TOPIC:

A few questions for those of you who have trashed your stock KZ swingarm and replaced it with something else.

What did you replace your stock swingarm with?

Was it new, or used?

What was the cost of the replacement swingarm?

What was the cost of the complete conversion?

What was your reason for the replacement?
1. Improved handling
2. Improved looks
3. Both

If your reason was for function, did it in fact improve handling?
1. Yes
2. No
3. Not sure

If your reason was for looks, were you satisfied with the results?
1. Yes
2. No
3. Not sure

Was the effort put into the conversion worth the outcome?
1. Yes
2. No
3. Not sure

Last question.

Was the cost of the conversion worth the outcome?
1. Yes
2. No
3. Not sure

The reason I ask these questions is I thought about replacing the stock swingarm when I do my 650 cafe rebuild. My reasons were twofold. First, for looks. Second, for better handling. Then I thought back to all the articles about how good the KZ650 handled. So, I asked myself, why mess with a good thing and chance going in the wrong direction. Would adding a couple of inches with, say a GS1100 swing arm actually help the handling? Correct me if I'm wrong, but wouldn't the shorter stock swingarm be better for tighter cornering? Would there really be any noticeable difference worth the time and expense? Or, would it be more worthwhile to spend the money elsewhere? I look forward to hearing your opinions and if you have done a swingarm swap, pictures would be great. Thanks!

Whatever you do you need to at least change out the bearings. The front steering bearings would love an update to a set of timpkin (sp?) tapered bearings and the swingarm pivot bearings and shocks should be replaced for better units. That alone will give you much improved handling. As far as extended swingarm on a 650 unless I am way off here that was added to the big power bikes to keep the front wheel down and for looks for those who like the drag racer look. Personally, I don't like the feel of a limo when I drive and to me I rode my friends z1 and I guarantee you this: the handling is NOT improved. He says this and he says that, I say he is full of shit. Whatever, to each their own. I doubt you really need to worry about that but it's just my two cents. Some guys only like the look of a stretched wheel. I am with you on this matter, sure it looks cool but if it hinders the handling why do it?
I think if you do a stock unit I would consider a nice stiffer swinger that is stock but no more than two inch stretch. I rode a bike with a 6 inch stretch and it felt like it took forever to corner, on the city streets it looks cool in reality it's just not useful at all unless you are at the track ripping shit up.
One last thing, if you wanted a bigger rear tire, if you wanted some nice wheels that are wider in back then you will need a swingarm. Depends on what you will do with your bike. When you start the mods so goes the money with a quickness. I have too much already in to my bike that I could have bought a zx14, I think I would rather have kept her stock and just prettied her up and left it at that. After all at the end of the day it will still be a 650 whereas if you spend that money you could easily buy a nice zrx1200r and make your bike look nice and original with a flair for a few nice improvements.

saxjonz:

My plans at this point are keeping the stock tank, but going with a factory looking Kawasaki 750 RR tail and seat, along with a RR type of fender. I'm going to strip it to the frame and paint everything. I figured that would be the time to do the swingarm modification if I was going to do it. But, I seem to be talking myself out of it, because I really don't see a advantage. I'd love to drop a aluminum swingarm in it, but haven't found anything made for the 650 yet. Not sure it would be worth it, considering it won't be raced. It would be more for looks than racing.

I'm with you on the bearing updates, that's a must. Anything I can do to improve what's there, I will. Within reason, anyway. That's why I'm not sure the swingarm is worth it. I know what you mean about these things being a money pit. Then one day you look and wonder if it was worth it, wishing you had the old stocker back. But, what fun would that have been? Thanks for the input!

I understand your concerns, let me see if I get this typed out where it makes sense,

Motorcycling for me is a lifestyle every bike I have ever owned may have started stock but ended up reflecting my inidvuality. it is a passion while I totally respect and admire the quote purist. had I have bought a 78 KZ1000 in 78, or 79 brand new and owned it all these years I would keep it as it is/was

evry nut and bolt would be correct the only updates would have been ignition system. I wouldn't change a thing paint would be factory and pristine.

However I bought a cobbled up mess that several previous owners have abused and it quote being the original superbike has laid out an open palet. Franken Z is the perfect description.

the bike screams for a 30+yr old bike it has a mystique that it still is a badass. I had 2 otptios make it an extension of me or a complete restoration only to have the vision of a japanese designer from 30 years ago. and not even get a nod at show sitting next to one owner original paint bikes.

so the restoration doesnt make sense for my bike. If i were concerned about handeling performance, reliability my fat butt would be sitting on a ZX14 or comarable.

