Nate87 Posted March 2, 2020 Share Posted March 2, 2020 I have a 4th gen 750 and have been wanting to convert it to fuel injected but am having trouble finding kits any one got a idea or any feed back about this idea Quote Link to comment Share on other sites More sharing options...
Member Contributer TheLimey Posted March 2, 2020 Member Contributer Share Posted March 2, 2020 Megasquirt seems to be the go-to for most people doing such conversions. http://megasquirt.info/ Quote Link to comment Share on other sites More sharing options...
GreginDenver Posted March 2, 2020 Share Posted March 2, 2020 I've done two motorcycle carb to EFI conversions, a Kawasaki EX250 and a Suzuki GSF400. On both bikes I used the MicroSquirt V3 ECU. If I was doing an EFI conversion on a bike like the VFR750 with its unusual "V" configuration I would convert the original carb set into throttle bodies (which is what I did on my Suzuki GSF400 conversion project). The reason for doing this (instead of trying to engineer up a custom set of 4 throttle bodies into a functional "V" configuration) is that getting things like the throttle actuation linkage rigged to work properly and reliably (meaning: getting the linkage to simultaneously open all four of the "V" configured throttle bodies the exact same amount when you twist the throttle) is really, really difficult. Quote Link to comment Share on other sites More sharing options...
Member Contributer mello dude Posted March 2, 2020 Member Contributer Share Posted March 2, 2020 7 hours ago, Nate87 said: I have a 4th gen 750 and have been wanting to convert it to fuel injected but am having trouble finding kits any one got a idea or any feed back about this idea I understand what you want to do, ....But.... . I owned a 4th gen for 7 years and the carb fueling on it was very spot on, the engine ran sooo smoothly. When I checked plugs, they were the most perfect shade of tan you could want from any engine. ...... IMHO, it would be a shame to mess with what is a great stock fueling setup already. 3 Quote Link to comment Share on other sites More sharing options...
squirrelman Posted March 3, 2020 Share Posted March 3, 2020 not a good idea as you'll have problems that carbs don't have, and i's a needless expense, trading simplicity for complexity. ^^mr mello has it right. Quote Link to comment Share on other sites More sharing options...
GreginDenver Posted March 3, 2020 Share Posted March 3, 2020 27 minutes ago, squirrelbrains said: not a good idea as you'll have problems that carbs don't have, and i's a needless expense, trading simplicity for complexity. ^^mr mello has it right. Exactly what would those problems be? I can tell you that both of my carb-to-EFI motorcycles run better than they did on carbs. The best thing about my EFI converted bikes is that I can let them sit for months and they start right up (I've let them sit through a full winter with no more effort than hooking up a battery tender). I'm not saying that carbs aren't a fine solution for fuel delivery, they are fine. But some people just want to tinker and experiment and improve things, they like to have a project to work on. That was me. I didn't enjoy cleaning and rebuilding and tuning carbs, but I really like the challenge of configuring and installing and running a fuel injection system (tuning air/fuel ratios as I ride the bike around with a laptop computer hooked up to the MicroSquirt ECU). If you've got the necessary skills/knowledge/time/tools a project like this is a very fun and satisfying thing. 1 Quote Link to comment Share on other sites More sharing options...
GreginDenver Posted March 3, 2020 Share Posted March 3, 2020 And... and... and... and... When you add the MicroSquirt ECU you can also implement full ignition control, which allows you to custom tune the timing and dwell of the ignition coils. The OEM Honda ignition settings are really on the conservative side, there's more ignition advance that can be tuned into the bike without hurting anything. I installed "stick coil" (coil-on-plug) ignition on my EFI project bikes. The DENSO corp stick coils that Honda used on the CBR600RR were perfect for my projects. Quote Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted March 3, 2020 Member Contributer Share Posted March 3, 2020 1 hour ago, mello dude said: I understand what you want to do, ....But.... . I owned a 4th gen for 7 years and the carb fueling on it was very spot on, the engine ran sooo smoothly. When I checked plugs, they were the most perfect shade of tan you could want from any engine. ...... IMHO, it would be a shame to mess with what is a great stock fueling setup already. I don't think I ever had a bike or a car that ran more beautifully on carbs than my 4th gen. Honda absolutely nailed it with that setup. Ironically the benchmark for my 6th gen has been to get it running as smoothly as my 4th did. I finally got there but it took a lot of tinkering. Just asking - are the intake inlets on a gen 4 spaced about the same as on a 5th gen? I kind of doubt it as the cams' gear train moved from the crank center to the outer end, allowing the pistons to be closer together. If the throttle body would swap relatively easily that would get you good a ways down the road. Maybe custom TB boots? Another thing to overcome would be a fuel pump to supply sufficient pressure - I wouldn't think the 4th gen tank is gong to accommodate a pump internally. It will be interesting to see how this goes. Quote Link to comment Share on other sites More sharing options...
