Author Topic: Weird root causes of problems  (Read 906 times)

Offline GeorgiaGuzzi

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Weird root causes of problems
« on: July 16, 2021, 07:31:44 PM »
So I figured I’d share an ongoing Kubota saga. One of our customers had a problem with their BX (the tiny ones) series tractor losing power intermittently. Original diagnosis was debris in the fuel system. All filters and fuel changed. Delivered unit back to the customer. They call up a couple days later saying it’s doing the same thing again. But only after running for a while. Brought the unit back, tested it out under load (mowed in the demo field for a while). Sure enough, it would lose power then pick back up. Mechanic started going thru the entire fuel system again. He took every fuel line and filter and separator off. He finally found the problem. A dirt dauber had gotten in the pickup line! After a while it’s body would get sucked up and block the line. The tractor would lose power, the suction would reduce, and the silly thing would drop down again, allowing the tractor to run fine again! Put the system back together, delivered it back to the customer. Last week the customer called up AGAIN saying the tractor was leaking fuel! Went back, picked up the tractor again, and started tracing for leaks. We were hoping that the tech had forgotten to secure a fuel line, but no such luck. The fuel pump was leaking from its housing. Ordered a new fuel pump Monday, it came in this morning so we installed it and everything is hunky dory again! Dropped the tractor off this afternoon. I’ve made 3 round trips to that customers house now. I don’t even have to print out directions anymore! We ate all those trips and whatever was not covered under warranty in order to try to make the customer happy. All that time, effort, and expense BECAUSE OF A BUG!!! Sheesh!

So what weird or interesting “root causes” have y’all discovered while wrenching?

Sorry for the long post.
« Last Edit: July 16, 2021, 07:34:17 PM by GeorgiaGuzzi »

Offline Tom H

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Re: Weird root causes of problems
« Reply #1 on: July 16, 2021, 09:27:36 PM »
Weird issues. Glad to see that the customer was taken care of. Sorry that it cost you a few bucks.

Tom
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Online Kiwi_Roy

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Re: Weird root causes of problems
« Reply #2 on: July 17, 2021, 12:03:49 AM »
About a year ago ago I was riding my 72 Eldorado when suddenly it started to make a loud rattle accompanied by a severe drop in oil pressure, I checked the oil level, sure enough it was below the low mark so I assumed I had run a big end,
After putting it off for nearly a year I puled the engine and started to strip it down, pulled the left  cylinder off and it seemed fairly normal so I moved to the right cylinder, took the valve cover off and the rocker shaft fell out on the floor.
It turned out the 6mm bolt had worked its way out and the rocker shaft was banging on the inside of the valve cover. Of course the oil pressure fell to zero, it will do that when you open up a 6mm hole in the oil line.
I was never so happy to be wrong.
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Online John Croucher

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Re: Weird root causes of problems
« Reply #3 on: July 17, 2021, 10:35:48 AM »
As a long time owner of public services businesses, I found that treating customer's fairly is worth much more than any advertising dollars.  I get letters, notes and phone calls for helping with problems. 

I have dealt with the dauber problem before. 

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Re: Weird root causes of problems
« Reply #3 on: July 17, 2021, 10:35:48 AM »

Offline Navydad

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Re: Weird root causes of problems
« Reply #4 on: July 17, 2021, 10:40:05 AM »
1974 Kawasaki 900Z1. Fast bike, but being young and full of vinegar I thought it should be faster. So I invested in a big bore kit, new cams, exhaust, etc. etc. I got the bike together and rode it easy for the first 600 miles or so to give it a gentle break in period. You know, trips to the local market, short highway rides, things like that. Bike had 600 miles on new engine, fresh oil and filter, running strong at lower RPM and it was time to let er rip. I took it out to our local "let er rip" riding area and grabbed a handful of throttle. MY GOSH IV'E BEEN SHOT OUT OF A CANNON!!! Up to 80 MPH and then nothing. It would barely run let alone run fast. Back home I went and spent the weekend going over carbs, looking at exhausts, pouring over instructions and trying to remember my every move while building the engine. Then while looking over a sheet of instructions my buddy lifted up the seat and said "Hey, the new issue of Cycle World, when did you get this?"

 :angry: On one of my break in rides to the local market I had picked up the magazine and stuck it under the seat and then forgot about it. The mag was covering the airbox inlet. The bike ran great until the intake suction pulled the magazine tight against the intake. Magazine removed, bike ran scary fast.  :angry:

Offline cloudbase

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Re: Weird root causes of problems
« Reply #5 on: July 17, 2021, 11:18:34 AM »
I was happily flying along in a club glider years ago when my airspeed indicator went south.  Radioed the field that I was coming back and would be carrying a bit of extra speed.  Landed okay, and upon inspection found an insect in the pitot tube.  Mother Nature makes an insect that fits perfectly in every size opening of every machine.

