Fuel injection

[R85/8]

Has anyone wangled a fuel injection system onto an airhead?

(Just idly musing, got enough projects on the go already)

[dwerbil]

Always wondered that myself, with that $1,000 Luftmeister add-on. One came up on Ebay a few months ago. Never did sell, if I remember correctly.

[R85/8]

I was thinking a bit of ingenuity and the system of an R850R could possibly be grafted on. Cheap enough bits on eBay.

Mapping it would be the trick.

[Major Softie]

I was thinking a bit of ingenuity and the system of an R850R could possibly be grafted on. Cheap enough bits on eBay.

Mapping it would be the trick.

Isn't that a closed loop system? You would want an open loop system.

[R85/8]

Isn't that a closed loop system? You would want an open loop system.

I was figuring on transposing the whole R850R system including sensors.

But this is outside my area of experience, so enlighten me. Why would an open loop be preferable?

[r90s]

You know that Silent Hektik is all over that, right?


http://www.silent-hektik.com/ICM_Boxer_1.htm

http://www.silent-hektik.com/ICM_Dros.htm

Cheers,
Jon-Lars

[Major Softie]

I was figuring on transposing the whole R850R system including sensors.

But this is outside my area of experience, so enlighten me. Why would an open loop be preferable?

Open loop still uses sensors, but does not feedback.

Open Loop: sensors measure things such as vacuum, throttle position, air temp, engine temp, and sometimes volume of air moving through the airbox. It then picks an appropriate mixture according to an internal map.

Closed loop: does all of the above, then measures the resulting exhaust with an O2 sensor in the exhaust, and re-adjusts (corrects) the fuel input for a more perfect mixture.

Closed loop is necessary for the more perfect mixtures needed to not damage catalytic converters. IME, open loop gives a lot less sensitive throttle and feels more like carbs. Admittedly, closed loop systems have improved a lot since my first generation Oilhead, but the Duc was also closed loop when stock, and then the (off-road only) factory performance chip that came with the (factory accessory) high performance exhaust changed to open loop. It was an enormous improvement in both overall performance and smooth throttle response, although it did drop fuel mileage nearly 20%. So, while I don't know how much of the vast improvement was from the change to open loop, and how much was the significantly richer mixture, I do know that open loop is the standard on the track.

[R85/8]

You know that Silent Hektik is all over that, right?..

Their system is worth more than my bike.

I was thinking more along the lines of someone bodging fuel injection onto an airhead using cheap second hand parts, eg from a BMW oilhead or the likes of a Ducati.

[Garnet]

You know that Silent Hektik is all over that, right?..

Their system is worth more than my bike.

I was thinking more along the lines of someone bodging fuel injection onto an airhead using cheap second hand parts, eg from a BMW oilhead or the likes of a Ducati.

That could lead to a massive waste of time and money. Unless the bike your taking the injection from has the identical stroke, cam lift, duration, two valve head, comp ratio and timing curve then the mapping will be so far off it will be realy hard to chip or trick it into working anywhere near rideable.

The SH system seems really expensive but keep in mind that is a combined ignition and fuel delivery system. They must work hand in hand. I have not taken a close look yet at the SH system but I assume that the ICU adjustable for idle, midrange and WOT. Typically their quality is good, but they are hard to pry info out of.

[R85/8]

...That could lead to a massive waste of time and money...

If we were being rational we wouldn't be riding old motorbikes.

Seeing as many of us are prepared to fit different carbs and silencers to our bikes which involves much the same effort, I'm not sure that's a deterrent.

Expense? - not really. What triggered my enquiry is how cheaply the fuel injection components can be bought on eBay.

Obviously different knowledge is needed.

Doesn't look like anyone here has done it so far though.