojet carb kit and it will have everything you need for the 550 engine.

Thank you. Will take a look at the dynojet kits.