EFI for 1980 KZ750H1 LTD

Hey Guys!
The wheels in my head have been SPINNING since I found out about megasquirt and old bike EFI systems.

The old CV carbs and more so those %(%*#&$^ Airboxes are a total pain in the butt.

I'm so excited about putting an EFI system on my 1980 KZ750 I can barely contain myself.

Sorry to start a new thread on this but the ones I was looking at were from 2005 and I didn't want to revive any dinosaurs.

So someone in another thread was saying that the parts off of a GPz750Turbo will drop right onto the KZ750s. While this is all well and good, there are 2 things I would like to point out. 1)GPz750 parts seem rare and expensive 2)I woudn't want to steal parts from someone doing a resto on a GPz750 since they're so rare (biker karma ).

Are there any other fuel injected bikes with throttle bodies that will work on a KZ750?

What is typically being used for sensors? MAP/MAF existing on a TB from another bike? What about 02 sensors? My bike air cooled... do I need temp sensors?

What makes for a good/reasonably priced fuel pump/regulator?

Anyway, i'm doing lots of reading and have lots of questions! please help me out! :woohoo:

Cheers,
Mike

You can use the throttle bodies from a 1982(?) GPz1100-B2 (the one that doesn't have the injectors in the head).
These throttlebodies are a frequently used upgrade for a 750Turbo because they are a few mm's bigger...

Turbo throttlebodies go from 34mm at the inletside to about 29mm at the outletside.
The throttlebodies from the 1100 stay 34mm's all the way.

I have a set of both in my shed waiting to be used on my KZ700, and I was advised to use the 1100 TB's because they are a better size to use on a naturally aspirated 700 or 750.
The spacing on the TB's is the same, although you should use other carbholders to make sure the 1100 TB's stay where they are...
Also remember that the injectors used on the turbo and the 1100 are low impedance injectors, which means you have to adapt your Megasquirt to it.
You can also try to use some modern TB's, but then you'll have to adapt the spacing...

There are some people on this forum that already built a setup like this. I'm sure they will post here soon enough!
But if you use the search on this forum, you will find a lot of info on megasquirting old kawa's.

Hey, thanks for the reply! Lots of great information there and thanks for the heads up on the low impedance injectors.

If you havn't been to the Fi websites they are:

1. www.msefi.com
2. www.diyautotune.com

The summit racing website sells the MSD 2225 high pressure fuel pump and www.mpsracing.com sells a fuel pressure regulator that should work.

If you plan on using a set up similar to what the 81 and 82 GPZ's ran, you're going to have to install a fuel return on your tank. Mine is on the right side on the bottom with a one way valve so the system is pressurized to 33-35 PSI when the engine is running.

Hmmm... there are 2 lines comeing off of my petcock... can one of those be used as a fuel return?

Is this the fuel pump you're refering to?
www.mpsracing.com/products/MPS/FuelPumps.asp
48-15005 Motorcycle Fuel Pump $129.88

Can't a guy just use the GPz parts? fuel pump, regulator, etc?

I see no reason why you could not use the the old parts as long as they work. With your smaller engine getting it to run right will be a lot of trial and error.

I was really bored one night and came across this thread: kzrider.com/index.php?option=com_kunena&...ew&catid=4&id=253485

Some good info in there, and a very nice writeup from a guy who adapted his Yamaha Seca: residentialcolorado.com/SECA_750i.htm

You've probably seen the thread already, but just in case you haven't.

Yes you can use the gpz1100 hardware, the beauty of the gpz pump is that it uses 1.7amps while most of the others use at least 5amps and one of the major problems you will find is running the extra electrical load on a standard charging setup.

l0g1c wrote:

I was really bored one night and came across this thread: kzrider.com/index.php?option=com_kunena&...ew&catid=4&id=253485

Some good info in there, and a very nice writeup from a guy who adapted his Yamaha Seca: residentialcolorado.com/SECA_750i.htm

You've probably seen the thread already, but just in case you haven't.

Hadn't seen it and I'm readin' now! Thanks!
Dave Sloan wrote:

Yes you can use the gpz1100 hardware, the beauty of the gpz pump is that it uses 1.7amps while most of the others use at least 5amps and one of the major problems you will find is running the extra electrical load on a standard charging setup.

Oooo that's really good to know. I was wondering about all the extra juice requirements and it's good to know that the pump is the biggest offender.

Anyone happen to know if 07-08 ZX6 TBs will work? There is a stink pile of them on ebay for cheap... like $100 with sensors, wires, injectors etc.

I'm sure they can be made to work...
Spacing will be wrong though. Most modern bikes have the camchain on one side of the engine, so the TB's are evenly spaced. KZ's have the camchain between the cylinders, so the spacing between the 2 inside TB's is a bit larger..

But the biggest problem I think is the size of the ZX TB's. I think they are 38mm and unfortunately this is way to large for a 750...

Have a look at this page on the MS-forum:
www.msefi.com/viewtopic.php?f=29&t=6627
There is a lot of usefull info up there...

Paling1 wrote:

I'm sure they can be made to work...
Spacing will be wrong though. Most modern bikes have the camchain on one side of the engine, so the TB's are evenly spaced. KZ's have the camchain between the cylinders, so the spacing between the 2 inside TB's is a bit larger..

But the biggest problem I think is the size of the ZX TB's. I think they are 38mm and unfortunately this is way to large for a 750...

Have a look at this page on the MS-forum:
www.msefi.com/viewtopic.php?f=29&t=6627
There is a lot of usefull info up there...

Hey Paling1,
I actually heard that you wanted LARGER TBs for the 750 in order to get more power. I had a guy who did a conversion on a CB750 tell me that you want AT LEAST 38mm ideally up around 44mm....

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