Fuel Injection

[sunbear]

Might be a silly question, but i was just wondering what the benefits of fuel injection are ? A lot of bike reviews seem to slag it off for being "on, off" or "bad fuelling". Why move away from good old carbs ?

Cheers
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Bikes had : BMW F650, suzuki tr50, gt125, SV400, GSXR600 SRAD. Honda CBR900RRP, CBR600FX, CBR1000F, VT600, Transalp 600, mtx125, nsr125r, CB500T, Yamaha fy50, tzr125, tdr125, XV535, Diversion 600, Fazer 600, TDM850 MK1 & MK2, Majesty 400, XV 1100. Cagiva mito evolution, Aprilia rs125, Piaggio x9 125. DNA 125 . Suzuki Bandit 600, GZ125 Marauder, RF600 , RF900RS2, Kawasaki ZZR400, ZX6R Ninja, ZZR600 . Ducati 750 Sport . Triumph Tiger 955i. CURRENT : 2004 Kawasaki Z750 and LOVIN IT !

[finpos]

Put simply, using fuel injection gives you much better control of the fuel/air ratio at any given condition. that means manufacturers can increase fuel efficiency and reduce emmissions, which is what they need to do to meet modern standards.

I think one of the best examples is what happens when you are on overrun, i.e. engine braking. Carbs always bleed a small amount of fuel through, which is usually wasted - popping an burbling. With modern fuel injection, you simply cut the fuel entirely. instant fuel and emmission saving, but might explain the on/off thing.

What they are complaining about is not that injection is worse than carbs, but the fuelling and ignition mapping they use is biased towards efficiency rather than fun. It's not "bad", it's "different"

(Remembers horrific month trying to get mechanical fuel injection system working before throwing it in the bin and fitting carbs)

finpos.

[0ddball]

I don't see why they seem to get it so bad on a bike. Apart from a few ropey years in the 80's car's have been running it fine for 20 years.

Injection, mapped properly, is better than carbs in every way, i can only assume bike manufacturers purposely map them in the way they do for good reason.

Plus i think half of the complaining is for the sake of it from older bikers who just don't like change and who remember "the good ol' days" where you could spend a Sunday afternoon greasing nipples and playing with their points.

[finpos]

[sunbear]

Thanks fellas. Very imformative
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Bikes had : BMW F650, suzuki tr50, gt125, SV400, GSXR600 SRAD. Honda CBR900RRP, CBR600FX, CBR1000F, VT600, Transalp 600, mtx125, nsr125r, CB500T, Yamaha fy50, tzr125, tdr125, XV535, Diversion 600, Fazer 600, TDM850 MK1 & MK2, Majesty 400, XV 1100. Cagiva mito evolution, Aprilia rs125, Piaggio x9 125. DNA 125 . Suzuki Bandit 600, GZ125 Marauder, RF600 , RF900RS2, Kawasaki ZZR400, ZX6R Ninja, ZZR600 . Ducati 750 Sport . Triumph Tiger 955i. CURRENT : 2004 Kawasaki Z750 and LOVIN IT !

[matthab]

Well my injection has just failed in my PUG Jetforce 50 Tdsi, but its covered by warrenty so not that pissed off.

but i do notice it has more poke and bettwer fuel eccomoney (or however u spell it) compared to other peds!

Shame mines still restricted

[Kickstart]

Hi

Fuel injection comes in many shapes and forms. Most car systems work off an air flow meter / air mass meter (with further fiddling based on feedback from the lamda probe). Reacts a bit more slowly.

Bikes often use systems mapped off the revs and the throttle position. Reacts very quickly to cack handed inputs.

Fuel cutoffs are quite common on injection systems. Cut the fuel totally when the throttle is shut.

Bikes are produced in far smaller number, so it works out more expensive to map them properly per unit sold (or cheaper and just don't bother mapping it properly). Honda seem to have particular problems mapping fuel injected bikes.

There are some hideously badly set up carbs on cars as well. Trying to get carbed cars through 70s US emissions rules was a nightmare (and injected cars were pretty rare, Alfa getting away with far more performance at the time by using mechanical fuel injection in the USA).

Also cars are a hell of a lot heavier so the effects of opening the throttle are far larger!

All the best

Keith
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[Jebus]

the connection between the "driver" the throttle and the reaction from the vehicle is far more direct on a bike than a car, a car big and heavy so things happen a bit slower and get damped out a bit, on a bike got no weight to dampen the response out and the massive power to weight ratio also play a part. I am sure if you got in a massive hp car then you would think the fueling was a bit mad.

I like carbs, not from any riding experience but from how they work they respond to the air flowing thru them all the time and dont need a computer to tell them what todo, fuel injection is better and its just practice for the bike engines to get it right, ducati have got it well sorted apart from a bit of a lumpy engine low down but that may be because its a twin. honda seem to have problem because they problerly over engineer everything and want maximum fuel economy,

thats my 2p on it anyway
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2nd time around CBT: 8/9/11
125 Varadero

[extreme3d]

Perhaps one of the biggest perks to fuel injection is only really noticed on cold days. I just hit the engine start button and away I go. No having to mess around with chokes and/or waiting for the engine to warm up. The ECU takes care of all that for me

[Marci]

[finpos]

His has got a stacked bargraph consisting of about 15 leds. It does a fancy knight-rider type thing when you switch it on, then the bottom led lights up, unless he revs the bollocks off it, then the second one up occasionally flickers.

He's also saying it's started popping on the overrun, so I think he's spent a lot of cash to replicate very lean carbs on his fuel injection. You can't beat progress.

finpos.

[Marci]

Tell him to look at the manual...

https://www.powercommander.com/man_chp6_pg21.shtml
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FAB-Racing MiniMotoSidecars - Back with a vengeance - F1 Class 2011...
CBR170 engine, custom chassis - www.minimotoscene.co.uk

[gixxersixx]

One of the problems with fuel injection on bikes is due to engine size, the smaller the engine the smaller the quantity of fuel needed per cylinder. This is why its taken so long for bike manufacturers to get a system that works properly. Apparrently it wasnt just a case of making smaller injectors. Power commanders piggy back the standard ecu. The best way to set them up is with a dyno session. With the correct equipment the fueling and ignition can be set up so its as near as perfect for each part of the rev range.
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