81 kz550 performance, what can i do?

I am working on an 81 KZ550 shaft drive, and would like to upgrade performance, but so far I can't find anything about what can be done to this bike/engine. ANY advice/tips or links would be appreciated!

Well, you can do the same as to any other engine. How much extra performance are you looking for? If you aren't doing it for the experience or fun, it would be cheaper to buy a bigger bike though.

TheForumTroll wrote: Well, you can do the same as to any other engine. How much extra performance are you looking for? If you aren't doing it for the experience or fun, it would be cheaper to buy a bigger bike though.

+1 How much money are you willing to spend for increased performance, and will that amount buy more performance by just getting a bigger bike or by trying to modify the KZ550? Ed

kawasakimotorcycle.org --- Boring out a KZ550...

motorcyclistonline.com --- Kawasaki KZ550 LTD | MOMBA Bike Build

A bigger bike is probably in the works this winter, but the riding season in WA is pretty short, and I personally think riding in the rain is a pain in the a**, so I'd like to get it as nice as I can, as fast as I can.

Ive been making a list of changes I think I should make now, and so far that is:

Build custom bare bones wiring harness
swap bars for drag bars (the bike came with a really nice set of Z-bars, but they are 1". If anyone is interested in them let me know)
clutch control handle
solo springer seat
do it yourself hardtail kit
peanut tank (or any high sitting tank)
stage 3 carb kit
forward controls

That doesnt look like too much of a project does it? Other than the wiring harness kit, clutch cable, and carb pods I dont have any of the above parts listed. If anyone has anything that would work that they are willing to part with please let me know. I am trying to get in the wind as quick and cheap as possible.

You can add a certain amount of power to it, but no matter what you do to it you won't be hunting down 1200 Bandiits for dragraces.

If your engine is tired, you can have it bored from 58mm to 61mm, install the Wiseco high compression pistons, and then buy a '81 GPz550 head & cams to put on it, put in some Canadian Jet Needles and bump the main jets up a step, and you'll be about 10hp richer, and about $2000 poorer if you have a shop do the engine work.

The bang for the buck really isn't there on this one. Do a build to a 1100 and you have a monster.

Looks like a fun little bike, and I'd recommend those jet needles and a set of #94 main jets, just to help with the cold-bloodedness.

Nice project, bikes like that 550 are great for bobber/chopper projects.

Engine wise you do anything your wallet can handle. Best gains will come from the head, the GPZ engine had a better head design and more aggressive cams. You can ship your factory cams to places like Web Cams or Megacycle and have them hard welded and re-ground with high performance profiles, that will wake the motor up. Wiesco pistons are available. The shaft drive is what it is, not much to be done there.

Your bike is an 81 and should have a factory electronic ignition ( that's a good thing) and it looks like someone put BS carburetors on it ( another good thing).

As others have said, if you want to go fast on the cheap, this is not the bike to do it with. That doesn't mean it can't be done.

I don't think your bike is an 81. You have the later style motor with shaft drive.
That style motor did not come out until the 82 model year with the second Gpz550.
The F model Spectre came out in 1983.
It came stock with TK-26CV carbs which look like what you have.

You can put a 615 kit in, and use the pistons from a Gpz to get more compression and top end from a Gpz to breathe more, add a Megacycle cam and some CV30 carbs from a ZR550, but I don't know if the shaft hardware can handle the extra power. You will definitely have to add an oil cooler if you do all of that.

And there will be nothing cheap or fast about doing all that. The tuning alone will likely take several Dyno sessions, which translates to months of on the road testing.

I think you will have your hands full just tuning the stock carbs for pods. You will want to look into a Dynojet kit for 82/83 Gpz550 (Kz550H1/H2), I think it's kit #2107.

I thought factory carbs would be the TK-22's... The 550 I had was that way anyhow.

Here is a pic of an 82 with the mechanical carbs just like the one I had. Curious when they made the switch.

Yes, that is the older style motor with mechanical slide carbs (Tk-22). Notice the corners and edges are more rounded, and "classic" looking.

The newer style motors had more simple, hard edges. All of the newer style motors had larger intake ports with CV carbs. The shaft drive only came on the newer style motors.

Ok, after doing a little research online it turns out the bike is an 83 Spectre!
Thanks for the info!