This will be the start of my new KZ650 project, which I eluded to a while back with my reintroduction thread. I foresee this being a bit of a slow build, but anytime I can dedicate time to it when im not at work (and when money allows it) I will update here. With that said...

Hello KZR, ever since I sold my first 78' KZ650 because of money issues, I've had that itch for two-wheeled fun fester in the back of my mind, and I knew I wanted it to be another Kawasaki. Fast forward to last year, and I pulled the trigger on a 1981 KZ650 frame. It was bare frame, and by bare... I mean totally BARE.  It has lived in the back of my Honda Element since last year due to my lack of a garage. 


It is a 1981 KZ650SR frame that was... probably destined to never see the road again. Which is why I felt like using this as the frame for my build instead of the plethora of still-running, and still factory/OEM+ styled bikes on marketplace. Some frame work will need to be done, mainly the entire back end needing a once-over, and the "cruiser hump" being straightened out. Im debating on whether to modify just that seat area, or just fully cut off the back end and weld up an entirely new section. I'll decide on it when its time to fabricate.

I saw it mentioned in a post concerning front end swaps, and absolutely fell in love with the idea, especially after seeing Dnel928's build from 2012. He picked up an 03-04 ZX-6R swing arm and similar year front end; forks, brakes, triple trees and steering stem.
kzrider.com/forum/11-projects/520339-dne...z650-fighter-project

I found the swingarm for cheap, and also the front end for cheap, though it is a newer 2007 front end with Nissin brakes, a sought after brake considered much better than the Tokico brakes seen on 2006 and older ZX6's. From what I understand from Dnel's thread, the steering stem has to be pressed out of the KZ's triple tree's and welded into the ZX6's triples in order to work (I'll need a KZ steering stem since this frame didnt even have the front end with it... it was THAT bare) and the swing arm, it looks as if he trimmed the frame and bored out swing arm to accept the KZ bolt, so all in all, both are relatively easy upgrades that'll enhance the suspension of the bike. 



(Yes, im storing these in my bedroom because I lack a proper workspace. Others have done it before, so I dont see an issue )

For the engine, the original thought was to keep it a 650 until I found a 1982 750 block for sale for super cheap. I had played with the idea of just popping a 750 head on a 650 motor, but then this came up for a steal of a price, and I couldnt say no. I think it was so cheap because the owner had already disassembled the top end, down to removing the pistons from the conn rods. If I remember correctly, he did offer the carbs with it as well, but I refused because im planning to go the fuel injection route. All of which will be ran by "Speeduino", an open source engine management system ran off of an Arduino board. They can support anything from one cylinder bikes/cars, all the up to... I believe 10 cylinder car engines, with Chevy LS's being a popular choice due to the sheer number of cars receiving the "junkyard Turbo LS swap".
 
 
 

So this is where im at right now, not much progress in getting my hands dirty due to the season and lack of garage, but, I have some of the major components need to get started. 
One thing im considering since the top end is already torn down, is to just bore it to 810cc. Its already taken down that far, and the stock pistons are already off the rods, and its a great upgrade (from what i've read) for the 750's, so why not? 
While I have the head and jugs off as well, I caught wind of the 6-speed conversion threads, which would be easy to do given the motors current state. Here, check out Daftrusty's write up of the conversion. Im really considering this mainly, just like he outlined, having a 6th gear for street use is fantastic. So enjoyable is it, that he even questioned why Kawasaki didnt just do this from the factory.
www.kzrider.com/forum/2-engine/607443-6-...on-swap-instructions

There isnt much more to report, I dont have a gas tank, wiring harness or any sort of body work for it yet, and thats due to those areas not having a fully formed plan for them. Sure there are ideas, but I dont want to fill this thread with a slew of half baked ideas. I want to keep it somewhat on the rails, with solutions that are already well thought out and can be acted on. 

I know this'll be a question, but I dont see this as a balls-to-the-wall race bike. This will be a street bike with enough pep and handling to be fun, as well as being an outlet to really create something unique with the body work. The entire starting point lends itself to that, being a frame that is essentially an empty canvas. I wont be destroying a perfectly good OEM example or tearing apart an already realized vision. It is by its nature, completely open to being something new.

You perhaps should heed riturbo's advise!! Sell it as a whole! Think about the time it's going to take stripping/photo'ing/listing and how much space it's going to take up once scattered about. Then all the money ebays going to remove off the top. What's going to happen, let me know, is You'll sell a few key parts and that's it..You'll be left with a pile of stuff that you can't even give away. Good luck either direction though! Does it have paper on it, read title? 

