My bike died today during a ride and I'm not finding the cause

+1 Holy cow.

 

SQLguy,
So you are a engineer or in school for engineering, mechanical engineering? That is a bunch of work. Holly Cow!

 

Software engineer. Majored in computer engineering. Was an electronics and avionics tech for several years as well. I do better at the electrical and electronics stuff. I hate plumbing.

As for the amount of work... it wasn't all done at once, and it wasn't all required just to get the bike to run without carburetors. Some people will use GSXR600 injectors, fuel rail, throttle bodies, and fuel pump. That's easier in some ways. Probably a bit more expensive for the parts. But it doesn't have closed loop idle control, and sticking with stock ignition means finding somewhere else to mount the ECU. No idea how the final result compares, but I would think that not being able to do sequential injection, or even precisely timed batch fired injection, and not being able to control ignition, would make it harder to get the most efficiency and driveability.

Mostly, I like my XJ and I hated those HSC32s. The Keihins on my XV750 seem a lot more forgiving. With fuel injection, there's no church of clean, there's no multi-hour processes to try to adjust for a change in exhaust, or altitude. There's no starter fluid or propane after the bike's been sitting for a couple of months. There's no playing with the idle or choke when it's cold, or hot. It's just turn the key, press the button, and ride.

 

Not to take anything away from what you've done, but when do you think the work balance tips /tipped in favour of your efi? In other words the work for all that "fiddling" compared to the work for efi?

 

For me, the very first time I didn't have to see a stuck needle causing fuel to overflow a carburetor. Which was probably 10 years ago at this point.

 

I know what you're saying - then having to drop the oil you just changed...
My vmax would allways start first time without enrichment, then stop. I never quite worked out why, and had never stripped the carbs. When I removed them to fit my rebuilt set I couldn't believe it - there was a puddle of fuel sitting above each inlet valve that was closed!

 

Thanks for sharing some of your back ground and determination for the project. Have you thought about putting piggy back coils on her yet? That would be an interesting mod that could be done too. I it once on a Bandit 1200 and really helped that bike out.

 

Piggy back coils? I'm not familiar with that. Is that for suspension or ignition or... ?

Anyway, I put the bike back together today. After all this, with some repeated readings, it was just 1 and 3 intakes that each needed a shim one size smaller. 270 to 265 for #1, and 280 to 275 for #3. All other valves were in spec.

At first I thought there were other major problems, because I had a hard time getting her started. I guess it must have been air trapped in the injectors, but it's not taken that long to purge them before. After a couple of minutes trying, checking things, trying again, getting some attempts to run, she caught and started running pretty well. Revved up OK and very good throttle response. Good restarts after shutting off and starting back up.

The idle does seem a little rougher than I remember - at least cold. Maybe need to tweak the tuning a bit more there... but, I'm thinking of making another intake manifold. When I made the current one, I didn't have welding equipment to weld aluminum, so I made the intake out of brass and copper and soldered it with silver solder. Overall, it's pretty good, but I think I could do better for even pipe lengths with a siamese design and aluminum pipes. The welded aluminum should also be more reliable, and welding should make it easier for me to position the injector ports exactly where I want them. I ordered materials for an aluminum manifold, and will probably hold off on much retuning until I see how that works out.

The bigger issue, though, is that I still don't know what caused the intake cam to jump one tooth back.