13 January 2009

EFI Made Easy

I just got my monthly (approximately) Royal Enfield Community e-Newsletter. Go subscribe, it's free. It's all atwitter about the first new model in 40 years.

However, Royal Enfield is also aware that many customers have long preferred to do their own repairs. For this reason, they insisted that a mere mortal with no special tools should be able to diagnose and repair this system. Any EFI can be made like this, but most manufacturers choose to make it a deep, dark mystery to keep the revenue flowing.

With our system, the "Check Engine" light will go on if something is not right. If that happens you take the following steps.

Remove the seat

Find the wire that is attached to nothing. This wire comes from the EFI "brain".
Touch that wire to the frame or any other ground

The check engine light will start to blink in a sequence of long and short blinks. For example, six short and six long. The sequence indicates which component is malfunctioning. Look in the shop manual to decode the sequence. In the example of six short and six long blinks, the sequence indicates that the crank sensor is not working correctly. Check the wiring connection to that device. If this clears the blinking, you're done. If not, replace the sensor and then you're done. If more than one unit is bad, when you clear the first sequence another will start but that is very unusual.

The Royal Enfield is very well-mapped, which means the stock computer unit programming is excellent. It evens compensates for changes in altitude that would require jetting changes in a carburetor bike.

An interesting side note is that Royal Enfield required that Keihin map the unit to over 18,000 feet. They took an instrumented to the Himalaya's to test drive it on the world's highest road. As a point of reference, oxygen is required after 14,000 feet in an aircraft, and most normally-aspirated planes fly no higher than about 13,000 feet. However, the Royal Enfield is used extensively at high altitudes by adventure bikers (try that with your GS1200). Those of you in Denver should be well-covered!

This will take care of 98% of all repairs on the EFI unit of the Royal Enfield. Now how simple was that?!

I can get trouble codes out of my '92 Dakota in just about the same fashion, but it requires turning the key three times. Simplifying that took some doin'. Heh.

What owners will do as these bikes age about all the other wires that are not attached to anything remains to be seen...

Also, I'm at slightly higher altitude than Denver and my stock carburetor jetting works fine. It did require about 1/8-turn on the mixture screw to idle right.

Also, mine doesn't have a 'check engine' light, but here's a hint: since the headlight is lit by rectified voltage directly from the alternator, if the headlight came on, so did the engine...

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