TOPIC:

I'm a new KZRider member based in the UK. I've recently bought a 1980 KZ1000G - Z1 with whats left of the Fuel Injection system.
The bike was imported from the US (this model wasn't sold here). From what I've read the EFI wasn't good to start with and most were converted to run on Carburretors. EFI spares are non-existant in the UK.
I'm looking for advice on the conversion. Is it better to ditch the EFI head and replace with a Carb head or can Carbs be fitted to the existing head with the injector holes blanked off??

GriffKZ1000 wrote: I'm a new KZRider member based in the UK. I've recently bought a 1980 KZ1000G - Z1 with whats left of the Fuel Injection system.
The bike was imported from the US (this model wasn't sold here). From what I've read the EFI wasn't good to start with and most were converted to run on Carburretors. EFI spares are non-existant in the UK.
I'm looking for advice on the conversion. Is it better to ditch the EFI head and replace with a Carb head or can Carbs be fitted to the existing head with the injector holes blanked off??

Hello, GriffKZ1000, and WELCOME to KZrider!

Based on a Forum Search with key words convert fuel injection to carb, here's a link to some KZr articles about the conversion:
Click here > www.kzrider.com/forum/search?query=conve...orums=1&limitstart=0

Included among the above is the following:

Mcdroid wrote:

aphex wrote: I've been looking through the old posts on the forum for some answers but so far no dice. Hoping someone can help...

I've got a 1980 kz1000 g1 Classic, the American fuel injected model from 1980. Converting her to Mikuni VM28 carbs (without the accelerator pump). I'm new to fuel injection and new to these carbs. I don't have the carbs on hand yet and I'm waiting for a manual to arrive in the mail. A couple questions...

Do I need to run these carbs without the fuel pump and fuel pressure regulator, or do they need to stay in the fuel circuit somehow? I'm thinking of just letting the carbs run on a gravity feed and plugging the fuel return line to the gas tank, but not sure if this is correct.

Also, there are what appear to be vacuum lines running from the fuel injector holder to an "air flow valve" then to the front camshaft covers, as well as a larger line which runs from the air filter can. What are these for? I'll be running pods and doing away with the airbox and air filter can...want to make sure these vacuum lines aren't essential with a carb setup.

Aphex

Don't forget that the FI units mount directly to the head and that these ports must also be closed/epoxied shut. I have seen both approaches...epoxy and large threaded bolts .

Good Fortune!

Thanks for the help; I've read through most of the threads and it seems a reasonable fix.
One question; One of the writers refers to blocking up the Injector ports with "Clevis Pins" and a cover plate.
I understand the principle but what are Clevis Pins? Lost in translation? I'm guessing Con Rod/Piston connecting pins??

This is a clevis pin:




It has one or more holes that can take a reusable pin made of a springy material. Often they are used to secure something like a wagon to a hitch.

VM 26 carbs are cheap and run well on them.
Steve

Personally I would fix the issue with bodies. Far less to go wrong with the hardware than carbs, especially 4 carbs. There isn't much to go wrong with the bodies after all all they are is 4 tubes to mix the gas and air and 4 injectors. What usually goes wrong are the sensors for the ECU. I'm sure you could read the error codes by connecting the ECU to a laptop via an OBD2 interface and replace any faulty sensor. It may not be broke and that all you need is a suitable map which you could download from a Kwaker forum. IMO stick with fuel injection

OBD2 didn't come out until 15 years after this bike was made. It was a basic open loop system with few if any sensors. His problem is going to be finding parts. They're scare in the US. They're going to be really difficult to find in the UK.

VM 26 carbs are easy to work on and VERY reliable.
Steve

I've got a 83 GPz1100 that has been converted to carbs, as parts and the special diagnostic tools for these early FI systems are obsolete.

With yours, I am with Steve. Get VM 26's or 28's with the carb air box and associated bits and block off the injector holes with threaded bolts or aluminum plugs. I have a lathe and have made aluminum threaded plugs to close everything from injector ports to spark plug holes. When I first got the bike, I tried to get it inspected for certification with the injection removed and carbs installed. At the time, I was in a hurry and didn't have enough time to make all the block off plugs I needed. The only thing I could find that had the correct thread to plug the fuel return line in the bottom of the fuel tank was a 14 mm spark plug from my Honda. I put a plug cap on it too. just for fun.

When the inspector asked why there was a spark plug screwed into the fuel tank, with a perfectly straight face I told him it was the bike's self destruct mechanism. He just about blew a gasket himself "why in hell would you want to do that?" he asked. I said I was a MI-6 secret agent, and had to have "Q" custom install it, a machine gun in the headlight, and a passenger ejector seat...he still didn't get the joke.....

Decent CV34 carbs are difficult to find now, a worn out set will cause even more problems .

Most unrestored 30yr old bikes in the UK will have electrical issues due to corrosion, your EFI problem could likely be just a simple wiring fault.

The FSM covers diagnostics for all the sensors, there is no test for the ECU either than substitution so it is a case of double checking everything else before assuming the 'brain' is fried.

The GPz b2 DFI injection was an improved digital closed loop from the earlier variant. More info here:

Both the B1 and B2 featured Fuel Injection. The B1 model featured an EFI (electronic) system that was modelled on the 1980 z1000H and (also used in the 1980 z1000G model). This system was a hybrid car design using an air flap that had many reliability issues causing most owners to end up removing it and replace it with the 34mm Keihin CV carburettors used on all the later z1000 and z1100 models. The key problem with the EFI on the B1 was the use of an air-flap design rather than a MAP sensor used in modern systems and the early Throttle Position sensor (TPS) design registered only open or closed (idle) throttle positions. Later models (B2 and ZX1100A)featured DFI (digital) which used a variable TPS that accurately represented the throttle position and hence a better Electronic Control Unit (ECU) algorithm called Alpha-N.

On the B1 model, the four fuel injectors are mounted directly into the cylinder head above the inlet ports (hence the EFI system was referred to as port injection), while the B2/A (DFI) model had the more common Throttle Body Injection (TBI) where the injectors are mounted into the throttle bodies. With different throttle bodies comes a very slight difference in the air box mounting. The intake rubbers on the B1 are smaller than the B2 so a throttle body swap is not possible without replacing the inlet rubbers. They are also mounted at a 45 degree angle as the port injector openings are in the way.


en.wikipedia.org/wiki/Kawasaki_GPZ1100_B1/B2

Thanks for all the advice and sharing your previous experience guys.
My bike is a refurb project, the ECU(FI brain) is missing and as stated by MDZ1rider, parts aren't available.
If it was a newer bike with a better system I would try to keep the FI.
FI is the future and carbs are history on new designs.
With all the input from you guys I have the knowledge I was looking for.

Not sure about the self destruct device as par Kray-Z but I guess it depends how the bike turns out

GriffKZ1000:

Welcome to KZR...you should be aware that while the KZ1000G model was strictly a North American model, the equivalent model in Europe was the Z1000H model and the FI system should be virtually the same as the G model...H FI parts will be more available than the G model FI.