Carbs vs FI if you could choose.... - Wrist Twisters
 
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post #1 of 19 Old 11-01-2010, 09:08 AM Thread Starter
(Quintus) Pilus Prior
 
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Carbs vs FI if you could choose....

I have read, usually in a Brit mag, how quite often an existing bike got revamped. Now it's FI-ed. Now it's all herky-jerky. The carbed version was better.

My own experence is the used 599 I bought. I put on a can and rejetted it. It runs really well. I can't put my finger on it, but, a carbed bike has just a little different "personality" than a FI-ed bike.

I like the idea of no fuel pump, no pressure regulator, a lot less ECU, not nearly as many sensors to potentially go wrong. Simplicity.

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post #2 of 19 Old 11-01-2010, 10:34 AM
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Carbs--simplicity & no on/off throttle.

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post #3 of 19 Old 11-01-2010, 11:08 AM
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f-i all comes down to how it's programmed in the ecu. simple as that. my carbed vlx has a fuel pump and while it's different, i can make adjustments on the fly. i'll take f-i anyday

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post #4 of 19 Old 11-01-2010, 11:32 AM
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Hmmm, now lets see ......Carbs have all the following in terms of shaping the fuel delivery curve
Air Bleed Port
Pilot Jet
Slide Cutaway
Float Height
Needle
Needle Height
Needle Jet
Emulsion Tube
Main Jet
(I've left out synchronization as it is not a fuel delivery curve shaper)

As much as I love carbs, the above is, well, a bit more complex than tweaking a map on a FI'd bike. Not too bad to ballpark, but nailing to perfection is no small feat. And of course that perfection is only maintained as long as the intake air density remains a constant.

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post #5 of 19 Old 11-01-2010, 11:48 AM
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I vote Fuel Injection. Loading a power commander/ECU map is a lot easier than shimming jet needles and mess. I won't buy another carb'ed bike.

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post #6 of 19 Old 11-01-2010, 12:09 PM
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Fuel Injection. Duh, why do you think motogp bikes don't have carb's? Or any modern car? Carbs were a brilliant idea, but are archaic today. (plus I can't figure them out)

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post #7 of 19 Old 11-01-2010, 01:51 PM
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carbs definitely have their place, and a PROPERLY setup carb does a damn good job. That being said, FI is the way to go, and IMO a closed loop FI (919 has an open loop, no 02 sensor, it does the job but it would be better with an o2 sensor)

Theres also things like the leak jet, accelerator pump nozzle size, and direction and AP timing on a carb that will definitely play a big roll in big throttle inputs on a carb.

I personally wont ever buy a bike with multiple carbs unless its a project bike that i get for cheap... the jetting of a single carb alone on my CRF250X has taken years to get spot on... i cant imagine multiple!

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post #8 of 19 Old 11-01-2010, 02:16 PM
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While I own three carb bikes and one FI, I definitely like FI. When I had the Superhawk at blue Ridge Parkway it didn't want to run worth a crap up a high altitudes. The 9er has never had a problem with altitude.

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post #9 of 19 Old 11-01-2010, 02:49 PM
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Quote:
Originally Posted by HondaJim View Post
While I own three carb bikes and one FI, I definitely like FI. When I had the Superhawk at blue Ridge Parkway it didn't want to run worth a crap up a high altitudes. The 9er has never had a problem with altitude.
ya... other than the inherent lack of power at altitude... when i rode hwy 2 this summer which peaks at like 8200ft she never missed a step....

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post #10 of 19 Old 11-01-2010, 04:21 PM
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FI please.

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post #11 of 19 Old 11-01-2010, 05:44 PM
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I sure enjoyed my short stayed carbed CBR 9. SMOOTH as silk with no dreaded FI fuel cut. Yep, FI is the way to go. Just being able to tune with a laptop is worth its weight in gold. I will never say I'll never get another bike with a bank carbs though...

That'll work........
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post #12 of 19 Old 11-01-2010, 07:05 PM
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I can attribute the only time i have ever been down to the differences between carb'd bikes and FI'd bikes. Went from only a brief stay on a Honda Hawk GT to riding my 919 for the first time. I'm sorry to say that the on/off throttle input really got the best of me and resulted in a 5 mph layover.

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post #13 of 19 Old 11-01-2010, 07:27 PM
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This summer I was at my brother-in-laws house. The guy who bought my 99 CBR600F4. I took it for a spin since I hadn't been on her for a couple years. Gotta say, I don't miss waiting in the driveway for the engine to warm up one bit. Out on the road, it just seemed, well, lazy. FI just goes when you give it the goods. I don't know, maybe it needs some carb work I would agree though that carbs do have personality.

