If you want to run a 160 tire you could pick up a zx6 4.5" rim which will hold a 160 tire. As far as the swingarm goes a suzuki gs1000sz (katana)from 82-83 or a regular gs1000 has an aluminum swingarm which will bolt right in with only two washers on each side to take up the space. This is what i am running on my bike. The only thing you will need to change is the rear wheel bearings and the rear caliper bracket. The small kz (650/750) have a 17mm rear axle where the larger brothers have a 20mm. The suzuki also has a 20mm axle. If you go into the archives i did a write of with pics of everthing you will need for this conversion.

The forks seems pretty easy to fit. I took the time to read about how other people have made this kind of conversion. The stock GSXR stem is quite close to fitting so I may have to press a new bearring guide into the KZ neck and then put in new bearings or possibly get a spacer machined and fit the old KZ stem to the GSXR tripples.

Right now i think the swingarm is going to be the big issue and I may have to look for a different one as twowheeledterror sort of suggested. The swingarm is 11 1/4in. wide at the pivot, and the KZ frame has only 9in. of room between the swingarm mounts so obviously I could not remove enough material from either surface without making it unsafe. Then there is the issue of having the front and rear sprockes and chain line up without any obstruction.

Thank you all for the advice, I'm going to have to keep thinking about this one.

I have a suz gsx 1100 swingarm on my 650, wasnt a great deal of hassle to fit it, I have a150 on it at hte moment but a 160 will fit no worries but I dont think that you will go much bigger than that. I have used the stock 650 axle and changed the bearing size to fit, also had to machine up a few spacers as the 1100 swingarm is shorter than the 650 one is between the frame, I ll take a few pics of the arm if you wanr.

Cheers

Dave

O.K Here is my 2 cents;
Chassis, I would stick with 18 wheels as the motor is wide by modern standards and you need the road clearance. I run 1984 GPZ 550 wheels on a 1983-4 Kz 750 L front end.If you want even lighter and wider wheels I would go with 1985-7 GSXR 750 wheels. The front discs are too wide and possible the discs may be rerivetted on the other side of the carriers.I would not change the rake as it works well as is.You could run a GS 1100 swingarm which is light. It is also about 3 inches longer.I havent personally raced with one but a friend has and says he liked the lenght.The seat pan is steal and if you could replace it with a 83-4 KZ 750(plastic) or something else that would save some weight. My bike weighs 400lbs so I think it will be hard to get it down to 350lbs. I would be content with 375lbsAnother choice for front forks would be 83 GPZ 750 (37mm) all you have to do is bore out the stock triple 1mm. If you use the same front wheel the spacer will also need to be shortened as the 83 GPZ 750 is 5mm wider than the 650 triples.
Engine, I think you should seriously think of 100hp as a reasonable rear wheel limit.There no one way to acheive that.Heres is what has been done by a friend who does alot of my work. KZ 650 motor with a wiseco 810 kit(cases need boring),head ported and reworked using 750 intakes and stiffer springs. CAms will have to be 83-85 gpz 750 or better.Carbs 29mm smoothbores.Now this motor produced 100 RWHP but the real surprise was the compression and the off corner power/response. The smaller ports really drive the fuel/air mixture into the combustion chamber.
Personally I would not bore out the motor over 810 as you may run into heat issues.The motor can aslo be built with the 750 head and you may get more overall HP but perhaps not the same drive out of the corners.If you want to through alot of money at the project I would recomend dual plugging the head.
I would stick with 29mm smoothbores or perhaps 31mm CRs but no bigger than that.

RomSpaceKnight wrote:

Hope you got or will get wheels to match fork and swingarm. Hate to say it but will look like s!@t with a 16" LTD back wheel. A spindly 19" front wheel and GSXR forks just as bad. A single sided swingarm, COOL. Big project to get to fit though. I like GSXR swingarms with twin shock mounts added myself. Much easier and cheaper. Also 3" over on length. Watch your geometry on frontend with new front end.

He's swappping a GSXR forkset on, so I'd assume he has, or will have, a gixxer front wheel. I don't think I've ever seen a inverted front with a stock wheel. lol

As for the swing, it's technically no different than getting most other modern swingarms to fit. The problem is putting together the wheel/drive assembly. It's VERY costly.

Adding a modern swingarm and then welding (which actually has effects on the integrity of the arm itself if not done just right metalurgically speaking) shock mounts to mount dual shocks on it is really kind of backwards in my opinion. But like I said, that's just my opinion. I think if you are going to put the single shock swing on there, you might as well go single shock. It drastically cleans up the lines of the bike.

Your geometry will definitely change, so take it easy the first few weeks. The forks are MUCH shorter, and your steering will be MUCH QUICKER!

Early GSXR swingarms might work. Typically get 3" over on length. Popular mod for KZ in my town. Twin shock mounts can be welded on. A 750 triple swingarm might be a cheaper option. Not sure if you could get a 180 tire in it though. Maybe a 160.

Hope you got or will get wheels to match fork and swingarm. Hate to say it but will look like s!@t with a 16" LTD back wheel. A spindly 19" front wheel and GSXR forks just as bad. A single sided swingarm, COOL. Big project to get to fit though. I like GSXR swingarms with twin shock mounts added myself. Much easier and cheaper. Also 3" over on length. Watch your geometry on frontend with new front end.