Online Scout63

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Re: Weird root causes of problems
« Reply #6 on: July 17, 2021, 12:14:27 PM »
The first year I had my boat the diesel kept shutting down in the worst possible places, like the Chatham cut.  After going through the fuel system several times I cut open the fuel tanks and found several rodent carcasses.  They had nested in the tanks during the previous owner’s long term build project.  Pieces were getting sucked up into the fuel lines.  I cleaned the tanks out and installed inspection ports and it’s been hunky dory ever since.
Ben Zehnder
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Online Frenchfrog

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Re: Weird root causes of problems
« Reply #7 on: July 17, 2021, 02:10:23 PM »
One of the things i really wanted when i rebuilt my T 3 a few years ago was to incorporate an oil pressure gauge. The bike was a total nut and bolt rebuild and started on the first hit...but the oil pressure stubbornly stayed at 2 bar...so I put in a new oil pump ...and nothing changed.Rather than pester the workshop who had measured up the crank i took all the stripped down parts to another shop that is about two hours away.They cleared everything as being in spec so I was even more mystified.On the long drive home I had time to realise where I had gone wrong :the gauge was from one company and it's sender from another.Replaced the sender and the oil pressure was largely doubled !
never assume anything !

Online Perazzimx14

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Re: Weird root causes of problems
« Reply #8 on: July 17, 2021, 03:24:05 PM »
Homer Simpson: "To Alcohol! The cause of... and solution to... all of life's problems."
It's the ones who've cracked that the light shines through!

Offline Caffeineo

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Re: Weird root causes of problems
« Reply #9 on: July 17, 2021, 06:35:43 PM »
A friend brought his dirt bike over to put a new clutch in. He was out riding and it started slipping a lot. He and his buddies pulled the cover on the trail and could see nothing wrong so he rode back with the clutch slipping like crazy. Got the new clutch in and he takes off down the road only to return saying it is still slipping????? I get on the bike to see for myself and notice the clutch lever hitting the hand guard - not releasing all the way. Rotate the clutch to clear the guard and all is good. I still give him a bit of grief about that.  :grin:
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Online cliffrod

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Re: Weird root causes of problems
« Reply #10 on: July 17, 2021, 07:29:44 PM »
A couple of days after marrying wife #1, we went to her grandparents just over the line in NC for Christmas with family.  They lived on the edge of town, typical nice new older retirement home that replaced their much older family home across the road.  Her grandmother had a disposal-all in the kitchen sink,,which she liked very much.  During dinner prep, the sink clogged.  Being the new & completely low man on the totem pole, it was my job to work resolving it while father in law and grandfather in law supervised.  "Don't worry, when he put the disposal in, he put in a bigger line and ran it out into the gully out back...."  So I get the shovel and mattock and get to work,  sure enough, the above ground end was blocked by a mound of new & old goop and plenty of healthy growth. 

Started digging and found the honeysuckle around the end had grown roots about 40 ft up the line towards the house...  Of course, when that big long 2" diameter clump of root came out, so did everything else- like a fire hydrant.  I was able to avoid most of it, but not all.  Riding home in stink didn't make the new wife very happy.  But I think the pleasure the older men had seeing me properly initiated into their family made up for any entertained/unhappy imbalance.

So that, my WG friends, is truly a weird root cause of problems.

Next.....
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1964 Ducati 250
eccetera, eccetera...

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Offline wymple

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Re: Weird root causes of problems
« Reply #11 on: July 18, 2021, 12:26:35 AM »
I bought an old 58 Chevy truck with a 283 in it decades ago that ran quietly, but only on 7 cylinders. They had tried everything they knew (which wasn't much). It had no knocking, no oil burning, no backfiring thru the car, no nothing. Located the dead cylinder, pulled the valve cover, pushrods & valves all seemed fine. I pulled the  intake, & found a chunk of shop rag plugging up an intake runner, so no fuel/air to that cylinder. Which is why the plug looked brand new as well. They said it had ran like that for years.
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Online Kent in Upstate NY

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Re: Weird root causes of problems
« Reply #12 on: July 18, 2021, 12:16:39 PM »
A garter snake found its way into my electical panel and set off the burglar alarm.
Correctional educators don't make the criminals you fear. We make the criminals you fear smarter.

Offline pressureangle

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Re: Weird root causes of problems
« Reply #13 on: July 18, 2021, 03:31:50 PM »
I was working for Navistar Defense on their MRAPs in Iraq. The procedure for shutting your vehicle down was turn the ignition switch off, disconnect the batteries at the switch.
One truck shut off with the key just fine. But if you disconnected the batteries, the engine kept running. System voltage was 0 volts.

