Part 2: The Reconstruction

Was that with the ECU connected? Test again with it unplugged.

beetle wrote:

Was that with the ECU connected? Test again with it unplugged.

ECU unplugged. Just testing the harness, between sensor connector and ECU connector.

That's not good. 20Ω is an interesting value. Not really a dead short. There's no crud in the connectors, by any chance?

Nope, connectors are clean.

While I'll leave the heavy diagnosis to people more qualified than me I would say that the old saw about 'Italian Electrics' no longer holds water. I've been working in Italian stuff since the seventies and Guzzi were always pretty good. Morini? Laverda? Awful!

Modern Guzzis? I've had two bad looms, both on Breva big blocks. Otherwise? Nothing......

Pete

I don't believe a loom can just "go bad". There must be unseen damage. Is the tank off? At this pont I'd be pulling the tank off and disconnecting the intake sensor as well. They have a common connection to pin 20. Recheck everything.

Yes tank is off, air temp sensor disconnected, harness is all visible and there is no obvious damage. I clipped off a few of the zip ties I put on, wondering if they were too tight. Observing the resistance while moving the harness showed no change.

One thing I am wondering is if the problem I had with the alternator shorting out could have burned something out? I know with fuses etc it should not not be possible for a wire to actually burn out due to over current, but it’s the only thing I can think of.

I think my next step will be to try to trace the point of failure in the temp sensor wire itself, and possible run a new one. Worst case, I end up needing to replace the harness. It will be a pain to do so with the engine and airbox in place though!

Any additional opinions on this as a next step? Also, is it possible to remove the entire airbox without dropping the engine?

If it turns out that you have only one dud wire in the loom, why not run a new wire externally to the loom, and solder it in to the plugs at each end?

Airbox will just pop out, no need to do anything extreme.

OMG I'M SUCH AN IDIOT!!!!!!

This is too embarrassing to reveal, but since I've wasted everyone's time with this problem, I owe it to you all to suck it up and admit what a ridiculously bone-headed OBVIOUS mistake I made!

No, I can't say it, it's too stupid. I will only leave these clues:

1. The engine temperature sensor and fuel injector use the SAME connector type. (Temp sensor is color-coded, however, for people who have even minimal powers of observation.)

2. Fuel injector has a resistance of 15-20 ohms

3. Running without an injector connected tends to reduce power output somewhat.

4. Following bizarre and unlikely explanations for a problem before thinking of the obvious, likely ones is something to be ridiculed and mocked without mercy. Please, feel free

Oh ho!

You're brave to admit such a bone-headed mistake. I laughed out loud when I read your boo-boo.

Tee hee!

Cred for joining the complete knob club.

beetle wrote:

Oh ho!
Cred for joining the complete knob club.

Ooh, I should be earning lots of cred owning this bike, based on my performance so far

I'm just relieved you didn't take the engine out & replace the wiring loom !....thanks for sharing the pain & the glory as it will help us all avoid the same 'simple mistakes'

Mate it would not have happened to me as I would not have had the balls to undertake what you have done. Clearly you have just attained a massive learning curve throughout the whole project and its a big credit to you. Now go ride the pants off her.

For me, the relief of finding the problem, outweighs the error, and I have made many.

Thanks for the words of encouragement! It’s running great! There are still a couple of minor things to straighten out, but I’ve got my bike back again, looking better than ever.

Plus 1! I wouldn't have the balls or the wherewithal to undertake this job so you've definitely earned some Ghetto cred!

Damn! I mentioned a couple of minor things to work out? Thanks to one of those “minor” things I am now stuck at a gas station with no way to ride home

Minor thing #1 was just a burned out headlight bulb, which I replaced. Yay.

“Minor” thing #2 (quotes required this time) was that the clutch was feeling weird. I thought I just needed to bleed the hydraulics, since I had to disconnect and reconnect the line when I put the actuator back. But I added some fluid and pumped it a few times and it seemed to be working fine. So I went on a ride.

Stopped for gas and now I can’t release the clutch. The lever is solid and will not pull in. The clutch is not engaged, i.e. I can still roll the bike in first gear.

What could cause this? I have time to think about it while I either try to get a tow or push the bike 7 miles to home.

Could this be caused by adding too much brake fluid to the reservoir? Maybe it expanded with heat and now it’s activating the slave cylinder. Maybe I just need to bleed fluid some off?

I'm not sure it would get hot enough to lock up in just 7 miles.

Bleeding it is the first thing to try.

OK, thanks, I’ll try that when I get it back home. I was thinking of getting tools and doing it here it the gas station parking lot, but I’d rather be in my garage with everything I need, so I’m paying $135 for a ride on a flatbed. My wife STRONGLY discouraged the “push it home” idea

I would have just cracked the bleeder with a rag under it. Isn't there a spanner (wrench) in the bikes toolkit?

Unfortunately no, I checked. I would need two wrenches to hold one side and turn the other. I need to add an adjustable wrench to the little toolkit under the seat! (It’s nice and easy to get to the bleeder on this bike.) But I already called for the flatbed

Damn she looks fine on the back of the flatbed

So bleeding the lines made it work again but I don’t trust it. Look at all the crud in the reservoir!!! Is that normal? I feel like I should clean it all out.

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Removed the old fluid, cleaned out the reservoir, refilled and bled it through. Clutch is working great so far, just did a 10 mile fun ride and the clutch actually feels a lot better than it ever did. Go figure: there was crap clogging it up all along.

That ride was so much fun it reminded me why I don’t care how much time or money I spend on this thing, it’s all worth it