I read thereview in Motorcycle dailyon the Nightster. Thewriter made the comment that the F.I. "really woke theSportsterup". Althoughengine performance numbers fromHarley don't seemed to have changed between Carb and F.I.
I am just curious ifanyone has owned a carb Sportster and now own an F.I. model and can vouch forboosted performance? I don't doubt that "feeling" is everything and I am sure the F.I . feels crisper over a carb.I haven't noticed anyone with Dyno figures on 07-08 modelsin recent treads to compare with pre-07 models.
Just curious...
I have a Nightster and did ride an05' 1200C but it was years ago, my memory is foggy but I remember the ride and power feeling completely different than my bike.

 

I can't comment on the Genuine HD EFI v. carb systems, but when I converted the 883 from a carb to EFI, it made a tremendous difference. I think it has more top end, but the biggest gain is in driveability and low end power, which is way up. That's going from a S&S Super shorty (best of the 3 carbs we've had on that bike) to a MegaSquirt controlled system with the Buell intake/throttle body. My wife's comment the first time she rode it was "It's like an automatic transmission. You just put it in gear and go."

 

Dr Hess...We are interested in doing that to our Sporty..Can you give us some more info on the MegaSquirt system? What do we need to get, all the important stuff....Thanks..

 

Well, it was quite a job. The particular MegaSquirt I used is really a "derivitave work" version. Some guys, one in Ohio and one in Oz, worked out what the minimal needs were to run a Buell on a Megasquirt system, then designed a circuit board that had only those parts and used mini everything (caps, resistors, etc.). Here's the MegaSquirt based computer:


I went with this because the Microsquirt was still in development and due for release "any minute now" for a year or so and I got tired of waiting. I believe the Microsquirts are now shipping, so, really, that would be the way to go as the unit would then be prebuilt for you and about the same size.

I bought an intake system on Ebay off of a 99 Buell XB, I think. I don't know my Buell models. It has the intake manifold with injectors and rail and throttle body. It bolted right up to the 87 883 heads, no problem. The injector plugs are the same as a Ford, and the throttle position sensor is the same as a Ford V6 that was in a Mustang. I'd have to look at my notes for the year Mustang, but it was either an early 90's or a 80's if I recall. The fuel pump is from a Victory. I bought one on eBay. It was dead, so I bought another one new from the Polaris dealer. The fuel pressure regulator is a cheap adjustable one I bought on eBay. I'm not real happy with it. I suspect it might be a clone of a HK$ or something and I think I'll replace it with a better one. The pressure creeps on me. I made an adapter to interface between the Buell TB and the S&S air cleaner:



The fuel return line T's in between the tank and the Victory fuel filter that I use as a sump/surge tank of sorts. It is important to have fuel all the time with EFI, as there is no float bowl to have enough to get you a ways if all your fuel is sloshed to the back or side of the tank. This worked out fine in 2.5K miles so far. I am running Alpha-n code, which calculates the fuel needs based on RPM and throttle position, and currently do not have the fuel pressure regulator hooked to vacuum, as I used the Buell vacuum tap and it is in the wrong place to provide a true vacuum signal. The electrical system was right at the limits with all this, if not a tad bit on the "oh-oh" side. Stock 1987 883 output is only 18 amps. To compensate for this, I have the fuel pressure down to about 40PSI, which puts a lower load on the pump, changed the headlight bulb to a 35/35W one (slight decrease in headlight, not that bad, and that bulb is used on other jap bikes), and swapped out the rear turn signal/running lights to ones that draw 5W on the running light instead of the original 8W. Between all that, I saved about 3-4 amps. It's been doing fine. I don't know what the electrical systems of the later bikes put out. I also put a new tank on it, a 3.5-ish gallon one. We just leave the petcock in Reserve on it.


The oxygen sensor is a 2 wire unit as used on 90's Cadilacs, selected because it has a separate signal ground and has no heater for zero current drain. I welded the bung to the front drag pipe, as you can see in the pic. The cylinder heat temp sensor and the intake air temp sensor are thermistors that were a couple bucks each from Digikey. I epoxied one to a ring terminal and bolted it to the front cylinder head under the motor mount bolt in the middle of the motor, right side, and the IAT sensor is siliconed into a plug in the air filter backing plate. They have been working quite well also. The fuel pump relay is an extra relay I had laying around the shop from a Toyota. I also have a dual MAP sensor, so I have the ability to use

 

That is a freakin'awesome DIY project. Well done !

 

After 2 HD's with carbs ( both Keihin and Mikuni) which I enjoyed , I went to EFI and couldn't be happier . As I ride at a wide variety of altitudes I find the bike is much less effected my it , starts easier and runs more consistently over all.

 

From 1970 to 2006 every Harley I owned was carb'd, and I swore I'd never own a fuel injected model.....

But after I purchased my Softail FatBoy, installed a SERT, and had it dyno tuned by my friend, all I can say is that I'm very surprised with the performance and would never consider going back.

I love my older bikes with their carb'd engines, but my EFI FatBoy (and Road King) are just easier to get along with and much smoother... Just hit a button and ride, doesn't matter if it is 15 degrees outside or 115 degrees, and it doesn't matter if you are riding at sea level or 12,000 feet up in the mountains.

Made a believer out of me.

 

I definately like the EFI over the carburetor days.....

Didn't think I would ever want EFI on a motorcycle.....well, I wouldn't want it any other way now.

 

EFI is teh only way to go..evenMX bikesare coming out withit...so i dont think its jsut an emissions ploy...

 

This Street Bob is the first bike I've ever had that was fuel injected. I was just used to the carbs and didn't know any better but now I will not go back to a carbed bike. Like OFG said it is nice to just go out and hit the button and away you go. No more warming up the bike or hearing it spit back at you, it's great.