Hey, I'm A new member here as I recently purchased a 77 KZ1000 LTD. My plan when buying it was to turn it into a streetfighter. I have already bought a set of inverted forks from a 96 GSXR 750, and I have VFR 800 Single sided swingarm being shipped to me.

Has anyone here tried fitting a VFR swingarm to their KZ? I've seen pictures of it before so I know its possible. From the measurements I was sent it appears it is far too wide at the pivot.

I think I have a pretty good idea as to how I will fit the new forks. But the swingarm has me worried.Any advice would be apreciated.

Thanks

Switch, this is really a number of questions I will try and address...

"o.k. now to show my level of ignorance. I have 81 kz100m1 CSR. I have replaced rusted out oem pipes with 4 into 1 header and muffler. Jet kit installed, and individual breathing."

The Dynajet kit for this bike isn't really very helpful. You would be better served to replace the OEM jet needles and bump your pilot jets up one size from OEM and the main jets 3 sizes from OEM using genuine Mikuni jets. I am basing this on the use of a 4 into 1 and pods.

---

"My questions have to do with the exhaust return system. I have read that you can simply put plates in place of the reed valves. Then the whole Tingler can be chucked out."

I suspect by TINGLER you mean the smog junk. I have never heard this term used before. First, remove the plates over the reed valves in the valve cover. Remove the reed valves and put plates over the openings or reuse the OEM plates and plug the holes or connect a hose between the two outlets. You can see pretty blockoff plates on the APE web site at:
www.kzzone.com/billet.html

You then work backwards and remove hoses and the cannister that is vacuum actuated. You will be pulling the vacuum hose from your carbs that goes to the cannister and putting a vacuum cap on it (3/16" cap).

_________________

"Well, if that's true, what about the vent in the transmission?"

The transmisson and crankcase on your bike are shared and the vent is to vent the crankcase. I suggest you connect a hose to this vent and route it over your swingarm. Some folks like to put a filter on it so bugs won't climb in or something but since pressure is outwards, there isn't a problem I think. If you want a filter, go to an autoparts store and buy a fancy car crankcase filter which will slip right on the vent. I use a hose.

---

"Also, does removing this system remove the need for the vacuum hoses from carbs to fuel petcock?"

Not only does engine vacuum actuate your smog devices but it actuates your petcock. If you remove that vacuum hose from your petcock it will no longer work in the ON position. If you remove the hose you will have to run in the PRIME position and will have no way of shutting gas off. If you do this, plug the port on the carbs as it will just be a big vacuum leak and the carbs won't run right.

---

"Because of some other unrelated issues this has been a two year project that I really want to finish. I have never ridden or even heard this bike with this equipment!"

TWO YEARS? Go to local library and find a self-help book on overcoming procrastination! bwhahahaha

Here's my 2cents worth on your project....I think you are really gonna be on the knife edge of reliability with trying to squeeze 120 horse (at the wheel?) out of the 650/750 design. You didn't mention an oil cooler or pipe choices so I'll assume an oil cooler will be necessary and the pipe will run wide open on the track.

I am just beginning my winter 810 upgrade (already have the 700 Wiseco kit in the '77Kz650 Custom) with my goal being 100 streetable ponies measured at the crank. I am looking for a strong degree of reliability and longevity instead of wide open track performance.

In all of my engine upgrade research I haven't come across your suggested cylinder sizing or piston choice but degreeing the 750 cams is mentioned everywhere to properly set the valves after decking the head by 30 thou. This head trimming will also raise up the compression ratio slightly but you have to be careful not to bump the compression up too much unless you are going to be running some serious high octane racing gas.

I have read that the 650 ported head is a choice worth considering because of the increased velocity through the smaller intake runners. The bigger 750 valves should fit. Also look at the 750 Turbo springs and head gasket as they are more durable than stock 650/750 offerings. On the carb side I defer to KZr's resident expert wiredgeorge who has recommended Mikuni34's for my project.

If you stay with factory parts for availability the choice generally seems to lean towards the GPz750 cams as they are a little hotter from the factory, but on the exhaust side they run an electronic tach instead of a gear driven one that came on the Kz650/750. The crankcase cylinder openings will also have to be opened up to accept the 750 jugs.

To get to the magic 350 lb. mark you are going to have to swap wheels, go with an aluminum swingarm with double shocks, strip off every unnecessary wire, bolt and run helium in the frame (just joking.) Let us know what your weight reduction plans are as I have a buddy who drag races a '78 and his ride comes in around 375 lbs stripped down and he can't find any more lb.'s to trim off.

There are some extremely smart folks on this site (including fellow Canadian Steve Darlington) that have gone at least part way down the road you are looking to travel, but I don't think there have been too many that were successful at hitting the magic 120 mark in a 650 frame. I don't doubt the middleweight can take it if you can make it.

In the archives there are numerous threads on the big bore 650 platform including a link to the GPz site plus several members who thrash their tweaked 650's in vintage races.

Cheers-Colin Firth-Ontario Canada

Post edited by: reborn650, at: 2005/12/30 00:44