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post #14 of 19 Old 11-02-2010, 03:04 AM
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Do you guys have any issuies with fuels with E10-additive on carb'd bikes? Seems like there are less and less choices on our side of the world for non-E10 fuels.

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post #15 of 19 Old 11-02-2010, 05:22 AM
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Quote:
Originally Posted by honda ng gingsa View Post
Do you guys have any issuies with fuels with E10-additive on carb'd bikes? Seems like there are less and less choices on our side of the world for non-E10 fuels.

Here in Minnesota they are bending us over with that horseshit. The state mandated E10 a few years ago and is trying to mandate E20 by 2013. My FI bike runs fine as does my car, but the mileage is lower. My boat on the other hand is a 60HP 2 stroke carbed triple and it runs like ass on this stuff. When I go to Wisconsin, I can get non-ethanol premium and the motor runs like a champ. I fill it here and it has trouble starting and won't idle at all. I can't imagine what it's going to do trying to choke down E20. It's basically a big FUCK YOU from the state to everyone with small motors as most engines, including cars are not certified to run it. If the EPA says the state can mandate it and it kills one of your motors, say your lawn mower, the manufacturer is going to tell you tough luck buddy. But the idiots pushing this don't care since it makes them look good to all the enviroholes. Ethanol is all BS anyway. With the decreased mileage and all the oil it takes to produce, were not saving anything. They call it a "green" fuel. Yeah, well so is gangrene


Sorry, rant over

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post #16 of 19 Old 11-02-2010, 10:27 AM
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If it destroys your mower/car/boat then you get to go out & buy one of their government designed "green" ones instead is the way they see it.

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post #17 of 19 Old 11-02-2010, 11:48 AM Thread Starter
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I have 3 FI-ed bikes. (I buy cheap used stuff in the fall of the year). And FI is really the way to go because they, even tho there is more room for "disaster", they're probably as trouble free as carbs.

I like having one carburated street bike. I guess it's the "throw back" thing. They have a different personality. I don't let my 599 sit and warm up. I just ride with the choke on for a bit.

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post #18 of 19 Old 11-02-2010, 04:21 PM
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Quote:
Originally Posted by Sniper View Post
I have 3 FI-ed bikes. (I buy cheap used stuff in the fall of the year). And FI is really the way to go because they, even tho there is more room for "disaster", they're probably as trouble free as carbs.

I like having one carburated street bike. I guess it's the "throw back" thing. They have a different personality. I don't let my 599 sit and warm up. I just ride with the choke on for a bit.
You just can not beat carbs.
For example, my 71 Norton with straight 50 oil and a broken kick starter.
On cool nights (40s in F) after the afternoon shift was over, it would be the ritual of "just so tickling" "just so choke" "just so throttle opening" "just so "drop clutch" and "just so hit the seat". Get any one thing just a wee bit off, and you'd get a turn of the crank, a nice flooding, and a rear wheel skid. Carbs allowed the security guards to take bets on whether it would be first time run and bump night, or another hilarious evening of watching "the kid" wear himself out trying to get a run and bump start. So, you see, carbs are more flexible. FI simply is not capable of such antics. You can only push the button, get a start, and get an idle. Gosh, why have that when you can have, well, such grief ? At the END of an afternoon shift at that !

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post #19 of 19 Old 11-02-2010, 08:12 PM
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Having dealt with carbureted motorcycles for the first 50 years of my riding, and having to deal with the niggles and glitches carbs love to throw at you, I can say with considerable conviction that I much prefer fuel injection, and not just because of the considerable training I've gotten on the ins and outs of typical FI systems. Primarily I love the accuracy of the throttle, yes even the "sudden" off idle response, the bulletproof nature of the average system, and the automatic compensation for altitude, relative humidity, fuel quality, and the myriad other factors that give carbs fits.

Don't get me wrong, I have worked on carbs for four decades and have them down to an instinctual science, but given their predeliction to gumming up during storage and the effect of even a small change in altitude on not only running well, but running at all they are not optimal. CV carbs are much better in this respect -- as an example of this I rode my '72 BSA Gold Star from Estes park to Granby on Hwy 34 (Trail Ridge Road), and at the >12,000' summit it would produce a passing hiccup of power while chuffing practically pure carbon out of the exhaust, forward progress required WFO at all times, and forget about starting it at that altitude. Fast forward to 1990 and the same pass on my '88 Hawk -- while it was obviously down on power there were no other signs of distress, and starting was just as easy as at sea level. Great road BTW.

Rob

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