The issues of fuel injectors and "adventure" bikes

[Warin]

Originally Posted by PeterW

Agreed, something like the Dakar is the extreme end, most of the problems have been fuel pumps though, not the actual FI. If you are going to have five fuel tanks, the complexity of moving fuel around is likely to screw you up, carbs OR FI.
Pete

If you have 5 fuel tanks you are going to have fuel pumps, EFI or carby!

EFI fuel pumps use the fuel flowing through them to cool themselves, they are about 60 watts (when running all the time) so need some cooling. Some EFI pumps are mounted outside the fuel tank and are about the same size as the ones mounted inside the fuel tank! So it is the fuel inside the pump that does most of the cooling (given air has less cooling effect). More modern systems don't run the pump flat out all the time thus reducing the heat (and electrical) load. EFI pumps are fairly reliable, more so than the carby fuel pumps usually fitted to some bikes ... If I had a bike with a carby fuel pump I'd be servicing it every other time I'd change spark plugs.

[ttpete]

I changed a lot of pumps on pickups with two tanks. They wouldn't switch tanks until one ran dry, and that killed the pumps.

[Aussijussi]

I wonder if the KTM have FI sorted out on the new 1190ADV, getting rid of the unsteady running that occurs around 4000rpm, other than that, i've had no FI foes on my 990 adv, in the six years that i've had it.

[hugemoth]

I do a lot of off road riding alone in remote locations so it's defiantly carbs for me. I'm a mechanic. I do understand fuel injection systems, I do understand carbs. I like a simple carbed bike that will run without a battery.

[abhibeckert]

Originally Posted by Mambo Dave

Granted, this is coming from racing, but the issues that James West (and others?) had with clogged fuel injectors (KTM bike) in the current Dakar terrain (by only stage 5), and his explaining of it not being particularly a quick thing to have to change out an injector, has me questioning the need for, or role of, fuel injection

Conditions at dakar are a lot harsher than anything a typical adventure rider would face. I dunno about you, but I find riding in someone's dust cloud even more stupid than riding at night. Especially since (at least where I live) you are likely to see cattle or horses and definitely kangaroos on any dirt road. I've had a few near death experiences even when I can see clearly.

Long before there's enough dust to get through the fuel cap breather hose into the fuel (how else does it get into the injector?), I'm gonna pull over and wait until the dust clears.

Originally Posted by Mambo Dave

So if total HP isn't a huge factor in adventure riding, where instead actually making it to a destination can be close to a life or death factor, why would I want fuel injectors again?

If an engine failure is "close to a life or death factor" then you're doing something wrong. There is a long list of parts that can fail, no amount of precautions can guarantee you are going to get where you're going.

The biggest benefit for me is fuel efficiency. My 645cc fuel injected thumper is slightly more economical than the 250cc carb'd thumper it replaced, and a *lot* more fuel efficient than my dad's 650cc carb'd bike. My fuel tank is a lot lighter than his and I get further on a tank. Plus I have ~30% more power according to the dyno charts I've seen (obviously that's not because of the injector... but it is impressive when you compare fuel efficiency, especially since his transalp has fairing and my 690E does not).

I'm not fussed about what's probably a negligible power gain, but the extra fuel range and smaller tank really is a big deal. I could fit a carb if I wanted, but I choose not to. Perhaps riding in a country with dodgy fuel I might change my mind.

I'm approaching 50,000km now and have had no fuel issues, except one time when a badly routed fuel hose started leaking after rubbing on a bolt (good old electrical tape got me home).

[DepthFinder]

Originally Posted by fast4d

most newer EFI systems run 'returnless'. there's no circulation of fuel

I would think the returnless pumps are cycled and don't run constantly on the same intensity therefore eliminating overheat conditions.

Returnless simply means that the regulator is at or in the pump assembly. These systems will run a set pressure and modulate the IDC to account for changes in manifold pressure. I've never seen a pump that cycles (although many autos use voltage modulation to the pump to keep it quiet at low load and prevent regulator overrun at low IDC)

edit to add: There are also semi-returnless designs (such as BMW auto) where the fixed pressure regulator is contained in the external fuel filter with output to the engine and return from filter to tank.

[fast4d]

Originally Posted by DepthFinder

: There are also semi-returnless designs (such as BMW auto) where the fixed pressure regulator is contained in the external fuel filter with output to the engine and return from filter to tank.

that explains the $100 fuel filter I bought.

[ADW]

Originally Posted by hugemoth

I do a lot of off road riding alone in remote locations so it's defiantly carbs for me. I'm a mechanic. I do understand fuel injection systems, I do understand carbs. I like a simple carbed bike that will run without a battery.

Yep. Like my buddy's F800GS last year that the battery died and, guess what, no power = no EFI. Dead on the road. The other two of us on the trip rode 1.5 hours to the nearest town that luckily had a NAPA store with a battery close enough to fit the GS.

