On Sunday, I rode the fuel-injected NC30 for the first time! It’s great to finally be at this point.

Before I got to that point, there were a few final issues. After putting together, hooking up the fuel system, and verifying that all the sensors worked, I noticed that the throttle position sensor reported “20%” open with the throttle closed. I thought that seemed weird, since it should have been pretty well calibrated before, but I recalibrated it and moved on…

After filling the fuel tank, I was pleased to note air bubbles coming out of the tank connection, indicating that the air was making it out of the fuel pump housing, and when I ran the fuel pump it only took a few second for it to prime and start pumping fuel around. Glad that worked out.

When I cranked the bike it didn’t take many seconds for it to fire and the immediately rev up to the rev limiter (which I set to 8000 RPM for a cold engine). What the …?

Remember that 20% throttle? Turns out that the throttle cable end for the carbs is too wide for the GPz throttle body, and was wide enough to catch on a bolt so the throttles weren’t actually closing to less than… 20%!

Ok, whatever, I had hoped to not need to put a new end on the throttle cable but since it was also really too long for the adjustment to be able to take it all up, I cut an inch off the end and soldered a properly sized end on the cable. (I had planned for this and ordered a few cable ends of the right size before.)

With that fixed (and the throttle position sensor recalibrated again) I figured I would do what I really should have done in the first place and log the manifold pressure while cranking. This is the real test of how well the throttles are synchronized. When I did this, I was disappointed to note quite large discrepancies. I had hoped not to have to attempt to adjust the linkage on the bike since getting to the adjustment screws would be almost impossible, but no such luck.

While it requires some contorted fingers, it turns out to not be too bad to do this adjustment (probably actually easier than with the carbs) and after a while it looked pretty good, the cranking MAP is about 66kPa and there’s about 1kPa difference between them.

After putting the bike together again I was rewarded with a pretty nice idle. I put the seat and fairing back on and took it for a spin on our street. It at least pulled well enough that it was rideable below maybe 5000 RPM, so I went out on the super-wide road we have nearby and tested it.

It ran, but certainly did not run well. It didn’t want to rev past about 5000 because of lean misfires, and the front and back cylinder pairs registered quite different air/fuel ratios, by 10-20%. But from now on, it’s all about tuning. No more fabrication necessary!

(Sorry, no pics or movies, I will attempt to make a recording later.)