Hello KZR, I've had this account for almost a decade (And seeing some of the stuff I posted? yea... I was definitely much younger), back when I had a 1979 KZ650. But... I moved out of my parents house, to another state, money got tight and had to sell the KZ and my Honda CX500 and so, the account sat dormant for a while.

Recently, my life stabilized and calmed enough for me to develop a drive to get back on two wheels. With that, I told myself that if I get a bike, it'll be stripped completely down to the frame to be built back up in the image i'd like it to be. So instead of tearing apart one of the many crisp and clean examples, I decided to just... buy a frame thats already stripped completely. Nothing on it but a clean Ohio title. With that, im not destroying a good example of a stock KZ650, but also at the same time, i'd be resurrecting a "bike" that, otherwise might not have seen the road ever again.

So with that said, I have picked up a 1981 KZ650H (I understand "H" meant it is a CSR?) 


It is quite literally, just a frame with a title, and thats totally fine for my goal. I've seen some incredibly interesting stuff that i'd like to incorporate (KZ750 head and cams, 2004 Kaw 636 front end/swing arm, fuel injection using GPz750 turbo TB's, or something similar as there appears to be many options, etc etc)

But yea, im glad to be back, glad to have a bike again even if there is some assembly required, and glad to have something smaller than a C4 Corvette to tinker with.

Dunemaster wrote:

So I'm a mechanical engineering student that has made a buggy with a kz750 F LTD engine and I'm thinking about making big changes to the engine to attempt to make more power. I am planning on replacing my carburetors for fuel injection and add a turbo while I am at it. Id be aiming for a max hp of ~120. I'll be using a genuine Garrett gt1241 turbo for the conversion and I'm modifying the throttle bodies of a 2005 Yamaha r6. I have a spare engine which I plan to use the head of because of its mechanical tachometer which I should be able to use as a cam position sensor. Apologies that parts of my post may overlap with other posts I've seen on the site. here comes my list of questions so far:
Any and all input is appreciated! thanks for your help in advance.

I'm working on a turbo kz750 as well and can fill in some blanks. Kawasakik1e is working on a turbo project as well.

I have realized I am essentially recreating the GPZ750 turbo engine so what are the differences between the engine internals? I know they have more aggressive cams but what else? are there any compatible parts I should look into buying?

Does the GPZ turbo have a stronger transmission to deal with the extra torque the turbo gives? If so, how can I improve my chances of not blowing mine to pieces?

You are definitely going to need heavy clutch springs and better clutch disks (APE is what I used). You'll want a hydraulic conversion if you do this. There are lockup clutch options as well.
Also do the viton clutch rubbers, for sure. 
I am not sure where the undercut gears, HD head studs, MLS headgasket become necessary. I'm working my way up to 150hp, so I'll find out. I'm running two kz650 254 duration intake cams with slotted gears to reduce cam overlap to about half of stock, ie about 20deg now.

I know the GPZ turbo has lower compression than the stock kz750, should I lower it to be on the safe side? I know in the automotive world some opt to just double up head gaskets to lower compression. 

Probably. There are somethings you can do to maintain the higher compression with boost. E85 fueling or water/meth. I put in a 16g aluminum gasket instead of the stock base gasket considering my end goals. stock composite head gasket still.

because of extra heat from the turbo and reduced air flow because the engine is blocked by the rider I want to install a large oil cooler to help the engine stay cool. If I install a significantly large oil cooler I'm worried about how restrictive the oiling system will be with both the turbo and large oil cooler.

I blocked off the galley in the oil pan and installed an automotive style oil thermostat between the main galley and the rear oil pan port that allows for quick warmup but also good cooling when needed. There was a couple psi drop with this system if I remember correctly. 

oes anyone know if anyone has had problems with the oil pump being too weak? Has anyone installed a scavenging pump on their bike to combat a restrictive oiling system?

You should be concerned with how un-restricted the oil system will be with a turbo. stock oil pressure on the NA engines is around 8psi hot idle. most turbos want 10psi minimum. I modified my oil pump to about double the flow.
I used an external electric facet pump to handle the scavenging. I also designed an adapter plate to use a stock oil pump as a scavenge pump driven by the secondary shaft. 

switching to an EFI system will I need to upgrade my generator?

Ive run my EFI system on single and three phase kz650/750 generators without issue, but i am using a non-return PWM fuel pump which greatly reduces idle power consumption. LED lighting also helps.

mechanical tachometer which I should be able to use as a cam position sensor.

I designed an MJF nylon 3dprinted cam sensor bung for the kz650/750 cam covers. I have a couple extras, if you'd like to buy one. 
I also designed a laser cut and bent metal crank position sensor bracket that reuses the stock pickup. 

Are there any other performance modifications I should look into?

Dont be scared to port the head a bit. clean up the casting line roughness, taper out the intake runners to match the TBs (as possible). Improving head flow makes turbo power easier.

