Think of the Carburetor as Your Friend

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July 15, 2010 | By: J&P Cycles

Editor’s note:  Today we present the second of two blog entries about carburetors versus fuel-injection systems. Yesterday we heard Patrick Garvin discuss the wonderfulness of modern fuel injection. Today we hear from Kody Wisner, who will opine on the simple magic of a motorcycle carburetor.  Read ’em both, compare notes and come to your own conclusion — unless, of course, your mind’s already made up.

By Kody Wisner

In this era of high-tech gadgetry, the trusty carburetor is a survivor — hanging on with bloody fingernails against some very advanced fuel-injection systems. But know this: The modern carburetors of today are very different from those of yesteryear.

Adjustable accelerator pumps, advanced fuel circuits and easier adjustments are a few of the improvements that have been made to the carburetor recently.  And while it’s true that you’ve got infinite adjustments to fine-tune most modern fuel-injection systems, if you don’t know what you’re doing, it’s not going to do you any good. The same can be said for carbs, of course. If you don’t know how to tune them, they won’t be perfect. But one advantage a carb has over fuel injection is that most mechanics have worked with carbs. Far, far fewer have any experience at all with fuel-injection systems. 

Carbs are simple mechanical parts with one mission:  Supply metered fuel to your engine. Fuel-injection systems are far more complex and rely on several different sensors, as well as other electronic devices to supply the fuel. And everybody knows that electronics will let you down faster than a high school cheerleader. It’s just the way it is. But it takes a long time for a mechanical part to “wear out.” Remember the acronym KISS? That stands for “Keep It Simple Stupid.” The KISS principle says simplicity is a key goal in design, and that unnecessary complexity should be avoided. In fact, if it weren’t for the EPA and its strict emissions standards, my guess is that most bikes would still be equipped with carburetors. There should be no argument from anybody that carbs are far simpler to design, manufacture, maintain and repair. End of that story.

Having said that, I’ll admit that a closed-loop fuel-injection system is great when it comes to long-distance touring on varied terrain. But a trusty old carburetor that is properly tuned will have no issues getting you back and forth across the country. Maybe by the time you reach the top of Pikes Peak, your bike might not be running its best, but my guess is that it’ll get you back down the hill just fine.

And I agree you shouldn’t remove a fuel-injection system that’s in good working order for a carburetor. But by the same token, I know there are some fuel-injection systems out there for which there are no replacement parts, and in that situation, I’d switch back to a carb in a heartbeat. Speaking for myself, and other motorcycle purists, I’ll stick with a carburetor on my bike. Then if I do have a problem, I’ll be able to figure it out by myself. Without any help from a computer, thank you.

Comments: 13 Comments | Categorized Under: Tech Tips

Comments (13)

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[...] Th&#1110nk &#959f th&#1077 Carburetor &#1072&#1109 Y&#959&#965r Friend | Motorcycle P&#1072rt&#1109 … [...]

[...] Th&#1110nk &#959f th&#1077 Carburetor &#1072&#1109 Y&#959&#965r Friend | Motorcycle P&#1072rt&#1109 … [...]

[...] Th&#1110nk &#959f th&#1077 Carburetor &#1072&#1109 Y&#959&#965r Friend | Motorcycle P&#1072rt&#1109 … [...]

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It’s far cheaper to modify a carb bike. No high flow injectors, remapping, EPA rules after 06, wimpy sounding EPA mufflers etc. I’ll put my CV up against any aftermarket carb or FI. It does take trial and error to get it right but that’s how you get experience and I’ve done plenty of it. People are surprised at how well their bike runs after a carb massage and ignition upgrade and VOES tune with no other changes.

[...] Think of the Carburetor as Your Friend | Motorcycle Parts and Accessories Blog [...]

I’m sure these electronic wizardry marvels have plenty of advantages on the newer HD’s with all the gadgets, bells, & whistles the “new school” owners just love to brag about. I take my “91″ FLH-TP, (that I bought used in late “92″) has over 130,000 mls over any of these high $ machines. Something I have noticed over the years are the ever increasing open, enclosed, bike trailers, huge RV’s w/a trailer being towed, & 18 wheelert packed w/ these marvels to meet up with their owners who flew in to their destination. Does the 50,000 miles for the EFI includes trailer miles? I go with Kody’s ideology, “KISS”.

speaking of carbs I need a carb body and idle adjustment screw for a 1996 sporty
912-224-7417 thanks

speaking of carbs I need one for a 1996 sporty just the body and Idle adjustment screw.
912-224-7417

Harley is unique in the world of carburetors in that they were able to remain carbureted far longer than most. This was due to the CV style carburetor manufactured by Keihin. Unlike conventional carbs or those with throttle actuated slides, the CV’s variable venturi slide constantly varies the intake velocity based on vacuum and atmospheric conditions. Hence the name CV or constant velocity. Not only did the design act to self regulate under different conditions and altitudes, it’s always been a reliable carburetor to keep tuned. Even as EPA regulations forced other manufactures to move to fuel injection only, the Harley CV remained on production bikes for 18 years due to it’s efficiency. With well over 2 million carbureted Harley motorcycles sold between 1989 and 2006, the CV carburetor has left it’s mark in Harley history.

Great information! I’ve been looking for something like this for a while now. Thanks!

EFI is better thought of in the same way as ignition components rather than “vs. carb”. Granted, a carb won’t leave you on the side of the road, but an ignition module will, and carb bikes have had those for decades. The overall failure trend of today’s electronic systems is not necessarily compounded by the additional number of components. The assumption that greater complexity always equals a higher failure trend is a mis-characterization in this case, because it’s actually based on the experienced failure trends of increased mechanical complexity, and not on any experience at all with increased electronic complexity. If it was, this experience would show that the opposite is true: Many EFI bikes today run 50,000 miles and more without an electronic failure at all.

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