This experience was quite unlike my other buddy's KLR that we bump started and continued to ride when his battery wouldn't restart him on the road on a different trip.

Carbs are easy to clean in the field, and require no computer or battery power to operate. Both EFI and carbs don't like dirt, but since I don't need electricity to run my carb, that's 50% less failure mode to worry about. Better for bad conditions in my opinion. I recognize the power and fuel economy advantages of FI, but the simplicity and ability to deal with it on the side of the trail drove me to pick a carbureted ADV bike.

[bobnoxious67]

Originally Posted by fast4d

most newer EFI systems run 'returnless'. there's no circulation of fuel

I would think the returnless pumps are cycled and don't run constantly on the same intensity therefore eliminating overheat conditions.

Originally Posted by VxZeroKnots

At least on the Husky I have this is true.

Nope. "returnless" just means the fuel pressure regulator is in the tank...there is constant circulation, but it's inside the tank.

DepthFinder has it right

Originally Posted by DepthFinder

Returnless simply means that the regulator is at or in the pump assembly. These systems will run a set pressure and modulate the IDC to account for changes in manifold pressure. I've never seen a pump that cycles (although many autos use voltage modulation to the pump to keep it quiet at low load and prevent regulator overrun at low IDC)

edit to add: There are also semi-returnless designs (such as BMW auto) where the fixed pressure regulator is contained in the external fuel filter with output to the engine and return from filter to tank.

[Tepi]

Unless you have magneto ignition on your bike, you're going to need power/battery for ignition. Therefor carbed bikes WILL need a source of power, so if your magneto/alternator dies and your battery runs out, you're still shit out of luck. Might wanna find a diesel bike, they should basically run without power if you get them started.

[hugemoth]

My little dual sport bike doesn't even have a battery. Lights and everything run off the alternator. The CDI ignition module went out once but I carry a spare. My other dual sport has a battery to run the electric starter and power the turn signals, but it also has a kick starter and will run and the rest of the lights will work without the battery. I carry a spare CDI on that one too.

Originally Posted by Tepi

Unless you have magneto ignition on your bike, you're going to need power/battery for ignition. Therefor carbed bikes WILL need a source of power, so if your magneto/alternator dies and your battery runs out, you're still shit out of luck. Might wanna find a diesel bike, they should basically run without power if you get them started.

[Tepi]

Right, its running off the alternator. You could do that with any bike, just pushstart it, its not the first time someones started a fuel injected bike with a dead battery, can be done with cars too. Often the battery dies with sufficient voltage to drive the EFI system, but you wont have enough juice to use the starter.

I'm just saying if you have a battery/alternator fault in the middle of nowhere, least of your worries is the EFI. Its not really the biggest concern for me. EFI has been around for over 20 years, suffice to say its pretty much reliable. Carbs can also break down and if you're in the middle of nowhere fueling up at a shoddy place or rain water seeps in through the cap, water can cause serious running problems on carbs, not so much with EFI. Floats can crack or ingest fuel which would cause issues, you can crack the diaphragm on constant velocity carbs, you can bend/wear out a needle, you can have an O-ring break. All of those would need spare parts.

Even if your battery dies, your alternator will still work and if you arent an asshole, you can probably ask someone to jumpstart your EFI bike.

[PeterW]

I have bump started a DL 650 (FI) on the flat.

I'll admit, the effort damn near killed me, but it did start and ran well once started. (Next stop "Battery World")

Pete

[VxZeroKnots]

Originally Posted by bobnoxious67

Nope. "returnless" just means the fuel pressure regulator is in the tank...there is constant circulation, but it's inside the tank.

DepthFinder has it right

Good to know, the extent of my knowledge was there is only one hose going to the injector. As opposed to my truck that has hoses and wires and shit going everywhere. Out of sight out of mind

[Davidc83]

Originally Posted by Tepi

Unless you have magneto ignition on your bike, you're going to need power/battery for ignition. Therefor carbed bikes WILL need a source of power, so if your magneto/alternator dies and your battery runs out, you're still shit out of luck. Might wanna find a diesel bike, they should basically run without power if you get them started.

This all depends on what bike and manufacturer. I had a 2006 Suzuki gz250 which had a carb. I left the key on (lights on) by hitting the kill switch once instead of turning bike off with the key. I was gone 1.5 hours, it drained the battery, and the bike would not start, even with a bump start (got the bike up to 25mph, 2nd gear down hill, and nothing); bike required a battery for ignition. Just because you got a carb, doesnt mean you can bump start with dead or no battery. I test all my bikes at what speed, which gear, would be best to bump start if the starter fails. I still have one carb bike (klx250sf-which also doesnt bump start with dead or 0 battery) and 2 FI bikes.

My question, how is the sand supposedly getting into the FI; bad air filters? sand contaminated gas (my best guess would be this one, cause sand gets into everything).