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.

OK, I got Raven on the dyno and a wide-band O2 sensor stuck into her exhaust pipe. (Ooops, sounds a bit rude doesnt’ it?) Anyway, 2 hours later, I had a working fuel map.

It’s a bit different to what I was expecting to see – the bottom half was running way too lean, and the upper half was way too rich. Although I think that the bottom end could do with leaning out a fraction now.

The downside to all this is that Raven has been parked under a cover since about Easter. Now that the EFI project is proven to work (and is working fine!) I no longer have the motivation to finish the job (and fix the blasted oil leak, along with getting the exhaust valve guides replaced). I’ve ridden her a few times over the months, and she is a fun thing to hoon around on, but the “fun” has gone out of owning her.

Perhaps it’s time to find a new owner for her….

The big news is that I have Raven booked in for some serious dyno time down at MegaCycle. With a wide-band O2 sensor, I should be able to get the fuel map pretty well sorted out without too many hassles. The advantage of working on the dyno is simple – I can hold the bike at a constant RPM and throttle position and get the map sorted out. No need to try and extrapolate backwards from datalogs, no need to try and remember what’s happening as I’m riding, no need to watch out for cars.

The only worry I have at the moment is that she’s burning oil (and a reasonable amount of it), and that’s what’s killing my O2 sensor. I don’t really want to kill Ken’s WB sensor.

I’ll let you all know how things turn out…

Speed-Density is dead! Long live Alpha-N! Yes, I have switched algorithms, and let me tell you, it’s much better now.

I have the fuel map mostly sorted out (I hope! Now, where have I said that before?) for most of the lower half of the RPM range. Cruising at about 80km/hr in top gear is smooth as silk. It’s still running a bit rich (going by the seat-of-the-pants) past about 1/2 throttle or so, which makes the engine sound rather lumpy and rough. Cold starting is interesting, it takes a couple of goes to get the engine to fire and continue running. Once it’s running, though, and past that first 20 seconds of coughing and farting, it idles quite well.

One thing that I have noticed is that I have to change my riding style. No more can I come into a corner one gear too high and rely on the bike to slowly accelerate. I have to come into the corner in the right gear, at the right engine speed and accelerate smoothly away – if I don’t, it just bogs down and goes nowhere as I open the throttle. Whether this is due to the incomplete tuning (including those pesky Acceleration Enrichments) I haven’t been able to tell yet.

I’m beginning to have my doubts about the EGO sensor, too. It seems to want to indicate that the engine is running very rich, even when it’s one touch away from stumbling because it’s too lean. I guess that if worst comes to worst, I can always disable it and simply run in open-loop mode.

To cut a long and painful story short, I think I have the base fuel map down pretty well. There are a few mild stumbles when keeping a constant throttle, but some datalogging and some thought should be able to sort something out. A session on a dyno is on the cards, too. Preferably one that has a wide-band Exhaust Gas Oxygen (EGO) sensor handy.

I just wish I had a working speedo – then I could see just how fast she does accelerate with the right fuel amounts and a healthy dose of acceleration enrichment enabled.

A word of advice here – if your fuel calculator says put in ‘X’ amount, then put in ‘X’ amount! Don’t piss around trying to think you can out-smart it. You can’t.

Ah yes, datalogging. I have a borrowed Palm Pilot that can act as a datalogger, I just can’t get the data out of it! So it looks like I might have to strap my laptop to the bike somehow and go for a spin. I’m really not looking forward to doing that. Of course, having the laptop present means I can make quick adjustments on the side of the road. Hopefully.

If you do use hacked up throttle bodies, like I did, you’ll need a little stopper to hold the butterfly valves open slightly at idle. Otherwise your engine will not run. You can quote me on that, if you like. grin See the picture below.

How to clean your Exhaust Gas Oxygen sensor – a careful burning with a blowtorch. Just be careful not to get it too hot.

Yet another bracket – this time to hold the throttle slightly open.

It’s not elegant, but it works – although I got tired of plugging that cable in all the time.

The tuning software is Windows-based, so I have to run VirtualPC on my Apple laptop.

Datalogging, the hard way. Maybe I need a smaller laptop….