Carb vs f.i.
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Definitely a case of "if you have to ask the question, you won't understand the answer"
My 98 RK is MM FI, with the stage II kit installed including the flash.
My friends with significant hotrodding done to their similar bikes ask me what's been done to my bike because I can walk on them at will.
A couple of weeks ago, I started the bike up after sitting for a year and a half, it fired on about a half revolution. I've started it in below zero weather with the same results. None of my carbed bikes would do that.
Once it had an obvious problem, which didn't stop it from running, but it did run like crap. I cycled the key three times, read the blinks and it told me it needed a new head temp sensor.
I've never had a carbed anything tell me what I needed to do to fix it.
In addition to the race presence, Magnetti Marelli is huge tier one supplier to the OEM manufacturers and there's a good chance they have stuff in your car.
I work with race fuel injection systems, and I've toyed with making changes to the system, but honestly It's not really broken, and very reliable. I'm old enough to force myself to not tinker with things that don't need fixing.
There is a system out there that will directly tune our bikes, I've seen it and touched it, but the license for it is blindingly expensive.
The only drawback of the MM (And the early Delphi IIRC) kits are "Open Loop", that is they don't use feedback to adjust the fuel tables but just run a static map.
I've pretty much decided not to poke at it, because it's so reliable and really goes as fast as I wan on a touring bike.
That's one of the reason I keep toying with the idea of building an insane FX...
My friends with significant hotrodding done to their similar bikes ask me what's been done to my bike because I can walk on them at will.
A couple of weeks ago, I started the bike up after sitting for a year and a half, it fired on about a half revolution. I've started it in below zero weather with the same results. None of my carbed bikes would do that.
Once it had an obvious problem, which didn't stop it from running, but it did run like crap. I cycled the key three times, read the blinks and it told me it needed a new head temp sensor.
I've never had a carbed anything tell me what I needed to do to fix it.
In addition to the race presence, Magnetti Marelli is huge tier one supplier to the OEM manufacturers and there's a good chance they have stuff in your car.
I work with race fuel injection systems, and I've toyed with making changes to the system, but honestly It's not really broken, and very reliable. I'm old enough to force myself to not tinker with things that don't need fixing.
There is a system out there that will directly tune our bikes, I've seen it and touched it, but the license for it is blindingly expensive.
The only drawback of the MM (And the early Delphi IIRC) kits are "Open Loop", that is they don't use feedback to adjust the fuel tables but just run a static map.
I've pretty much decided not to poke at it, because it's so reliable and really goes as fast as I wan on a touring bike.
That's one of the reason I keep toying with the idea of building an insane FX...
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,078
Likes: 2,150
From: Ohio
Have ran M&M and carbs on the same engine, the M&M is great for what it is designed for and common failures that are easily repair but it can also throw a good EFI diagnose tech out of bounds when the uncommon failures are present.
Had a modded plenom M&M system, Powercommander and making my own maps with a Daytona sensors Wego 3 tuning system, the M&M ran out of fuel delivery capability in a higher HP application but once again, it is great for what it is designed for. Crossed to a CV and now a Mikuni 45, both carbs clearly out perform the M&M with the 45 edging the CV. Wide open throttle and roll on AFR's were set the same so both were tuned the same, can only say that my M&M was trouble free even when it was pumped up but won't go back to it after bolting on caveman technology.
Now if were talking Delphi and a Mastertune, the carb met it's match
Had a modded plenom M&M system, Powercommander and making my own maps with a Daytona sensors Wego 3 tuning system, the M&M ran out of fuel delivery capability in a higher HP application but once again, it is great for what it is designed for. Crossed to a CV and now a Mikuni 45, both carbs clearly out perform the M&M with the 45 edging the CV. Wide open throttle and roll on AFR's were set the same so both were tuned the same, can only say that my M&M was trouble free even when it was pumped up but won't go back to it after bolting on caveman technology.
Now if were talking Delphi and a Mastertune, the carb met it's match
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,078
Likes: 2,150
From: Ohio
Fuel delivery in the 45-55 roll on area was maxed out on the Powercommander and still running lean, calling for additonal fuel by a recorded AFR table determined by a sampling AFR O2 sensor, detonation was present and timing was removed in that area, the Mastertune uses the same principle for DIY tuning in it's features.
The M&M with red injectors was very capable delivering at wide open throttle but struggled in throttle roll on area, could only get the AFR down to 14.8 with 100%fuel in that map area, less compression won't be a problem for the M&M but the carb has been better for my application which was hovering around 10.2-1 at the time. The EFI started easily in Ohio winters and never had a hiccup so going to stand by it is a pretty good system except I was asking alot out of it and the fuel dumping ability of the carb worked better.
The M&M with red injectors was very capable delivering at wide open throttle but struggled in throttle roll on area, could only get the AFR down to 14.8 with 100%fuel in that map area, less compression won't be a problem for the M&M but the carb has been better for my application which was hovering around 10.2-1 at the time. The EFI started easily in Ohio winters and never had a hiccup so going to stand by it is a pretty good system except I was asking alot out of it and the fuel dumping ability of the carb worked better.
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,078
Likes: 2,150
From: Ohio
Have installed Mastertunes ($450), Powercommanders ($325), Fuelpaks ($250) and very neat gadgets that will give obsessive AFR number guys their fix, my caveman fuel drip runs all day with these EFI bikes and close to mpg plus a sleeper in giddy up. Would I install a modern EFI for $125, heck ya but no possibility to convert without selling a kidney so will keep both kidneys to filter beer and keep the carb.
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Elite HDF Member
Joined: Apr 2007
Posts: 3,766
Likes: 16
From: Roseville, CA
But with modern technology, it's an apples to oranges comparison.