Street rodders will agree the 34 ford with the blower 9 inch ford rearend and the 4 link suspension isn't for the track its, for the WOW factor

my monoshock conversion with the ZX6 is sacrilidge to some who have maintaned there original KZ they bought new, and in a way I am cringing later this afternoon when I start cuttin the factory bracing out of the frame.

when comparing cost save your money and buy a restored bike in the long run it's cheaper.

However if your intention is to start changing parts to make it your individual vision Custom paint, differnt bodywork etc.. Then you ask yourself what your vision is?

as far as I am concerned I havent rode anything that rides or handles batter than a new bike let alone 30 year old designs so I want to complete the WOW factor. I already get plenty of smiles and comments at stop lights and local charity rides.

The cost cant be calculated as improving performance handling etc.. It has be calculated by is this what I invisioned?

For me it's the WOW factor and of course the "Mom look what I did"

ok just reread

Used swingarm
ZX6
Ebay and macine work under 200.00
Not finished yet estimating 500.00 (before I sell my take offs)

1. 3
2 N/A not finished
3 N/A not finished but so far yeah
4 1 it's therapy way cheaper than a shrink

hooked up with a beautiful cafe build not too long ago with original swinger
skinny tires It was a near perfect build. Clean lines and perfectly painted and polished is the secret in my opinion had I have been rich i would have stopped him and bought it lol
Cafes have a certain look that should stay true to the concept. in my mind

Krazy, I think I can lend some experience in this matter. I put a 95 GSXR 750 swingarm with 180/55r17 rubber on my KZ1000. I started out doing it just for the looks, but I can say this much. It doesn't handle bad. I'm no MotoGP rider, but I do own a modern sport bike that does corner well. My KZ with the mods starts dragging the exhaust at the header collector on right hand turns. Now keep in mind that I didn't just put on the swingarm. I grafted on the front fork from the same GSXR. I also braced my frame like to improve the flexibility that KZ1000's are known for.

The GSXR swingarm gives the bike a 2" stretch over the stock steel unit.

As for cost, I bought a donor GSXR with no title for $250 that got me most of the parts and got me through the mock up phase. Later, I had to buy a different set of fork legs for $200 since the chrome was pitted on the originals. I rebuilt the fork and the rear shock, and installed a Racetech Gold Valve Kit in the rear shock while I was in there. That was another $200 for the gold valve kit and seals, oil, etc. I also re-sprung the fork and shock for my weight, that was another $200 or so. Lots of little changes had to be made along the way. I used the mono-shock which necessitated a totally custom battery box. The front fork required that new steering stops be made to keep the legs from hitting the tank. Keep in mind that I did 100% of the work myself. If you cannot weld, and don't have the ability to machine bushings for the swingarm, then you will obviously be paying someone dearly for those services. I spent about a year working on my bike over nights and weekends to put it all together.

What I like about the conversion that I did: It handles fine, doesn't dive under hard breaking, I can take a long sweeper at high speed with no KZ death wobble. I love the modern brakes, modern tire choices, and the GSXR suspension is completely adjustable. It can be set up as firm or soft as you like. I absolutely love the look on my bike. It's exactly what I wanted.

What I don't like is that I still need to gain a little ride height that I lost due to smaller tires and shorter front fork. That's coming. It also took a lot of my time since I did all of the work. You are right to ask before you delve into this. I have seen quite a few really cool projects never make it to the road because it becomes too much work. I didn't even mention that you will need to work out offset sprockets and chain clearance issues when going to wider tires. I would rather see a guy ride his bike than wrench on it. If it's your only bike, then keep in mind that it will be down for a while. I had my ZX-10r running so I could still go for a spin to blow off steam.

All in all, I'm very happy with how my bike came out. Worth every penny to me. See for yourself.

Here's the rusty hulk that I started with:


An early mock up shot:


This is about where she's at now:






That last shot shows my newer rear sets, and I have since polished the aluminum a lot better. Hope that helps.
I documented everything in my build thread. The link is in my signature if you want to see what I did.