GreginDenver Posted March 3, 2020 Share Posted March 3, 2020 2 hours ago, Cogswell said: Another thing to overcome would be a fuel pump to supply sufficient pressure - I wouldn't think the 4th gen tank is gong to accommodate a pump internally. It will be interesting to see how this goes. Actually there's an all-in-one fuel pump solution that's available from Honda. It's a self-contained external (as in: not an in-tank pump) that Honda uses on its fuel injected TRX 4-wheel ATVs and on their big V-twin cruiser bikes. It's an aluminum housing that includes an electric fuel pump, a 43psi fuel regulator and a "sock" type fuel filter. There are two versions of this fuel pump, one is for engines up to about 550cc and the other is for engines up to 1300cc (the big VTX 1300 cruiser bike). The two versions are externally identical, just the pump volume is different. I used the lower volume version on both of my EFI project bikes, one is 250cc bike while the other is a 400cc bike. 1 Quote Link to comment Share on other sites More sharing options...
Member Contributer Marvelicious Posted March 3, 2020 Member Contributer Share Posted March 3, 2020 19 hours ago, GreginDenver said: And... and... and... and... When you add the MicroSquirt ECU you can also implement full ignition control, which allows you to custom tune the timing and dwell of the ignition coils. The OEM Honda ignition settings are really on the conservative side, there's more ignition advance that can be tuned into the bike without hurting anything. I installed "stick coil" (coil-on-plug) ignition on my EFI project bikes. The DENSO corp stick coils that Honda used on the CBR600RR were perfect for my projects. I've followed the Megasquirt project since its early days and it has come a LONG way. It's really an amazing piece of gear. I've occasionally considered using it in place of my 6th gen ecu/power commander to get full tune-ability, but then I come to my senses and realize I have a perfectly running bike and enough other projects to last 3 lifetimes. First: do no harm. Quote Link to comment Share on other sites More sharing options...
Smack Posted March 4, 2020 Share Posted March 4, 2020 Thanks for that info, Greg. I concur with the superior 'tweakability' of the EFI setup. For an E-85 conversion, the EFI/timing looks very desirable. Still, I have a soft spot in my heart for those carbs (agree the '97 runs well on carbs!). Brian Quote Link to comment Share on other sites More sharing options...
TheAkbars Posted September 27, 2021 Share Posted September 27, 2021 (edited) I sure hope I can temporarily ressurect this thread. I'm sure it's many times easier than dealing with a V configuration bike, but how much effort do you think converting a CG125 would be? I'm pretty sure there's no way of getting an RPM signal considering there's no RPM gauge on the cluster making load calculations difficult. This isn't for a practical purposes, more of a project I find interesting. Edit: should mention that it's a '96 Brazil and is a CDI bike. Edited September 27, 2021 by TheAkbars Additional information Quote Link to comment Share on other sites More sharing options...
squirrelman Posted September 28, 2021 Share Posted September 28, 2021 anyone who can't deal with cleaning and rebuilding carbs and tuning them isn't gonna have the technical skills to custom design and install a fi system.......AND GET IT WORKING RIGHT. Quote Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted September 28, 2021 Member Contributer Share Posted September 28, 2021 16 hours ago, TheAkbars said: I sure hope I can temporarily ressurect this thread. I'm sure it's many times easier than dealing with a V configuration bike, but how much effort do you think converting a CG125 would be? I'm pretty sure there's no way of getting an RPM signal considering there's no RPM gauge on the cluster making load calculations difficult. This isn't for a practical purposes, more of a project I find interesting. Edit: should mention that it's a '96 Brazil and is a CDI bike. What's the purpose? There's always RPM signal, that's how ignition-system works. Use oscilloscope to probe the pick-up coil on crank. If oscilloscope isn't regular go-to in your toolbox, this will not be "easy" project. Really, only reasons would be to extract that last +5-10% performance out of engine over carbs. On CG125, you won't notice the extra 1 bhp. Or to tune for extreme mods such as turbo, turbo+supercharger, or turbo+supercharger+nitrous. All of which is much easier to tune with couple button-clicks of mouse when changing something like boost-level. But if you're staying with stock engine, factory carbs work just fine. Example is this custom-built turbo barstool with Honda 160cc single engine! Has SDS-EFI system, typically used on Lycoming aircraft. Most people wouldn't notice difference with more lively partial-throttle response from 3D mapping of ignition. Here's links to Greg's really cool EFI conversions on Ninja 250 and Bandit 400: https://www.ninjette.org/forums/showthread.php?t=34208 https://www.ninjette.org/forums/showthread.php?t=54500 http://forums.banditalley.net/suzuki-bandit-250-400/greg's-bandit-400-fuel-injection-project Another Ninja 250 EFI turbo conversion and built his own dyno to tune it. http://swarfman64.blogspot.com/2015/01/ninja-gpx250-turbo-project.html Never, ever "easier" than carbs due to time and cost involved for minimal gains. Easiest is buying all EFI parts from similar bike and retrofitting to your own. Such as EU EFI Ninja 250 vs. U.S. carby Ninja 250. After U$3000 - 3500 in parts and expensive software. Along with hundreds of hours in labour, you have bike that behaves exactly the same with similar output. Only when you start upgrading the bike with full-exhaust, cams and high-compression big-bore pistons, then EFI lets you adjust tuning easier and gain some little extra over carbs. In case of Ninja 250, it's an extra 5bhp over what carbs gets with all these upgrades. Again, will you notice this extra 5bhp? That's less than difference between clean vs. dirty carbs on Ninja 250 anyway. "Easiest" upgrade is to send your carbs to squirrelman for cleaning. Megasquirt manuals are good reading for intro to EFI conversions and tuning: https://www.msextra.com/manuals/ 1 Quote Link to comment Share on other sites More sharing options...
