SOHC CB750 fuel injection conversion??

72texas350

72texas350

Been Around the Block
I have been searching for this and haven't really found the answers I am looking for.

I am starting to do all of the research for my next project and some of it is somewhat out in left field. The project is my 78 CB750 that I totaled back in October and luckily had bad luck selling. One thing I was looking into is converting the bike from carbs to fuel injection.

I already have to tear down and rebuild the engine and figured that some of the work for a conversion like this would be easier to do while I'm rebuilding.

What all would I need to do to make this happen?
 
hmmmmm...... probably a lot of work..... not sure what benefit you'd get other than a consistent a/f ratio, which you can get pretty close to with well tuned carbs... my guess is that you're going to need a mill lathe and welder, some experience with electronics, preferably some experience writing some basic code for embedded mcu's, and a metric fuckload of free time to make it work right
 
EFI from Gixxer 600 is almost a straight swap, but it does take a bit of know-how, plumbing, and wiring to get it working.
 
Yep it's been done and well documented on the sohc4 site.
Mostly a work for the sake of work type thing.

No idea why rebuilding the engine would make it easier though.
 
I highly suggest you stick with well tuned carbs before dropping $1200+ on the fuel injection equipment just to say you can. Take that cash and invest in better forks, shocks, and brakes.
 
joeschuit said:
I highly suggest you stick with well tuned carbs before dropping $1200+ on the fuel injection equipment just to say you can. Take that cash and invest in better forks, shocks, and brakes.
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more true then bent.
 
I was already planning to throw on a front end from a GSXR and a couple other upgrades. I was just asking about switching to fuel injection for the heck of it. I'm defiantly not set on switch, just curious about how much work it would take and any benefits there might be.
 
Grab a Microsquirt controller. I'll sell you a set of GSXR600 throttle bodies and injectors with secondary throttle plates removed (the shaft holes will need to be plugged - and easy task) and go for it. The hot tip back in the day was Hilborn mechanical fuel injection. Those are still good systems but an electronic system is far better and not too hard to set up.

I may still have the ambient air temp sensor and MAP sensor as a once in a lifetime deal.

Or go up to larger CV type R1 system which I am about to put on ebay. Both were for a cancelled project.
 
72texas350 said:
I was already planning to throw on a front end from a GSXR and a couple other upgrades. I was just asking about switching to fuel injection for the heck of it. I'm defiantly not set on switch, just curious about how much work it would take and any benefits there might be.
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just ride the gixxer then :/
 
Bert Jan said:
just ride the gixxer then :/
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I am putting the GSXR front end on because I need to fix my bike anyways since I totaled it back in October. I like the GSXR type front end, but I love my old bikes. I just figured since I'm already rebuilding I might as well try to make a pretty cool frankenstein's monster of a bike.
 
72texas350 said:
I am putting the GSXR front end on because I need to fix my bike anyways since I totaled it back in October. I like the GSXR type front end, but I love my old bikes. I just figured since I'm already rebuilding I might as well try to make a pretty cool frankenstein's monster of a bike.
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hahaha go for it then!
 
I say go for all the crazy ideas you're curious about. I love when people do something for the sake of doing it and this would definitely be interesting to follow.
 
Finnigan said:
I say go for all the crazy ideas you're curious about. I love when people do something for the sake of doing it and this would definitely be interesting to follow.
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Amen. I was just wondering if op was in it to win it, so i poked.
 
haha yah, my next project was going to be a little off the wall and i brought home a seized 78 750 myself...maybe I'll end up going this route also....
 
I'll be sure to make a build thread for this one once I get started. This project is definitely a do it because I can, or can figure it out, type of project.
 
When I bought that GSXR600 injection system I grabbed a Shop manual for that bike to start to get my brain around EFI and then I bought a book on motorcycle Fuel Injection that was 5 parts enlightening and 5 parts confusion. It took me a while to work out the basics and to decipher it. http://compare.ebay.com/like/360661725547?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

There's a huge body of knowledge that can be tapped.

It's easy to get lost in all the product offerings and the technology, but if you stick to a couple of known entities, it should be much easier to pull it off. Microsquirt is a good controller and GSXR600 throttle bodies are right sized for that app.

The biggest advantage of EFI is that it is possible to run much larger bodies without any of the side effects that would come from using the same size in carbs. Two strokes are less well suited to EFI but a 4 stroke 4 is an easy conversion.
 
Did you ever make progress on this? I am Looking to do the same thing as my carbs are looking real bad.

Sent from my SM-G930V using Tapatalk
 
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