fuel injection

has anyone tried fuel injection on a xj 750 ?

 

Kiwixj750D owns an EFI 750..

 

Got a factory EFI XJ750, the so called D model.

The parts used are a temperaure sensor, fuel pump, air flow sensor in the airbox, "ballast" resistors for the injectors and a computer unit and of course the throttle bodys. These parts are rather hard to come by though.

Some pictures in my gallery.

 

Thanks

 

No problem, some more info here:

Dave's EFI XJs

Click on the pictures for details of the D and D2 models.

 

http://www.hal-pc.org/~dhutch/

Z sent this info when i asked about a bolt on fuel injection system for my bike.

 

I am thinking about going with microsquirt which is a megasquirt in a motorcycle-friendly form. It's smaller and has a more rugged enclosure and connector. It's missing the on-boards MAP which is a good thing in my book. External MAP can be used, but I suspect that you'd have to use Alpha-N for a motorcycle anyway.

Does anybody know, is the intake spacing on XJ1100 engines same as that on 700? I am thinking about getting 2005 GSXR 600 throttle bodies. They did fit Stan's XJ1100, I am wondering if they'll fit my watercooled XJ700.

I'd start the minimal amount of changes: retain the original yamaha VR ignition. Use megasquirt for fuel only. Just slap some throttle bodies, fuel pump with pressure regulator, ECU and a minimal number on sensors to make the thing work.

Then I'd loose the Yamaha ignition module, but retain the VR sensor - megasquirt should be able to work with it. I don't feel like butchering the bike to get the toothed wheel and better sensor in place. The immense amount of pain does not justify the minimal gain, IMHO.

 

Hey, if you get it to work let us know! I'm sure a LOT of XJ owners would love to dump their nightmare of a carb system for something reliable.

 

:?: XJ carbs are really, really simple if you understand them.

The nightmares you speak of are caused by owners.

 

XJ carbs are a rather simple design, that is true. They are Constant Velocity (side-draft) carbs. In the car world similar carbs are often called SU (Skinners Union), also Zenith and Stromberg by the name of the manufacturers. All of these carbs, at least in the car world, have a rather lousy reputation for being unreliable. That damn' rubber diaphragm is what kills the reliability. The fact that there's 4 of these damn' things and they need to work in sync does not help either. In the 70s cars used to have many carbs. It was bad for the customers, and good for repair shops. First fuel injection systems that appeared in 70s were junk too. By mid-80s and early 90s the electronics finally improved to the point where carbs became obsolete.

Working on carbs is like repairing a watch. Most people think that they can do it, it's not rocket science. The issue is being meticulous and understanding what you do, which is why there are so many botched DIY carb horror stories. Now, when it comes to fixing stock Fuel Injection, average mechanical skills are good enough. Retrofitting Fuel Injection to a work on carburated engine is a different story - it's an engineering challenge.

 

I knew a guy from Ohio that moded a DFI unit from a Kawi to a Honda...why not to a Yamaha. I had a Gpz 750 turbo years ago...the fi worked flawlessly.