HARLEY EFI vs Carbu

[Mickey Cohen]

So Ive been riding my nighster 1200 from 2009 almost 10 months now. I love it, great upgrade from the yamaha SR but I have problems with the full injected carb. Some times it releases too much gasoline some times not enough. Apparently only Harley shop have the exact map infos and every time i retune the full injected carb it costs a lot and doesnt last long. Need to retune it again as if the card didnt save the info.

The local garage proposed to put a classic carb for 10k and all my problems will vanish. Fixing and tuning will be easier and less costly. What do you guys think?

[NeverSure]

I've had a lot of both and I'll take the EFI for ease of starting, fuel economy, overall power, easier tuneups and all. Someone doesn't know how to tune your EFI. A change in the power band and/or mixture etc. just requires a computer download which is predictable but should be double checked on a dyno. You need to enrichen the mixture if you install freer flowing parts such as exhaust, intake, cam etc. as these will lean out the mixture for carb or EFI. Carbs get rejetted.

Harley never made a good carburetor. Most didn't have an accelerator pump but rather had a power valve. Harleys aren't made for racing. From about mid 1970's until about 1988 Harley used the Keihin Butterfly carb which is junk. From about then until about 1999 when the EFI came out the carb was a Keihin CV CVK often just called the CV. It was much better but still many guys replaced them with an aftermarket such as a Mikuni carb. That's a really good carb but not cheap and you still have to have someone good to tune it.

When they tune it they need a dyno to read power and an exhaust probe to read heat and mixture results. Too lean and an engine can overheat and get severe damage. Incoming, evaporating fuel is very cooling almost to the point of being refrigerating and in some cases and climates can literally cause carb ice.

I tell you all of this simply to explain that you couldn't run fast enough to give me another Harley carb, especially if no one knows how to tune it. I always immediately bought a Mikuni and had it dyno tuned by an expert until EFI came out in '99.

This is the issue. Someone has to first tune everything. The factory tunes the EFI which should be left alone because it has no moving parts and just needs a couple of plugs once in a while. That's unless it simply needs a download to enrichen the mixture and that's a one shot deal after any major change.

Someone doesn't know and/or doesn't have the tools to do a simple setting on your EFI as it should be incredibly stable and dependable.

Cheers.

Edited July 3, 2015 by NeverSure

[NeverSure]

May I please rant some more about Harleys? OK, thanks, LOL.

Harleys are designed to develop gobs of torque at low RPM and pull two people and luggage over US mountains. They are torque monsters at lower rpm's and don't even have a high rpm function. Low rpm's in a car or motorcycle are nice for cruising all day. We like 5 speed overdrive for cruising and so does the Harley, needing 4th gear only for the steepest mountains.

The Harley sound is unique and patented. The sound is copyrighted and that doesn't expire. A couple of Japanese firms tried to mimic the design and sound and got shut down. The Harley has a single pin crank which fires both cylinders on the same revolution and then loafs for a complete revolution. That's the unique sound we hear which almost sounds like the engine is misfiring at an idle. At speed it smooths out. Other multi-cylinder engines have multiple crank bosses (where the big end of a rod attaches) that are offset to allow 180 degree firing to smooth out the engine.

Don't worry if your Harley sounds like it's still trying to start when it's idling, 555. It's just fine. That engine will run for 100,000 miles/160.000 kms or more between overhauls. They may be clunky, but they are tough. Chain a Harley back to back with a high horsepower sport bike and the Harley will skid the tires off the sport bike by the time it gets to 1500 rpm. It has a different design and purpose than does a sport bike and both are great bikes.

Cheers

Edited July 3, 2015 by NeverSure

[Mickey Cohen]

2 diffrent guys have tunes de EFI including V powe (Harley official dealer in rama 9) the carb just went wrong a few days after.

May the ECU be damaged?

My local garage told me I could either change to new EFI for 35k or carb (mikuni, or harley) for 10k

[guzzi850m2]

I ran a Mikuni on my 2002 Road King and it ran very good.

No FI on it but I would have preferred a FI HD as EFI is the way to go in the long run.

What EFI are you running now? Original? There are many no HD EFI out there, PowerComander and so on.

Some EFI's can more or less tune themselves depending on riding style and set-up but off-course there is a map loaded in it, suited for the bike.

Have you tried some of the shops in Pattaya? There are 3-4 HD shops here and they can give you advice.

Sadly one of the best EFI tuners are not here anymore, a British guy that had 100's of maps on his PC and would load them on your bike for very small money.

[NeverSure]

I don't know what to say. If the guy doesn't know how, or doesn't have the equipment to check things... The Electronic Control Unit (ECU, computer) reads the crankshaft position ,air temperature, engine temperature, throttle position, manifold pressure, RPM, etc. and makes necessary adjustments before fuel is sprayed in exact amounts at exact times into the engine to become a vapor mixed with air/oxygen. If any of that goes bad an electronic diagnostic will quickly inform on it so it can be replaced. The engine can do that and give a readout by the speedometer. There's also a diagnostic machine that can tell more. Replacing any part such as a sensor is easy and not too expensive if they get it right the first time. The only thing that's really expensive is the control module which is the computer. I've never seen a control module go bad but then... Who knows.

If it went bad on me right after they worked on it I'd wonder...