Is there anything else I should know before getting sucked too far down the rabbit hole? I'm aware there is quite a lot of work to be done fyi

Figure out your control system. If you're using ITBs, youll want to use tps based tuning with map adjustment for boost. Or switch to a single TB manifold with map tuning. Map with ITBs might work with something like this  efi.ttrignition.com/quadramap.html , but i havent been able to contact this vendor or try the idea.


 

This member (RIP) did a carb/turbo conversion :

www.kzrider.com/forum/11-projects/423436...-turbo-kz650?start=0

Lots of good info there plus he was trying to get a DIY scavenge oil pump working, not sure if it working or not because he got sick

I am not a turbo expert by any means but have collected some information over the years. I was going to put a Eaton supercharger on one of my builds (sort of similar) so I have investigated putting power adders on Z1 and 650/750 engines in the past.

Dunemaster post=910298 userid=65727As for my reason to why I am using the KZ750 shaft I have a conventional drivetrain, no chains that is.
 

First off, please post many many photos of your buggy. We'd love to see the details.

Second, you should absolutely do an EFI and turbo conversion on your KZ engine.  Why not?  Even if you blow it up, the process of getting it built and tuned and running will have provided you with a huge amount of knowledge and experience.  And you already have the engine in the buggy right?  Just do it.

Oh.  If you do want a later KZ650/750 oil pan with the oil cooler taps, I have one sitting around I'd be happy to send to you.

Dunemaster post=910298 userid=65727 

• I know Suzuki was able to make a high performance motor with the '86 GSX-R 1100 that was oil cooled. They had a high performance oiling system but it makes me reason that if I get enough volumetric flow of oil in combination with a large enough oil cooler I should be fine with cooling.

That's not necessarily true. The SACS GSXR engines were designed from the ground up with oil cooling in mind. They had internal oil sprayers to cool the underside of the pistons, and sprayers in the head to cool the combustion chambers. That type of targeted oil cooling does not exist in the KZ engine. Even the oil cooler itself was an afterthought, added much later in the engines evolution.  Even if you keep the oil very cool, it's not necessarily going to carry heat away from the top of the cylinder (piston crown and combustion chamber) fast enough to keep the engine cool.

en.wikipedia.org/wiki/Suzuki_Advanced_Cooling_System

The SACS system uses high volumes of engine oil aimed at strategic points of the engine, like the top of the combustion chamber, which are not typically well served by air cooling alone. In order to provide enough oil for both cooling and lubrication, the system uses a double-chamber oil pump, using the high-pressure side for lubrication of the parts (crankshaft, connecting rods, valvetrain), while the low-pressure, high-volume side provides oil to the cooling and filtering circuit. The oil removes heat from hot engine parts through direct contact, is pumped away and subsequently routed through the oil filter, followed by routing through an oil cooler before being returned to the main sump.

 

That was an enormous pain in the rear, WOW! But in the end, it is done and my problem is technically fixed.
to start, the clutch dampers were turbo shrunk, like raisins next to a grape. Attaching vids of difference before and after install.

the awful noise I was hearing went away after I cycled oil through the engine for a good 10 minutes, something just wasn’t lubricated and happy. My clutch also now VISIBLY separates, so if the plates are stuck at this point, I’ll just send it on the center stand and hope for the best.
now onto my final problem, SURGING IDLE!
who knows what it is, but I’m gonna hit the carbs with a clean as much as I can as the previous owner stripped every single bolt on the carb rack. Impact hammer didn’t work so I’m not gonna try to damage it further for now.
also going to take this opportunity to check how my carb boots are looking, because this is where I suspect my issue lies, since I had a kz650 that had the same bad boots.
anyways, thank you for the help! Even if it didn’t specifically fix my issue (it was me being impatient) I learned a lot about the clutch mechanism, and built some better modification skills and my tool variety(I will never do this again)     

Those dampers are in the secondary shaft.  Partzilla lists them as still available.  Another huge improvement can be gained by changing the rubber dampers in the clutch.  A guy on the KZ750 Turbo site sells them, or at least he used to.

After being out of stock for a couple of weeks I'm glad to announce I've got a fresh batch of Viton dampers ready to ship.

The cost is still $45 US for a set of six. Shipping costs can be found in earlier posts.

So if you're interested contact me at turbosteve84 "at" verizon.net. I'm in the US.

Thanks,
Steve

Injected wrote:

It did not work like that as far as vintage Japanese bikes, nothing like the car world special build houses. No Kawasaki 650 was ever done up like that from a dealership.
 

The only exception to that I can think of is the Z1R-TC, where an independent company added the turbo kit and paint, but it was then sold through Kawasaki dealers.