TheAkbars Posted September 28, 2021 Share Posted September 28, 2021 2 hours ago, DannoXYZ said: What's the purpose? There's always RPM signal, that's how ignition-system works. Use oscilloscope to probe the pick-up coil on crank. If oscilloscope isn't regular go-to in your toolbox, this will not be "easy" project. Really, only reasons would be to extract that last +5-10% performance out of engine over carbs. On CG125, you won't notice the extra 1 bhp. Or to tune for extreme mods such as turbo, turbo+supercharger, or turbo+supercharger+nitrous. All of which is much easier to tune with couple button-clicks of mouse when changing something like boost-level. But if you're staying with stock engine, factory carbs work just fine. Example is this custom-built turbo barstool with Honda 160cc single engine! Has SDS-EFI system, typically used on Lycoming aircraft. Most people wouldn't notice difference with more lively partial-throttle response from 3D mapping of ignition. Here's links to Greg's really cool EFI conversions on Ninja 250 and Bandit 400: https://www.ninjette.org/forums/showthread.php?t=34208 https://www.ninjette.org/forums/showthread.php?t=54500 http://forums.banditalley.net/suzuki-bandit-250-400/greg's-bandit-400-fuel-injection-project Another Ninja 250 EFI turbo conversion and built his own dyno to tune it. http://swarfman64.blogspot.com/2015/01/ninja-gpx250-turbo-project.html Never, ever "easier" than carbs due to time and cost involved for minimal gains. Easiest is buying all EFI parts from similar bike and retrofitting to your own. Such as EU EFI Ninja 250 vs. U.S. carby Ninja 250. After U$3000 - 3500 in parts and expensive software. Along with hundreds of hours in labour, you have bike that behaves exactly the same with similar output. Only when you start upgrading the bike with full-exhaust, cams and high-compression big-bore pistons, then EFI lets you adjust tuning easier and gain some little extra over carbs. In case of Ninja 250, it's an extra 5bhp over what carbs gets with all these upgrades. Again, will you notice this extra 5bhp? That's less than difference between clean vs. dirty carbs on Ninja 250 anyway. "Easiest" upgrade is to send your carbs to squirrelman for cleaning. Megasquirt manuals are good reading for intro to EFI conversions and tuning: https://www.msextra.com/manuals/ Appreciate the reply, plenty of resources I haven't come across on my own. I should have also mentioned that, yes, I will be going bigger bore and higher compression. This isn't a project of practicality, but something to challenge myself and have fun tinkering with. I knew there would be some form of RPM, I just assumed it would be a massive pain to access, but I guess I'm here for that. The extra single horsepower on a bike that's probably only putting out seven at this point would probably be noticeable. Once again, thank you very much. Quote Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted September 29, 2021 Member Contributer Share Posted September 29, 2021 You're welcome! If you're doing aftermarket EFI, then you can use any trigger wheel off crank for speed & TDC reference. Many systems have programmable trigger patterns that may match what your flywheel has. A lot of people will weld a 60-2 wheel onto their flywheel. Pumps & injectors are next challenge. Calculate max-flow at 80% duty-cycle of injectors. Many people pick too-large injectors and have trouble getting short enough duty-cycle for idle. Searching Megasquirt forums will yield answers to pretty much any any question you may have. https://www.msextra.com/forums/ Good luck with your project! 1 Quote Link to comment Share on other sites More sharing options...
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