Well, being civilians and turrets being out of our domain, we didn't know there were batteries in the turret; they have a large diode in the charge cable to keep the turret batteries isolated when the vehicle is not charging. The diode leaked about 10volts, just enough to keep the engine ECU lit, and tied into the system on the external voltage regulator post. Since the voltage regulator tied into the vehicle batteries through the disconnect switch, the generator was not powered up and showed 0 volts. Took us 3 days to find it and only then because I disconnected the charge cable accidentally.

The motor pool guys made hay of that one.
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Offline Guzzidad

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Re: Weird root causes of problems
« Reply #14 on: July 18, 2021, 06:47:24 PM »
   In 1976 I had a XS650 Yamaha, and like a lot of us, I had removed the turn signals for a cleaner look. One night I stopped at a popular bar near my apartment and at closing time my bike wouldn't start. Had to walk home and fetch the bike the next day. Did everything I could think of given my very limited trouble-shooting skills at the time. Finally had to take it to a shop. Took them 8 hours to find the problem. The guts of the blinker flasher had dislodged and fallen against the metal case. All they did was disconnect the flasher, throw it away, and the bike started.

Online bmc5733946

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Re: Weird root causes of problems
« Reply #15 on: July 19, 2021, 02:19:00 PM »
An acquaintance brought me a Yamaha DT250 that ran fine just wouldn't rev up like it should. I rode it around a bit and performance was definitely off. He told me his brother had replaced the head gasket a while ago while he was out of town, brother swore it ran great when he was done working on it. I pulled the head, 10 minute job, wet coked up piston was obvious, wire brushed a little, very soft stuff, under all the coke I found an arrow pointing to the rear of the bike. Lifted the jug remounted piston in correct position, ran great. Rest of story brother siezed, it forgot they were running it on premix, ruined needle bearing on wristpin, piston got switched around during incompetent repair job and then lied about it. Surprisingly no damage to piston or bore only the needle bearing and wristpin.
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Offline drbone641

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Re: Weird root causes of problems
« Reply #16 on: July 21, 2021, 10:21:34 AM »
I was happily flying along in a club glider years ago when my airspeed indicator went south.  Radioed the field that I was coming back and would be carrying a bit of extra speed.  Landed okay, and upon inspection found an insect in the pitot tube.  Mother Nature makes an insect that fits perfectly in every size opening of every machine.
Same (sort of) happened to me in an F-5 back in 1986, while doing an FCF test flight. I called up a pair of guys, who were headed back to Nellis, and shot a formation approach and landing. Still a weird feeling trying to fly AOA and wind noise levels, for speed gouge. no insect, just a failure of some diaphram, IIRC
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Offline Chuck in Indiana

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Re: Weird root causes of problems
« Reply #17 on: July 22, 2021, 06:34:14 AM »
Same (sort of) happened to me in an F-5 back in 1986, while doing an FCF test flight. I called up a pair of guys, who were headed back to Nellis, and shot a formation approach and landing. Still a weird feeling trying to fly AOA and wind noise levels, for speed gouge. no insect, just a failure of some diaphram, IIRC

First flight of the season in the S1S Pitts Special. Mud dauber in the pitot tube.. :smiley:
Chuck in (Elwood) Indiana/sometimes SoCal

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Online huub

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Re: Weird root causes of problems
« Reply #18 on: July 22, 2021, 07:02:55 AM »
I rebuilt a norton commando , new powder coat on frame , new seat , nice paint on tinwork , rebuilt engine.
the think looked great!
when it was time to ride again, it run nicely but as soon as you gave it a handfull of throttle it misfired
after checking the ignition and carbs umpteen times , eventually i discovered  the new seat had a ridge on the seat pan, which under acceleration pushed against the fuse holder, dislodging the main fuse...
get off the throttle , and everything slipped back into place, and the bike ran perfectly again , until you gave it a fistfull...
that took four weeks to discover.

Offline Chuck in Indiana

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Re: Weird root causes of problems
« Reply #19 on: July 22, 2021, 04:41:47 PM »
^^^^^^  :grin: That gave me a grin..
Unlike people.. machines never confound you on purpose, but they *can* confound you.. :smiley:
Chuck in (Elwood) Indiana/sometimes SoCal

02 Scura RC
87 AeroLario
95 Skorpion tour
 
I think senility is going to be a fairly smooth transition for me..


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Harper's Moto Guzzi
Harper's Moto Guzzi. Where we still answer the phone, use the highest quality parts, and also do Transmission, rear drive, and carb rebuilds fast. Call us at 816.697.3411 and get your problems resolved.
http://www.harpermoto.com
Advertise Here