power loss whack - '90 K75

[herseyb]

 :falldown:

Well, I was all loaded up and trying to hit the high speed ferry in MKE for a long weekend of moto-camping and FINALLY testing the dawn 2 dusk qualities of my taintilator seat when the ole hoss pooped out on me on the interstate.  :cowpoop:

I had found a gap in the rain and was humming along at 75 mph indicated for an hour, when I looked down and realized I had slowed to 65 and the throttle was wide open.  No Bueno.

I got off and limped another 20 or 30 miles to town with performance decreasing by the minute.  Anything about 4,000 RPMs and it would wig out, also worse heading up hills.  The final hill into town it started bucking, and I waited for a ride home and collected it the next day with a trailer.

Still starts fine and sounds fine under no load, and I rode it  into the shed under it's own power in 1st gear.

The only other symptoms were a kind of brief fluttering power loss that cleared up when warm while I was riding a few weeks earlier.  This wasn't a flutter thought, this was more like anemia and bogging down if I tried to get above 4,000 RPM.   

Any thoughts or game plans? 

[Scott_]

When was the last time you checked the valve clearances.....
I overlooked it when I acquired my 1st brick and I burned a couple of exhaust valves shortly there after........
If you can, you might want to run a compression test.

When mine went out on me, I was cruising same as you, 65+ and then just a slow steady decline and eventually no power. Barely enough to get me home 60 miles with just 2 cylinders and no more than 3rd gear.....
When I was diagnosing it I thought it might have been the head gasket as it was #2 and #3 that were out. Mechanic pulled the head and found the bad valves instead.
YMMV

[Laitch]

A compression test will indicate a gross failure like a burned valve and is a relatively quick test to perform. Before you do that, look into the fuel tank for disconnected lines and check fuel flow at the rail.

[Scott_]

Then there is the fuel filter...... How old is it.

[herseyb]

Hmmm,

  any recommendations for a fuel pressure tester and a compression tester?  Price/reviews seem to be all over the board.  I'd rather spend $20 than $100, but I'd rather get one that is going to actually work even more.

[Martin]

Fuel pressure tester is pretty easy a gauge and a bit of plumbing. My gauge was salvaged of a compressor regulator but you should be able to pick up a new one for under $20.00.  I normally tap into the return line. Harbor Freight should have a suitable compression gauge.
Regards Martin.


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[Laitch]

any recommendations for a fuel pressure tester and a compression tester? 

You're not telling us much. Did you disconnect the fuel line to the rail, press the starter and have moths fly out? Looked into the tank for fish or crabs clogging lines? Don't go all gizmoey yet. One test at a time.

[caveman]

If you pinch off the outlet hose your pump should scream instead of whine. It's not high tek but you should have something already to do the job. Also you may find a split filter or hose in the tank.
I will send you a PM

[herseyb]

After a nice good ride on k1100 I finally balled up  to follow Laitch's simple game plan of visual inspection of the tank vs. googling while at work.

OMFG THERE IS GREEN PEALING SOMETHING GOING ON!!!!    Plus chalky bullshit failing my cap seal.

WTFBBQ I think there might actually be crabs.    Cheezus...  what n the hell... 

 


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[The Mighty Gryphon]

Yikes!!!!  Is that your tank?  What have you been running in your Motobrick?

[herseyb]

swear to god, you'd think i'm running uranium or something.

I wonder if it is failing tank liner?  Northern fuel tank liner says water will break it down, and it can stain gas green.  I am the 3rd owner so I don't know the full history.   That's stretching it though because it's been living inside - so unless I get bum gas...   I really dunno. 

Can I pressure wash the inside of the tank if I pull the pump and hoses out?

[herseyb]

Rodger Dodger.  I will put it in a barrel with some blankets and make the barn cats roll it around the yard to help agitate the vinegar 'n' rocks.  I did see he made that tank purty!

[volador]

If the above does not work try MEK, acetone or lacquer thinner for removal of the lining.

Tank liner in a can like Red-Kote "For clean-up use methyl ethyl ketone, acetone or a quality lacquer thinner with no alcohol in it."

Mask off your paint before using any of these products

[Scott_]

Almost makes one wonder WHY it was sprayed with liner in the 1st place....... What's to be found after it's cleaned out, corrosion holes in the bottom seam?