The issues of fuel injectors and "adventure" bikes

[eatpasta]

Originally Posted by DAKEZ

My Adventure bike is carbureted. Gravity never breaks.

I think anyone on this board would agree with you on that, but its got nothing to do with fuel....

[GoUglyEarly]

Originally Posted by corndog67

Move into the 21st century, because they are not going back to carbs, no matter how much you 7 or 8 guys cry about it.

My '99 XR400 is plated and NJ-street legal.

My buddy's 21st century XR400 is persona non grata at le DMV.

The 21st century sucks. Too many laws

[Ragin Rabbi]

I thought there was a difference between a Rally Bike and an Adventure Bike. But what do I know.

[JimVonBaden]

Originally Posted by larryboy

Racing has nothing to do with it, Jim. Where and how a person rides...empty lonely places of the west, alone...give me a carburator over FI any day of the week.

Racing was the subject, I responded to it!

However, injection is no more likely to fail than a carb, and IMHO less so!

Jim

[Warin]

EFI vs Carbs...

While you can get the same max power from both systems, the EFI will be more efficient over the entire range of operating conditions compared to a single carb set up (read singe set up for multiple carbs if that is required). Efficient here means fuel used over the distance traveled.

Why do racers then prefer EFI? Because they can carry less fuel = less weight ... And they start better and run better over the entire rev/load range.

Any delay in racing is seen as a bad thing. A blocked carby would be seen in the same light as a blocked injector. A well trained person faced with either situation would be able to 'fix' it in similar times. In fact a EFI system can be faster due if well designed for fast servicing (eg the injector can be set up to be removed without removing anything else.
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The 'problem' with EFI is there is a lack of general knowledge by the backyard mechanic and the general public. That will change over time. The backyard mechanic will either learn or die off.

[slartidbartfast]

This is the second time in recent weeks I have heard that carbs are preferred by KTM in the Dakar rally because of fuel problems. I find it strange as I would expect that any entrant who has the funding and abilities to compete in the Dakar would easily be able to ensure they were filling up with clean gas. Still, if that is really a problem I'm not sure that changing an external fuel filter or an injector would take very long if they were designed for quick changing. I suspect there may be another reason that KTM doesn't want us to know about and fuel cleanliness is just the excuse. Maybe their fuel pumps burn up when fuel is sloshing back and forth for hours on end introducing bubbles ... IDK

For an adventure bike both systems have their merits. A carburetor is undoubtedly easier to work on by the side of the road and arguably has fewer parts to fail. I suppose you could carry a complete spare carb with you, quite easily if you wanted to. However, modern FI systems are extremely reliable, deal with large temperature and altitude differences more effectively and can still be serviced and maintained fairly easily by someone who knows what they are doing. Furthermore, you are likely to get better fuel efficiency from FI and I for one, would trade the few extra miles per tank for any theoretical shade-tree wrenching advantages. I have never had any trouble from the FI systems on my current so-equipped bikes but can think of several times when carbureted systems have had problems of one sort or another (fuel leaks, stalling, poor running, etc. - even leading to a holed piston one time.) This has especially been the case when a bike has sat unused for any length of time.

I really don't understand the strong opinions held by some people on this topic. I'm not going to let the fuel delivery system on a bike influence my choice of purchase (unless that particular implementation has a known issue) and I'm not going to sweat about whatever the manufacturer has seen fit to install. If I take my DR350 up into the Rockies to ride some of the high passes (which I hope to do some day), I suppose I will revert to the CV carb and/or take a supply of jets with me. That might be a small hassle but the bike is old, cheap and will run without a battery if necessary so it's a reasonable trade-off (yes I know there are some battery-less FI bikes now.)

[larryboy]

Originally Posted by JimVonBaden

Racing was the subject, I responded to it!

However, injection is no more likely to fail than a carb, and IMHO less so!

Jim

Oh, I thought the title of the thread was "adventure bikes"...I must have missed the hijack.

I've never even heard of a failed carb. Failed fuel pumps, clogged screens and stuck injectors, fubar'd TPS', yes.

[Jnich77]

Originally Posted by JimVonBaden

If you are not racing it isn't an issue. You can cary a spare, or clean it along the way. Knowing what you are doing is the key factor for a traveler.

Jim

Exactly!!!! Not like they take up a lot of room....lol.

[PeterW]

I've had more problems with carbs that FI in all the bikes I've owned, including dirt in the jets. Far less tolerant of water as well - so far the FI has been faultless.

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

[syaufu]

Rode London to Bejing..Injected bike..bad fuel ..17,000 ft ..no problems...Lady with Carbed bike..in van above 14000 ft and worked on carb and jets almost every nite when in the high altitude of Tibet trying to get bike to run properly...not a mechanic..just a rider but I will take an injected bike any day after that experience..bj

[ttpete]

Originally Posted by syaufu

Rode London to Bejing..Injected bike..bad fuel ..17,000 ft ..no problems...Lady with Carbed bike..in van above 14000 ft and worked on carb and jets almost every nite when in the high altitude of Tibet trying to get bike to run properly...not a mechanic..just a rider but I will take an injected bike any day after that experience..bj

In-tank pumps will live a long time as long as the fuel level is kept up. The pump depends on fuel to cool and lubricate it, and low fuel levels will kill it in short order.

[JimVonBaden]

Originally Posted by ttpete

In-tank pumps will live a long time as long as the fuel level is kept up. The pump depends on fuel to cool and lubricate it, and low fuel levels will kill it in short order.

That's a bit of a stretch. Though fuel does cool the pump, running low on fuel will not cause a pump to fail in "short order"! The cooling comes from fuel going through it far more than around it.

Jim

[ttpete]

Originally Posted by JimVonBaden

That's a bit of a stretch. Though fuel does cool the pump, running low on fuel will not cause a pump to fail in "short order"! The cooling comes from fuel going through it far more than around it.

Jim

Bear in mind that fuel is continuously recirculated through the pressure regulator, and that last pint can get pretty warm. Even though the pump section may be cooled, if there's a deep enough sump the motor bearings can run without fuel to lubricate them once the level drops enough.

[fast4d]

Originally Posted by ttpete

Bear in mind that fuel is continuously recirculated through the pressure regulator, and that last pint can get pretty warm. Even though the pump section may be cooled, if there's a deep enough sump the motor bearings can run without fuel to lubricate them once the level drops enough.

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.

[VxZeroKnots]

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.

At least on the Husky I have this is true.