The stock KZ650 handles very well as is. Changing the length of the swingarm will not improve handling – shorter will make it twitchy; longer will make it like driving a school bus. I've owned my KZ650-C1 since new (April, 1977) and while I still ride in a rather spirited fashion, in my younger days I rode the bike with wild abandon. To fully exploit the handling characteristics of the KZ650 you must replace the shocks - they were the weak point. I replaced mine with S&W's (which I still have in a box) and later with Hagons. Quality shocks really wake up the handling. Also, the front forks work very well if you keep fresh fork oil of the correct amount and viscosity in them. I use Bel-Ray 15w fork oil. The other MAJOR factor is tires. In the good ole days I used Michelins with PZ2 racing compound. With those tires and the S&W shocks the bike would corner well enough to drag the centerstand tang, both foot pegs, and even the right hand muffler cover. Since then I replaced the steering stem ball bearings with tapered roller bearings (All-Balls) and replaced the swingarm bushings with new old stock bushings. The swingarm bushings work every bit as well as the later swingarm bearings, but some folks prefer the bearings over the bushings. In either case, keep them greased.

I would suggest if your bike has the original steering stem bearings, shocks, and swingarm bushings you should look at replacing them. Use high quality shocks – Hagons work very well as do some others, but don’t buy Chinese junk and expect good results. Also, find the stickiest tires available in your bike’s size. I now use 100/90 V 19 front and 120/90 V 18 rear Pirelli Sport Demons with Metzeler tubes. For many years I used a 130/90 v 18 on the rear, but it doesn’t provide better grip than the 120 because the narrow rim deforms the cross-section of the tire a bit. I tried the current Michelin tires (Macadams) and was bitterly disappointed. The Pirellis work very well. My bike still handles very well and I still occasionally surprise riders with newer, bigger bikes who maybe have slightly less time in the saddle.

Avon Road Riders also get some very very good reviews. One of the few brands making tires in the old sizes, too.

www.avon-tyres.co.uk/motorbike/z-650-c-f

Pressure front: 2.3 bar (33psi)
Front size: 3.25-19 54V

Pressure rear: 2.5 bar (36psi)
Rear size: 4.00-18 64V

ramtough_63:

That's funny you mention the "purist" vs the "WOW factor." I kicked around the idea of a total restoration for this bike. I thought long and hard about it for a couple of weeks. It wouldn't be all that hard, because most all of it is there. A set of pipes and lots of TLC would do the job nicely. But, as you say, that's not really me. Not that a mint 1979 KZ650 is a bad thing, it would actually be very cool. It's just not me.

At the age of 17 I conned my way into the pits at the Daytona bike race and purchased a full road race fairing from a vendor. The con was his creds to get me in to buy a fairing. If I remember correctly, I paid $150 for the fairing, belly pan and wind screen. I wish I could buy the same set-up for that price today! A month later it was on my '70 Mack III. Painted up exactly like the factory bikes. So, I guess you could say I've been pretty much into the WOW factor from the beginning. The long ago cafe builder in me ended up winning the stock vs WOW argument. My intentions are to build a KZ650 to look like a period factory ride. Right down to the slime green paint job.

The only hitch in my mind was the swingarm. If I can do a nice aluminum boxed swingarm for 2 to 3 hundred bucks, I'll do so. That's one of the reason I'm fishing here, is to see what others have done and if it's at all possible. To me, it would be the icing on the cake and finish the bike off nicely. I just don't want it to become a headache and a astronomical expense.

Thanks for your input!

testarossa:

Talk about the WOW factor! That thing was just short of a basket case. What a transformation! You've done some amazing things to your ride. Definitely one of the nicer overhauls I've seen. Super clean lines.

The one thing you've definitely done, is to modernize that beauty with all the up to date suspension parts. What I'm trying to do is incorporate some "WOW factor" and some "purist" at the same time. I'd really like to keep it as period looking as possible. So, I'm trying to steer clear of any major parts dumping. If I were to build another project bike, I would probably go that way. But, for now, I really want to stick to a period looking factory bike. There's just something about those Team Green rides that I always liked.

About that death wobble. I cut my street teeth on a '70 500 triple. You ain't seen nothin' 'til you've tossed that thing through some high speed turns. That was some fun stuff, if you had the stomach for it.



Thanks for your help and for the pix of your awesome ride!

650ed:

Ditto that. I will be doing all the things you suggested. I will also follow your recommendations on the tires and forks.

Thanks, the info is much appreciated.

DoubleDub:

Excellent, thanks for the info.