Carbuerated or Fuel Injected?

3686 Views 32 Replies 15 Participants Last post by HIPPO, Aug 17, 2002

Roadhwg

Discussion Starter · Jul 28, 2002

Well here's another fuel injected/carbuerated question to ask. I'm no mechanic, but I like to ride. The new 03' are in and most of them are FI's. I'm just wondering if a Carbuerated bike be just as good as a Fuel injected. Is there anyone out there mechanically inclined to give me some information. I feel like trading in my bike for an FI, everyone's talking about it? Let me know.

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FLHP

· #2 · Jul 30, 2002

I've got posession of both right now. I have a 2000 FL thats carburated, and a 2002 that has Fuel Injection. It's a little unfair, as the carb bike has other engine mods, but both bikes are the same model.

The fuel injection is nice, no warm ups, no chokes, and no coughing and sputtering. On the other hand, I like the throttle response of the carb. My specific gripe with fuel injuection, is that during rapid shifting, the engine rpms don't seem to drop as fast as when the slide goes down on the carb.

For every day ease of riding, FI is the way to go. If you ever plan on doing some engine work, go with the carb.

yzf996fxdwg

· #3 · Jul 30, 2002

Just sold my carbed wide glide for an EFI road glide. After watching my bike being dyno tuned with a power commander for new pipes and air cleaner kit I'm excited about some serious mods this winter. A trip to California and back from Vancouver BC spoke wonders about EFI and altitude changes. My vote is for fuel injection.

HIPPO

· #4 · Jul 30, 2002

EFI is nice, but you become much more dependent on the dealers.

EFI bikes can never match the driveability of a well set up carb, not even mighty Honda has been able to.

Roadhwg

Discussion Starter · #5 · Jul 31, 2002

Thanks all on your responses on the carb. It's refreshing to hear that carb'ed bikes are just as good as the EFI's.

BHBandit

· #6 · Jul 31, 2002

Gotta agree with Hippo about being dependent on the dealer, got an 02 Ultra Classic with EFI problems and have only the dealer to take it to as nobody around here knows anything about EFI. IMHO stay with a carb.

Paladin1

· #7 · Jul 31, 2002

Any ideas as to why Carbs are at leasr as good, if not better in many areas (response, driveability, etal) on motorcycles, but aren't even offered anymore on cars. Getting past emissions, I race Porsches, and NOBODY uses carbs (other than vintages classes where required). Could it be because the aftermarket tuners don't yet have the right (expensive) equipment? Not disputing it, just curious.

greg

HIPPO

· #8 · Jul 31, 2002

Race cars and bikes have a much narrower power band and it is easier to tune an EFI system instantaneously if cost is no concern. Max power under these conditions is about the same.
Bikes like the GSXR1000 and R1 have quite a different power to weight ratio then sports cars and minor drivability glitches become very noticeable, in part also because when leaned over on two wheels traction is much more critical. This is why despite running EFI they use various secondary computer controlled throttle systems that try to emulate the throttle response of carbs. In other words on a bike it is much more critical how the power is put to the ground.

Emissions force everyone into EFI, but it's how you use EFI. Some of the new japanese bikes are owner programmable from the LCD display while Harley purposely integrates EFI with other systems so it can not be diagnosed without proprietary dealer equipment. This is the part people do not realize, they are being set up for the kill.

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SIN

· #9 · Jul 31, 2002

I am just curious a friend of mine has EFI on his TC. I have a carbie on my twin cam. His is a 00 mine a 02 when you listen to both his seem to run very smoth at idle. And mine at idle sounds like it has a much more agressive cam profile ,longer duration. Does any one know if both EFI and carb motors run the same cams ?
By the way mine can out run his so far 3 out of three trys. Twice he hit the limiter in first and I had a hand full of second.
I do have VH. exaust with a Dyna jet kit and SE air cleaner, He said his needed to go back to the dealer it wasn't running right ,you guys and girls know that story.

HIPPO

· #10 · Aug 1, 2002

The HD EFI and carb cams have the same lift and overlap but the intake timing events are offset 4 degrees and consecuently intake lift at TDC is different. The EFI FLT's are also geared lower then the carb bikes. Even so with equal riders the carb bikes will run away from the EFI bikes, stock against stock, not by much, but they will.

