1982 gpz1100 fuel injection

I have seen many injectors completely clogged up with tar. And yes, an adjustable fuel pressure regulator is a good way to go.

They run fine without the air box if you use the adjustable regulator. For a full on race setup, nothing beats the stock rubber velocity stacks that connect the air box to the throttle bodies.

Stock throttle bodies with the rubber stacks flow 125 CFM. Kawasaki knew what they were doing when they designed that system.

If you're going to keep the bike stock, leave then air box on. If you modify it for performance later on, you can go with individual air filters if you so choose.

If it were mine, I'd find some 83-85 GPz11 cams for it and drop them in. No need to switch to Shim on Bottom. They are the single item that will bolt in and provide immediate performance gains with nothing more than a valve adjustment. They're still out there and available for reasonable price. You'll want the adjustable regulator if you go that route.

If you go the adjustable regulator route, use the TPS adjustment to clean up the bottom end and make it idle smooth. Drill out the DFI cover plugs [carefully]. Remove the plastic cap. You'll see 2 phillips head screws with yellow paint on them. Warm up the bike. Set the idle to 1100 RPM. Adjust the TPS to where you have the highest, smooth idle & lock it down. Then reset the idle to 1100 with the main idle adjuster screw on the TB. That procedure applies to a bone stock bike as well. It's the best way to dial in the bottom end of the fuel curve. The little electric gizmo you see in the service manual for adjusting the TPS is good for taking up space in a drawer

cavanaughracing wrote: They run fine without the air box if you use the adjustable regulator. For a full on race setup, nothing beats the stock rubber velocity stacks that connect the air box to the throttle bodies.

Stock throttle bodies with the rubber stacks flow 125 CFM. Kawasaki knew what they were doing when they designed that system.

If you're going to keep the bike stock, leave then air box on. If you modify it for performance later on, you can go with individual air filters if you so choose.

If it were mine, I'd find some 83-85 GPz11 cams for it and drop them in. No need to switch to Shim on Bottom. They are the single item that will bolt in and provide immediate performance gains with nothing more than a valve adjustment. They're still out there and available for reasonable price. You'll want the adjustable regulator if you go that route.

If you go the adjustable regulator route, use the TPS adjustment to clean up the bottom end and make it idle smooth. Drill out the DFI cover plugs [carefully]. Remove the plastic cap. You'll see 2 phillips head screws with yellow paint on them. Warm up the bike. Set the idle to 1100 RPM. Adjust the TPS to where you have the highest, smooth idle & lock it down. Then reset the idle to 1100 with the main idle adjuster screw on the TB. That procedure applies to a bone stock bike as well. It's the best way to dial in the bottom end of the fuel curve. The little electric gizmo you see in the service manual for adjusting the TPS is good for taking up space in a drawer

What Larry said factory DFI is reliable and adjustable with TPS and a ADJ regulator I have done 750 turbos with 180RWHP with TPS setting and adj regulator W/O issues you do not need resisters just some common sense my own 84 gpz1100 is going to be 1170cc 10.25.1 cr ported head custom grind cams bored throttle bodies and a modified air box and good quality inj and it will as smooth or better than factory was.

DFIGPZ wrote: What Larry said factory DFI is reliable and adjustable with TPS and a ADJ regulator I have done 750 turbos with 180RWHP with TPS setting and adj regulator W/O issues you do not need resisters just some common sense my own 84 gpz1100 is going to be 1170cc 10.25.1 cr ported head custom grind cams bored throttle bodies and a modified air box and good quality inj and it will as smooth or better than factory was.

Your advice for FPR modifying the OEM DFI system is fine, and i'm sure it produces better results, but you guys need to understand, not everyone is a veteran expert KZ/DFI tuner. The original poster is obviously a novice asking for suggestions. The advantage of my "resistor mod" in this peticular case is a simple "bolt in and go" type fix, and if the mod for whatever reason does not work you simply unplug the resistor harness, and you are back to stock. (This is critical for me with my GPZ as I am maintaining 100% OEM original).

Polar_Bus wrote:

DFIGPZ wrote: What Larry said factory DFI is reliable and adjustable with TPS and a ADJ regulator I have done 750 turbos with 180RWHP with TPS setting and adj regulator W/O issues you do not need resisters just some common sense my own 84 gpz1100 is going to be 1170cc 10.25.1 cr ported head custom grind cams bored throttle bodies and a modified air box and good quality inj and it will as smooth or better than factory was.

Your advice for FPR modifying the OEM DFI system is fine, and i'm sure it produces better results, but you guys need to understand, not everyone is a veteran expert KZ/DFI tuner. The original poster is obviously a novice asking for suggestions. The advantage of my "resistor mod" in this peticular case is a simple "bolt in and go" type fix, and if the mod for whatever reason does not work you simply unplug the resistor harness, and you are back to stock. (This is critical for me with my GPZ as I am maintaining 100% OEM original).

NO, that's not exactly what you said. Here's what you said.

