Tuesday, October 31, 2017

Heart Transplant and Dumbassery (A Bad Combination)

In early July this summer STella stranded me on the way home from work. She slowly went to sleep as I rode home, gently losing electrical functions until all the gauges went dead and she started to buck and sputter...and finally died. "Dang. I knew I needed to replace that old battery!"

Fortunately I was within striking distance of a battery shop and they had mine, so 30 minutes later I was back on my way home with STella purring like a kitten. Then she went on the center stand for 6 weeks while I was out of town. When I got back I was ready for a ride. That next Saturday morning I was off for a little fun in the twisties...but STella again did her sleep to die routine. Head Slap! Dumbass. You assumed it was a bad battery. The battery is fine. She is not making juice!

Yep. My rush to get out of town and my rush to judgement left me stranded again. This time my long-suffering wife came out with some jumper cables. STella got enough charge to make it home and then the fun began. A quick look in the manual revealed the alternator was buried so deep in the bike a sensible home mechanic won't try to dig down to get at it. But since I do not suffer from being a sensible home mechanic, the hunt was on.

Diagnostics were on the table first. A blown fuse would be a much easier fix, but alas none of the fuses showed the slightest stress...so the dig began.

As I have said many times, STella is like any beautiful woman...the hardest part is getting her out of her clothes. After that, things go pretty well. And so it was. After the the tupperware was gone, the tank was next. Man this bike has lots of parts! They all went into labeled baggies. The tupperware, mirrors, and driving lights went to safe storage spots. She looks pretty good naked for a 59k mile gal, huh?


Under the big plastic air box lies the fearsome challenge of the job...the throttle body assembly. It is a tender, very expensive aluminum casting with more hoses and wires than Medusa has snakes. And the Throttle Body Assembly is notoriously difficult to remove, despite the fact that it just sits on four rubber boots and is held down with nothing but hose clamps. Nevertheless, too many guys have bent or broken sensitive items connect to the throttle body and even the casting itself, to say nothing of other calamities like knocking the bike over while trying to lever it out of the bike.


After lots of reading and some soul searching, I settled on my plan of attack. I had some nylon strap and a piece of pipe. After all the boot clamps were loose and the boots had a dose of silicon spray, the strap went around the cast piece protruding from the upper right corner of the Throttle Body casting. From there it went around the pipe, which was laid across the frame on cloth pads, perpendicular to the bike's direction of travel. Slowly turning the pipe tightened the strap until that corner popped free and the rest of the casting rolled easily out of the other three boots. Whew! That was terrifying.

Disconnecting a bunch more electrical plugs and hoses, lifting the rubber mat that separates the throttle body from the top of the engine, removing the radiator and thermostat and all those hoses you see in the photo below...and finally it was all clear. The alternator removal was in sight. Unfortunately one of the three mounting bolts is not. It is under the alternator in a tiny space that cannot be seen by anyone but Superman (with X-Ray Vision). But the drawings said it was there so the hunt was on. Do not attempt this with anything but a 1/4" drive socket and a 6" extension. Everything else is too big to fit.


Eventually my socket found the bolt head and she backed out cleanly, leaving only the Oil Pressure Sender in the way. With that removed, the alternator slid right out, pretty as you please. It was time for diagnostics again. Before ordering a $500 electrical part, I wanted to be double dog sure she was really bad. After all, the unit has an integrated voltage regulator which could have also been the problem and that is a cheaper fix (although one may doubt the wisdom, after this big dig, of putting a 59k mile alternator back in the bike with just a new regulator). A little ohm meter testing quickly revealed the main winding in the rotor was wide open. Good enough for me. Let the spending begin!

Partzilla was at least $50 cheaper on the alternator than any other vendor and they seem to be stone cold reliable, so they got the order. During off hours I had been looking at the maintenance schedule for STella to see what else I needed to get done while she was naked.  The fork seals and bushings, plugs, plus brake and clutch fluid were next, as well as new coolant. Remarkably, Honda fluids (fork oil and coolant) turned out to be significantly cheaper than other after-market suppliers. I went with my tried and true Castrol for the DOT4 synthetic brake and clutch fluid. My plugs are always NKG Iridium units. All those parts went on the list too, along with speed bleeders, just for fun.

But trepidation hung thick in the air. Soooo many wires and hoses and little parts. Jeez. Is STella ever going to run again?

Parts arrived at last and reassembly got underway, starting with the alternator itself. Easy so far. Now for the rat's nest of hoses and wires. Well, hoses. Wires are easy. Plugs are keyed. The harness is cut to length, What can go wrong? But hoses! They are just hoses. No labels. No keys. I have fuel, air and water all plumbed in here. What if I swap two of them? Jeez.

Well...it wasn't so bad. The hose kinks and the fits seemed pretty natural. Hose types were pretty easy to determine by inspection. No real problems. So...time to fire her up. Just to make sure.

STella fires right up. Awesome. I didn't drop a wrench down the intake manifold. But dang. She is running rough as a cob. What the heck? I can get her up to 3k RPM but then she fades out and dies...sometimes with a disconcerting CLANK. WHAT HAVE I DONE?

Take it all apart again. Check every connection. Seems ok... Test start again. Same crappy idle. Same stall. Same clank. Oh boy. This is bad.

Time to read the whole chapter on the alternator. Nothing new. Ok. How about fuel injection. Hey...this baby has a diagnostic computer built in! The Injection Fault light blinks out trouble codes! Cool!

Throttle Position Sensor error.

Volt meter time. Wires good. Sensor functioning. Sensor to harness connection working fine. Check again. Follow the wiring color codes. All good.  WTF.

Ok. The book says she will default to a basic idle setting if things look bad. What the heck. Unplug the TPS and see what else the computer says.

Bad Pressure Sensor.

Fine. Back to the meter.

Just a damn minute... Why are the color codes on the Pressure Sensor plug identical to the wires on the Throttle Position Sensor plug? OMG. These plugs are the same size. The same shape. THEY ARE KEYED EXACTLY THE SAME.

What a dumbass! I assumed if they plugged in, they were in the right place. Who would put two different plugs on exactly the same length of harness wire using exactly the same key? Nobody would do that. Nobody would allow the wrong plug to connect to the wrong sensor? Right?

Wrong. One is blue and the other one is grey. Look at the color photo (not the black and white photo in the service manual). Lower left corner. The blue one goes...you guessed it...on the Throttle Position Sensor.

Swap the plugs. Error light is gone. STella fires up and revs like there is no tomorrow. Whew! The CLANK had just been a misfire brought on by bad mix.

Moral to the story: COLOR PHOTOS while disassembling! (At least the first time, before you get the hang of it.)

Moral #2 to the story: It is ALWAYS your assumptions that send you to hell.

Moral #3 to the story: Read the book. Read it early. Read it often.

Next...Fork Seals and Give Me a Brake!








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