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-   -   Carb vs. EFI (http://www.horizonsunlimited.com/hubb/which-bike/carb-vs-efi-56238)

Uhuru 22 Mar 2011 21:20

Carb vs. EFI
 
I love riding in the mountains in Colorado, where I live. One ride I like in particular starts at about 5300 ft. and goes over a 12,500 ft. pass. Almost any ride I pick will involve 15mph hairpin turns and steep climbing to get to a 10,000-11,000 ft pass.
I am planning several multi-day rides this summer, mostly on tarmac, and a 7500+ mile ride to Alaska and back in August, so I have two competing issues--ease of maintenance/repair, on one hand, and adaptability to significant altitude changes on the other hand. I'm pretty happy with this 650cc size motor as good all-around for my needs.

I ride a BMW F650GS Dakar right now (EFI), but she's a comparatively heavy, tall girl with a high C of G, which makes her a little awkward in the tight turns I see so often. I'm thinking of changing bikes, maybe to a DR650se, (more than 50# lighter and a lower C of G) but I'm wondering if I should even consider a carb'd bike because of the altitude I regularly ride. Any thoughts or guidance between these two bikes in light of these issues would be appreciated.

chris 22 Mar 2011 22:16

Hi Uhuru
I have no particular opinion on the topic. All the bikes I own have carbs, but that's more to do with me being cheap and riding old bikes, rather than not liking (more modern) efi. If you put

site:www.horizonsunlimited.com efi carbs

into a google search box you get lots of threads where this topic has been discussed already. Maybe there is some useful advice there?

cheers
Chris

*Touring Ted* 22 Mar 2011 22:37

Modern EFI is fantastic !!

It deals with altitude really well and the ecomony vs carbs is brilliant..

It used the be that EFI was snatchy while a nicely tuned carb was smooth but it's near impossible to tell these days.

The only downsides to efi is the extra electronics involved but it doesn't HAVE to be so complicated and is VERY reliable in modern bikes.

The "man down the pub" will always say "im never riding one of those FI bikes with all that stuff to go wrong"... Well, have you ever seen inside a CV Carb ?? All those springs, jets, needles, valves and diaphrams.


Anyway, back to the altitude issue... It's not like a carbed bike won't run or break down at that change in height.. You may not even notice it !

T.REX63 22 Mar 2011 22:45

EFI has my vote any day. As mentioned by Ted, today's electronic is bullet proof.



P.S.: :welcome: to the HUBB!

TurboCharger 22 Mar 2011 22:56

Quote:

Originally Posted by T.REX63 (Post 329344)
EFI has my vote any day. As mentioned by Ted, today's electronic is bullet proof.



P.S.: :welcome: to the HUBB!


+1 for EFI

+2 for :welcome: to the HUBB

Dodger 23 Mar 2011 01:19

It all depends which bike for EFI --my VStrom is not smooth at low rpm.
You are not going to get any more power out of the bike by using EFI just more convenience .If you don't like rejetting then steer clear of carbs .

Uhuru 23 Mar 2011 02:05

Thanks
 
I appreciate the guidance from everyone. Thank you. I did check other threads but didn't see one about the altitude issue. These replies are very helpful.

colebatch 23 Mar 2011 04:03

FI is the go.

Diesel submarines, Piston engine aircraft etc all run fuel injection. Far more mission critical equipment than adventure motorcycles run fuel injection. Its been around since 1925 and widespread in many applications since the second world war. Its not some new fangled technology. Even Electronic FI has been around for 50 years.

They havent sold a car with carbs in the US since 1992 ... if anyone thinks 1970s carbed cars have more reliable induction than modern EFI cars, they are living in a dream.

EFI all the way. ON top of it all, a fuel injector is actually a far more simple piece of kit than a carb. There is effectively only one moving part in the injector.

I think the need to use carbs is one of the great adventure motorcycling wives tales.

Uhuru 23 Mar 2011 04:48

Thanks
 
Thanks, colebatch. Very helpful. People keep writing how easy carbs are to work on compared to EFI, but others point out EFI is more efficient and more reliable.
Now, get some sleep! By my watch it looks like it was about 4:00 a.m. in UK when you wrote this!

colebatch 23 Mar 2011 04:59

Quote:

Originally Posted by Uhuru (Post 329377)
By my watch it looks like it was about 4:00 a.m. in UK when you wrote this!

That may be so, but I am in Canada right now :)

Dodger 23 Mar 2011 05:29

" if anyone thinks 1970s carbed cars have more reliable induction than modern EFI cars, "

Well I have to differ , I have a Dodge Ramcharger with an EFI system that is very unreliable and drinks fuel much more than my friend's carbed version .
I am waiting to find a good carb unit to put in it .Principly because a carb is a mechanical device that I can see with my own eyes ,fix with simple tools .
When they are new both systems are reliable but when they get old ,well a new or rebuilt carb cures most ills .You can hunt for ever for that frayed wire,, or cracked piece of plastic on an EFI system .
I don't have any preference one way or the other on a bike but I know that a gravity fed carb is more fixable and therefore ,in the long term, more reliable for a stone age mechanic like myself .

