Q's about proposed KZ750 EFI turbo engine

I would seriously consider getting the combustion chambers and the piston crowns and skirts ceramic coated to protect them from the added heat.

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.


 

That is a really cool build saablord! I've been doing some research into my options and I have come to the hesitant conclusion that the build may not be worth it for my purpose. I found out about the existence of the Kawasaki 1000 concours. The engine fits all the criteria I'm looking for while being water cooled. From what I have read the concours' engine is essentially the motor from the ninja of its day tuned for torque and has a shaft drive output. Having seen on the cog forum that these bikes often survive hundreds of thousands of miles, I think I know what I'll be searching for on Facebook Marketplace in the foreseeable future. In case anyone is interested I'll make sure to keep this post updated on what road I decide to go down.

Haha yes, I have come to the same conclusion (air cooled motors not being worth it), but I'll still finish out my build.

Watch out for wrecked Concours motors as they quickly destroy themselves from oil starvation (ie when they're running on their side after a crash). Checkout this forum forum.concours.org/index.php?threads/

As an aside, Kawasaki produced a DFI GPz750 (Z750-V1(GP)) in 1981/2 for Japan-only sales.  This model morphed into the 1982 GPz750 (KZ750-R1) normally aspirated motorcycle that the world received. I have the parts manual for this Japan-only model and although the the manual (Kawasaki part number 99911-1055-03) is in Japanese, the part numbers and exploded diagrams are there and easily interpreted. The sections on the FI may be of value.  

Saablord wrote:

Watch out for wrecked Concours motors as they quickly destroy themselves from oil starvation (ie when they're running on their side after a crash). Checkout this forum forum.concours.org/index.php?threads/
 

For any DFI build I suggest running a tip over switch/sensor. Its function is to cut-off power to the injection and ignition systems in case the machine is tilted too far from the vertical, too far meaning roughly over 65º inclination from the horizontal or indeed fall flat on its side completely.

I have one wired into my fuel injection harness taken off a ZX6, its a simple switch that has "V" shaped internals and a sliding contact which will brake the circuit if tilted too far.