If you knew for certain that these people could swap on a carb and your troubles would be over, that would be one thing. I don't know at all if they can set up a carburetor either. I've never really worked on my own because I know a couple of fabulous mechanics in the US who can make one of those things dance.

???

Cheers

[thrilled]

My last Harley I could have got fuel injected.I went with the carb instead.I then took it off and put on A S&S super E.

Got it rejetted and it works great.If you do engine work you'll want to go with the G.

[thaiguzzi]

May I please rant some more about Harleys? OK, thanks, LOL.

Harleys are designed to develop gobs of torque at low RPM and pull two people and luggage over US mountains. They are torque monsters at lower rpm's and don't even have a high rpm function. Low rpm's in a car or motorcycle are nice for cruising all day. We like 5 speed overdrive for cruising and so does the Harley, needing 4th gear only for the steepest mountains.

The Harley sound is unique and patented. The sound is copyrighted and that doesn't expire. A couple of Japanese firms tried to mimic the design and sound and got shut down. The Harley has a single pin crank which fires both cylinders on the same revolution and then loafs for a complete revolution. That's the unique sound we hear which almost sounds like the engine is misfiring at an idle. At speed it smooths out. Other multi-cylinder engines have multiple crank bosses (where the big end of a rod attaches) that are offset to allow 180 degree firing to smooth out the engine.

Don't worry if your Harley sounds like it's still trying to start when it's idling, 555. It's just fine. That engine will run for 100,000 miles/160.000 kms or more between overhauls. They may be clunky, but they are tough. Chain a Harley back to back with a high horsepower sport bike and the Harley will skid the tires off the sport bike by the time it gets to 1500 rpm. It has a different design and purpose than does a sport bike and both are great bikes.

Cheers

# Re, the above points. Just about every v twin ever made has a single crank pin just like HD, but rods run side by side, and hence cylinders are offset. The difference, and hence the noise is a) the firing interval, and the angle between the cylinders, most v twins being 90 degrees, some 60, and the famous Vincent 55, Harley being 45 degrees, This, along with the firing interval gives you the "famous patented" HD noize. potato, potato...

# FI needs somebody who knows what they are doing with the software and computer, and preferably a dyno.

# That is why i dislike FI. Being a Luddite, and having a phobia of all things modern in technology it's a carb every time.

# Having worked as a m/c mechanic and machinist my whole life, i also never let another shop work on my bike. Hence i don't have FI.

# To the OP, you gotta find someone who is genuinely knowledgable with FI, not anybody, but somebody goooood.... Or throw it in the bin and fit a carb...

[Mickey Cohen]

I switched to a carb...i love it. More control more precision and prediction in the acceleration I dont know why.

Not as fast on 0 to acceleration tho. Can I fix that?

How about the idle? If its low I go slower right?

[guzzi850m2]

I switched to a carb...i love it. More control more precision and prediction in the acceleration I dont know why.

Not as fast on 0 to acceleration tho. Can I fix that?

How about the idle? If its low I go slower right?

A re-jetting should solve the acceleration, BUT make sure the mechanic knows what he does.

When I had my Mukuni fitted it took him 2 days to get it right (he didn't have a dyno), but this Australian guy knew what he was doing all right.

No don't let it idle to low (My Aus. Mec. told me), you risk the lub oil pressure gets too low and damage the engine.

It should say in the manual what the idle speed is, don't go below recommended.

Edited July 10, 2015 by guzzi850m2

[Mickey Cohen]

I switched to a carb...i love it. More control more precision and prediction in the acceleration I dont know why.

Not as fast on 0 to acceleration tho. Can I fix that?

How about the idle? If its low I go slower right?

A re-jetting should solve the acceleration, BUT make sure the mechanic knows what he does.

When I had my Mukuni fitted it took him 2 days to get it right (he didn't have a dyno), but this Australian guy knew what he was doing all right.

No don't let it idle to low (My Aus. Mec. told me), you risk the lub oil pressure gets too low and damage the engine.

It should say in the manual what the idle speed is, don't go below recommended.

Thanks

What is re jetting in thai?

Now the bike bike fires. The mecanic told me he would fix it when i go back. Is that linked to re jetting?

[andreandre]

I switched to a carb...i love it. More control more precision and prediction in the acceleration I dont know why.

Not as fast on 0 to acceleration tho. Can I fix that?

How about the idle? If its low I go slower right?

How about the idle? If its low I go slower right?

Not sure what you mean here..care to elaborate..

[Mickey Cohen]

I switched to a carb...i love it. More control more precision and prediction in the acceleration I dont know why.

Not as fast on 0 to acceleration tho. Can I fix that?

How about the idle? If its low I go slower right?

A re-jetting should solve the acceleration, BUT make sure the mechanic knows what he does.

When I had my Mukuni fitted it took him 2 days to get it right (he didn't have a dyno), but this Australian guy knew what he was doing all right.

No don't let it idle to low (My Aus. Mec. told me), you risk the lub oil pressure gets too low and damage the engine.

It should say in the manual what the idle speed is, don't go below recommended.

Thanks

What is re jetting in thai?

Now the bike bike fires. The mecanic told me he would fix it when i go back. Is that linked to re jetting?

I meant back fires!

Why do people like low idle? Only for the sound?