Update: October 28th, 2009

I’ve been asked to provide an update to how the EFI project is going.

In a nutshell, it hasn’t gone anywhere at all since my last update. The bike has been parked at a friend’s house for the last 3 years – he needed a bike to ride whilst his was being fixed. Luckily for me, he starts it up and lets it run for 5 or 10 minutes every 6 months or so. Luckily for him, he has very understanding neighbours!

Overall, the EFI is running too rich – dropping the amount of fuel by about 10% should sort that out easily. The MegaTune software that I was using allows you to do that quickly and easily. (It’s a simple matter to change the ‘ReqFuel’ variable or the injector open duration. From memory, it’s currently set to 5.5 milliseconds. Dropping to about 4.9 should sort things out.)

Around town, it’s not that good – it doesn’t want to idle properly, and the quick-action throttle makes it difficult to open the throttle a small amount. The revs surge up and drop back until repeatedly until they fall too low for the engine to run (and then it stalls). I had to reach down to the throttle bodies and manually turn cable attachment by hand. Even then it’s a tricky job to get it right.

I think that could be fixed by redesigning the throttle stop so that the throttle is held open a little bit more, and perhaps a bit of a tweak to the lower-end of the fuel map.

Once you get moving, it’s fantastic. Not a lot of power below about 5,000 RPM (kind of like the stock CBX). Once you open it up, however, it’s a different story. The tacho needle rips towards the redline at a great rate of knots, the exhaust howls in your ears, and the horizon leaps at you.

I didn’t get a dyno run, and I really wish I had. A ‘before’ and ‘after’ comparing the carbs to the EFI power output would be fantastic to see. I estimate that the carbs were giving me about 80 to 85 horsepower at the rear wheel, and the EFI is easily more than that.