I've had a good amount of hands on experience with the DFI systems over the past few years and here's a few tips I can give you. Exp #1) The DFI systems do NOT like to be "air flow" modified in any way. You start adding pods, a pipe and now the crude air system monitors are all confused and cause very ill running. Either keep the DFI stock or swap to carbs. Exp #2) The DFI system is mapped pretty lean. I always had an annoying slight lean surging around 3100 rpm's. I corrected the problem with the DFI "resistor mod" . This is another reason to NOT sdd pods and/or a pipe. I even tried to block off the fresh air injection system and my DFI got all screwed up. I can comment my 27 year old DFI system runs mint.

Tossing the system for carbs because of airflow modifications is not required. DFI works if you know how to adjust it. Adjusting it is easier, quicker and a lot less messy that yanking carburetor racks and swapping jets.

The TPS adjustment is very basic. The hardest part is drilling out the 4 plugs that hold the plastic cover over the TPS. Adjusting the regulator can be done easily with a wrench also. Swapping out a stock one for an adjustable one takes less than 30 minutes.

For any GPz11 with DFI, adjusting the TPS is practically mandatory as the bike ages. It can make a big difference in the idle and throttle response.

Are you referring to a resistor that is taped up in the harness?

Larry C

cavanaughracing wrote:

Polar_Bus wrote:

DFIGPZ wrote: What Larry said factory DFI is reliable and adjustable with TPS and a ADJ regulator I have done 750 turbos with 180RWHP with TPS setting and adj regulator W/O issues you do not need resisters just some common sense my own 84 gpz1100 is going to be 1170cc 10.25.1 cr ported head custom grind cams bored throttle bodies and a modified air box and good quality inj and it will as smooth or better than factory was.

Your advice for FPR modifying the OEM DFI system is fine, and i'm sure it produces better results, but you guys need to understand, not everyone is a veteran expert KZ/DFI tuner. The original poster is obviously a novice asking for suggestions. The advantage of my "resistor mod" in this peticular case is a simple "bolt in and go" type fix, and if the mod for whatever reason does not work you simply unplug the resistor harness, and you are back to stock. (This is critical for me with my GPZ as I am maintaining 100% OEM original).

NO, that's not exactly what you said. Here's what you said.

I've had a good amount of hands on experience with the DFI systems over the past few years and here's a few tips I can give you. Exp #1) The DFI systems do NOT like to be "air flow" modified in any way. You start adding pods, a pipe and now the crude air system monitors are all confused and cause very ill running. Either keep the DFI stock or swap to carbs. Exp #2) The DFI system is mapped pretty lean. I always had an annoying slight lean surging around 3100 rpm's. I corrected the problem with the DFI "resistor mod" . This is another reason to NOT sdd pods and/or a pipe. I even tried to block off the fresh air injection system and my DFI got all screwed up. I can comment my 27 year old DFI system runs mint.

Tossing the system for carbs because of airflow modifications is not required. DFI works if you know how to adjust it. Adjusting it is easier, quicker and a lot less messy that yanking carburetor racks and swapping jets.

The TPS adjustment is very basic. The hardest part is drilling out the 4 plugs that hold the plastic cover over the TPS. Adjusting the regulator can be done easily with a wrench also. Swapping out a stock one for an adjustable one takes less than 30 minutes.

For any GPz11 with DFI, adjusting the TPS is practically mandatory as the bike ages. It can make a big difference in the idle and throttle response.

Are you referring to a resistor that is taped up in the harness?

Larry C

with my "resistor mod" all's I do is adapt a 1K ohm resitor wired into the air temp sensor circut plug . It provides a slight richening to the entire fuel curve. Crude, but simple, effective, and non-permanant. I got this tip from an owner of an old Kawi Voyager DFI owner...

BTW, I still have your head, it's still up in my attic, and I gotta remember to get the dam thing in the mail !

The air temp resistor can be replaced with a radio shack variable resistor. The draw back is the system needs to be rebooted for every change as I recall. Rebooted means key off / key on.

Truly the 83 DFI system is a good fueling setup and so much nicer to adjust than any rack of carburetors I've ever come across. I spent time recently dialing in a rack of RS34's. What took me 30 minutes with them would have taken me 30 seconds with DFI :lol:

Over the years I have been collecting components to build a few complete FI systems for these. At the moment I should have enough components to build three or four of them. The only thing that I am waiting on is fuel pumps which I will replace with new automotive ones. I also have adjustable fuel regulators for all.

otakar wrote: Over the years I have been collecting components to build a few complete FI systems for these. At the moment I should have enough components to build three or four of them. The only thing that I am waiting on is fuel pumps which I will replace with new automotive ones. I also have adjustable fuel regulators for all.

Are you looking for a OEM Kawi Jacs DFI pump ? I have 2 good spares, I think I can be persuaded to part with one....

Dear Larry!
Could you tell me how to adjust my DFI system? I have got adjustable fuel pressure regulator, new 300 LPH fuel pump, new datsun 280 zx injectors. Is a good way to put resistor in the engine temp sensor?

I have got a Gpz1100 B2 with a ZXT10A ecu. It is working good, but not enough HP. KZT10B and ZXT10A is the same I think. 

Larry C  passed on to the great  ride in heaven  a while back.

RIP Larry

Dave

My condolences to everyone who knew him and him family too!

Could Anyone tell me how can I adjust my dfi system? Is it a good idea to put a resistor to the air temp sensor harness?