Another thing you have to consider is the engine characteristics ,many bikes run very lean to get around emissions tests .VStroms have a notorious weak spot at around 3500 rpm .Now to fix that you have to get the computer remapped with a power commander and that costs about $300 .If the bike had carbs ,all I would have to do is raise the needles to richen up the mixture and that costs nothing but my time .

TurboCharger 23 Mar 2011 09:47

Quote:

Originally Posted by Uhuru (Post 329366)
I did check other threads but didn't see one about the altitude issue.

:confused1: :confused1: Seriously?

Let me google that for you

Don't use the HUBB search, it doesn't work (well).

:euro: Dear chap there are 4,370 such topics.

*Touring Ted* 23 Mar 2011 12:43

Quote:

Originally Posted by colebatch (Post 329371)
EFI all the way. ON top of it all, a fuel injector is actually a far more simple piece of kit than a carb. There is effectively only one moving part in the injector.

I think the need to use carbs is one of the great adventure motorcycling wives tales.

Absolutely... If only some of the major manufactures would put a decent, reliable fuel pump in their bikes to compliment it as the FI is so reliant on this.



Quote:

Originally Posted by Dodger (Post 329381)
" if anyone thinks 1970s carbed cars have more reliable induction than modern EFI cars, "

Well I have to differ , I have a Dodge Ramcharger with an EFI system that is very unreliable and drinks fuel much more than my friend's carbed version .
I am waiting to find a good carb unit to put in it .Principly because a carb is a mechanical device that I can see with my own eyes ,fix with simple tools .
When they are new both systems are reliable but when they get old ,well a new or rebuilt carb cures most ills .You can hunt for ever for that frayed wire,, or cracked piece of plastic on an EFI system .
I don't have any preference one way or the other on a bike but I know that a gravity fed carb is more fixable and therefore ,in the long term, more reliable for a stone age mechanic like myself .

Another thing you have to consider is the engine characteristics ,many bikes run very lean to get around emissions tests .VStroms have a notorious weak spot at around 3500 rpm .Now to fix that you have to get the computer remapped with a power commander and that costs about $300 .If the bike had carbs ,all I would have to do is raise the needles to richen up the mixture and that costs nothing but my time .

You can get good and bad FI as you know. Depends how much R&D they manufacturer can be bothered putting into the mapping.

Carbs are still WAY easier for the home mechanic to tune and fettle with and probably why they are still standard kit accross the board on MX/Enduro bikes..Although, expect that to change very soon. I think Honda are making their whole CR series FI this or next year !!

Blimey !!

pecha72 23 Mar 2011 13:15

Quote:

Originally Posted by Dodger (Post 329381)
Another thing you have to consider is the engine characteristics ,many bikes run very lean to get around emissions tests .VStroms have a notorious weak spot at around 3500 rpm .Now to fix that you have to get the computer remapped with a power commander and that costs about $300 .If the bike had carbs ,all I would have to do is raise the needles to richen up the mixture and that costs nothing but my time .

Actually you don´t, because the standard EFI box is programmable. You´ll just need to connect it to a laptop with proper software on it (this is usually done at the dealer during other maintenance) and adjust fuel amounts just a little at low rpm on partial throttle openings.

But I´m sure the dealers, who sell Power commander or similar systems would disagree, it is their business afterall!!

For me, it´s FI all the way nowadays, simple as that. I´ve had several carb´d bikes (and cars) during the years, and in FI, both functionality and dependability are just superior, even if/when planning an overland-trip to faraway countries.

Threewheelbonnie 23 Mar 2011 13:49

I don't think you can just split this carbs and FI. My MZ has one carb with maybe three seals and half a dozen moving parts. It either works or it doesn't, you can tune it with a screwdriver and a metal rule so long as you can count to 5. The pair of things on the Bonneville have dozens or O-rings, linkages, diaphragms and goodness knows what else and require vacuum gauges and some sort of surgical manipulator to tune them. The FI on the Brick is a series of components that can be tested with a multimeter.

I'd ditch the carbs on the Bonneville for FI tomorrow if I could afford the newer bike.

For those terrified of the black box: I worked for the largest manufacturer of truck ABS ECU's in the world for 12 years. I that time, in the UK, I accepted warranty claims on one ECU. I saw dozens of claims a month from dealers who were too stupid or mean to get the right diagnostic kit and had started swapping parts. I saw a few great examples from owners who couldn't read, such as the one with burn marks from the welding set earth. I once travelled 400 miles to change a fuse on a bus the dealer had fitted three ECU's to in the space of a week. There is no shortage to idiots who'll blame what they can't understand, the trick is simply not to deal with them. ECU's never ever fail when compared to plugs, other bits of wiring and petrol soaked O-rings. Given my 1984 BMW has FI, we really should be getting out of this era with FI by now.

Andy


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