You should consider a number of things before proceeding. I'll use my Z1-900 as an example. Years ago I upgraded the stock spoked wire wheels to DID alloy rims and SS spokes/nipples, a 2.15" x 19" front and a 3.00" X 18" rear on the reinforced but stock swingarm. Handling improved as I changed the front fork damper rods to later model KZ900's along with Progressive front springs and Progressive rear shocks. So the stock geometry was not significantly changed from stock if at all by the changes. I braced the frame a long time ago by the way.

In 2006, I replaced the DID alloy wheels with wider 17" Excel alloy wheels wide enough (3.5" and 4.25") to support the use of radial tires, and added a GS1100 swingarm and a rear disc brake setup. Here I had to consider how this bike's geometry and total height/ground clearance would change along with its handling because of the 17" wheels. I even took into account the actual diameter and width of the Avon AV45 and AV46 tires I wanted to use, the resultant trail changes, wheelbase change (the GS1100 swingarm is longer than the OEM Z1 swingarm) etc. I missed one important item that surfaced with use of 17" wheels and OEM KZ1000 front and rear calipers: I will spare you the details for the moment.

can any of you point me to the right direction for info on doing this swap? have a 79 Kz 750. would like to stretch the swing arm some and really would like to find a way to go with front and rear disk on it

Thanks Leon

I'll have it up on a jack as soon as my new rubber shows up and will check the front and rear ends thouroghly, I had a feeling the steering bearings might need attention, under takeoff I thought I could feel a bit of play. Tapered roller bearings were on the horizon anyway, the bike has a front end and rear swingarm swap in its future.

if you can get the bike up off the ground you can grab the front wheel and pull it back and forth and feel for slack in the steearing bearings.
myself personally,i ride the bike and squeeze the front brake and watch the steering stem nut for movement relative to the fuel tank,if you see front to back movement the bearings are loose.
chances are they have set long enough to condense some water in there and have pitted the races and you are feeling the balls roll down into the pits and up out which will try and hold it in the pits and then bounce em out.so they are effectively acting like detent balls.
if you turn it side to side while off the ground feel for notchiness as well.

same deal on the swingarm remove the shocks and try to move it side to side and watch where it connects to the frame and watch for movement that will indicate worn bushings/bearings.

changing fork oil would be prudent.i wouldn't worry about checking brake disk runout unless i did not find anything else that could cause the wobbling.

hth,
leon

So I've been doing some short rides on the 78 kz1000 I've got running, test rides close to home if you will. Too see what other things need attention after sitting for 17 years. I noticed a front end wobble at low speed when I let go of the bars, when I get it up to speed and let go of the bars it doesn't wobble. I'm guessing steering bearings are my first thing to look at, I have new tires coming within the week. While I'm at it I should drain and add fresh fork oil, check front rotor for trueness, rear swingarm bushing for wear and I'll check the wheel bearings once the wheels come off for new tires.

Anything else I should look into in regards to steering wobble?

Other things I've learned from my shakedown rides, new side cover bushings are in order. In 5 gear between 3/4 and WOT the side covers fly off, haha. The clutch feels like it slips till the bike warms up, was expecting some clutch issues with it sitting for so long. Float needles seem to be leaking when the bike is off, I shut the petcock off and noticed the clear fuel lines were empty after a day or two. Will change the oil again and check for gas in it and see if that helps the clutch slipping problem. Once it warms it doesn't slip, even under hard exceleration.

Man what a fun bike to ride, it sure has some guts for an old bike!

BohicaBob runs a 160 seach bohicabob it look sick with the 160

My novice understanding is that you will need a 4.25 - 4.5 inch rim for 160 tyre. You will probably need a 530 chain and spacers also

Hello Jason, thanks for the info. I'm still waiting to find some GOOD goldwing shocks for a GOOD price, anyone.....?


And as far as tire size? I WANTED to go 160, but I keep seeing so many different answers to this question??? I know it had some to do with rim size as well. I'm running a 18" rear wheel, but it's wider than stock, by how much, I don't know?? But I think I'm going with the Avon Roadriders. 150 out back, and 90-90-19 up front.



If anyone else out there can answer this tire thing for sure, would help.

Gday

I am in the process of doing the same thing to my kz900 just gathering parts converting over to rear disk so getting that stuff

read this thread pg3 a good hint on wheel spacers

www.ksrc-au.com/phpBB3/viewtopic.php?f=3...f605292d0c9&start=30

also search BohicaBob he has been really helpful under his signature he has a link to z900 stage two with heaps of pictures.

post some pics as you will be ahead of me on this one. BTW what tyre are you going to run? im thinking 160

cheers Jason

Just got my GS1100 swingarm, time to get her up on the table now! And the guy threw in some pretty nice Magura levers he had laying around as well. Lots of plans and little money, but will keep posted what I do to my old school. Anybody got any good useful tips on this swap I'm listening. Later kzr members.

Intro, I'm new to this forum, I owned my Z1R since I first bought it Dec 1977 in Melbourne Australia. So far it has covered just on 200,000 kms. Many bikes came and went but the old Z is still here and still puts a smile on my face everytime I ride it.
Currently - Engine -1080 MTC pistons, J model valves, mild speedway cams, ZRX1200 carbies (the best mod I had). Dyna coils and ignition, Dyna rev limiter (crank not welded therefore limited to 10,500rpm), heavier valve springs.
Frame- modified the usual places, front discs/ calipers are from 2006 R6/R1, hydraulics are GPZ (zx) 1100, clutch is also hydraulic with GPZ900R actuator.
Rear end has GPZ750 turbo swingarm modified to suit with a GPZ900R wheel/ brake (saved 25Kg in weight)
Exhaust - Marving racing, without duobt the best pipe I have ever tried and I tried many
The bottom end/ gears are still original, apart from the shaft seals.

The bike now handles brilliantly (for an old bike), brakes better, The engine goes like the clappers, it beats my other work horse a modified FJ1200 in both topend torque and power and still delivers better economy.
Thanks for listening, I hope I can contribute to your forum