Stock carburetor
-02/38 36/04 216 220 257 260 .473 .473 .072 .110

Stock injected
02/34 36/04 216 220 257 260 .473 .473 .087 .110

Honkylips

· #11 · Aug 1, 2002

Plus EFI bikes have a higher idle speed. The lower idle speed of the carb bikes gives them the more traditional po-ta-to po-ta-to idle sound. This kinda makes it sound like it has a more aggressive cam

SIN

· #12 · Aug 1, 2002

I wasn't sure with todays technology anythings possible. Thought it might help Roadhwg to throw a question in to help get some more information on the difference between the two.
Here"s another one on a EFI motor if you change the cams will the control module counter act the aditional fuel & air being added to the motor ? Or can you change the computer or recalibrate the map sensor the same way as an automotive performance module ? Just wonderin I'm stayin with my old school carb.
Like Hippo said the dealers seem to like the customers to be dependent on them and I'm just glad they still build carb engines.

logical

· #13 · Aug 1, 2002

HIPPO said:
Even so with equal riders the carb bikes will run away from the EFI bikes, stock against stock, not by much, but they will.

I suspect that is probably true...but I also suspect that once the aftermarket and/or Harley catches up and people start really getting into the right combinations of port sizes, fuel pressure regulation, maps, etc. that a well sorted out EFI bike will outrun a well sorted out carb bike. The carb will always be limited by the fact that it is a mechanical devce and operates very simply and one-dimensionally. Simplicity is why lots of people love carbs but that simplicity is also it's limiting factor.

HIPPO

· #14 · Aug 1, 2002 (Edited)

Maybe so, but I doubt it.

We specialize in EFI bikes and get higher numbers then most with them, not in some piece of literature, but on an actual dyno and on the road.

Discussing EFI and discussing EFI for a big twin Harley are two completely different subjects.

You have the built in limitation of engine (and to some extentbike) configuration.
It is very difficult to get clean vacuum signals on a common crankpin 45 degree two cylinder engine with the associated very uneven firing order and where the intake charge has to make sharp 90 degree turns without the possibility of fitting a large volume airbox. Now add that the Delphi system is primarily MAP dependent and you might begin to understand the problem.

Look at the throttle body arrangement on a Ducati where the intake charge and the injector has a direct shot at the intake valve and there is all sorts of room for an airbox between the V and you begin to see the differences.

When you are dealing with a fundamentally old fashioned engine configuration, regardless of how smart you might want to make it, simple might just be the ticket.

Don't get me wrong, I like working with EFI bikes and they make me good money, y'all go and buy one. I still like a carburetor on my personal bike.

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logical

· #15 · Aug 1, 2002

Good points Hippo about the V twins and their limitations, I was maybe thinking to much about EFI in general or in automotive applications.

Regardless, my EFI is so far, so good but the bike isn't and probably won't be heavily moddified....just stage 1.

cox9000

· #16 · Aug 1, 2002

This was another excellent thread but way over my head. I'll have to do some reading on my own so I'll get a better understanding. It does make me feel better about going carb because I did want EFI. The only reason I didn't go with EFI is because of the extra cost. I was thinking like logical, but now that HIPPO has educated me (again) I feel better about it. Thanks for all the input.

Roadhwg

Discussion Starter · #17 · Aug 1, 2002

Thanks all for the technical input eveyone has offered. I put this question out here cause I have numerous friends that both have Carbuerated and FI type bikes. I knew by putting this question out here would stir some commotion on the PRO'S and CON'S, which is an educational outlook for me and others who read the forum. Thanks all and keep em coming.

cox9000

· #18 · Aug 1, 2002

Roadhwg,
Thanks for posting this question, like you I learned something -- plus I have to do some more reading on my own to get the full concept. These kind of threads are what make this forum second to none.

Roadhwg

Discussion Starter · #19 · Aug 4, 2002

Your soo very welcome COX9000.

shag

· #20 · Aug 13, 2002

new to this forum, didn`t know where to go. Just got back from Sturgis. Road a 2002 flht with carb. Bike ran good but did run out of power in some of the windy conditions. rAN 70-75 most of the time in heavy wind. Had to run the bike hard to hold my speed at times. Hard enough that it blow oil out fo the aircleaner twice. Would like more power crusing in top gear at the 3000 rpm range. already done stage 1 but other wise stock. Any cam suggetions or other performace enhancments for this bike?

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