Author Topic: That mysterious K75 Fuel Pump Rubber Damper Demystified today.  (Read 1698 times)

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 508
That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« on: September 05, 2018, 12:08:08 AM »
So I remember certain members of the asylum preaching the gospel of setting a benchmark on this hidden fuel system time bomb called the vibration damper. 

Now in year 3 of this illness Im selling a fuel tank to a fellow and he declined the fuel pump.."ok so I'll just remove it" No big issue with the tight fit with my size XL mits though vexing its when that damper came up out of that pristine tank and crumbled all over my bench like mishandled oreo cookie. "Now thats Whack"  I actually said that...

So attached are some pictures

and heres the bad news....$100 replacement!!! "holy crap"

03   Vibration damper      1      01/1993   16121464628   $99.47      +core

but cheaper than a tow while touring Canada soon...

Kudos to those of you ..you know who you are who make this place very educational....These machines are so very satisfying but holy crap can they bite you if you don't do maintenance. 

Top of the list for my 94 is to inspect this stuff over the winter.  KMev you out there? Did you recently pull the fuel pump?  Cheers all.

  • Livingston, SW WI. USA-"With the good earth all around."
  • 1994 K75S ,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

Offline blackie1

  • ^ Proficient Motobricker
  • Posts: 162
  • christchurch nz
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #1 on: September 05, 2018, 01:12:40 AM »
thanks for the pics
out of interest how many kms did this bike have on the clock?
  • new zealand , where else would u want to live, really
  • 1991 K75RT naked 40,000kms

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 508
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #2 on: September 05, 2018, 01:25:36 AM »
108,000 miles. The learning for me is that everything else was comparably well to very well maintained. But this is a hassle and a WHACK (not my term) pricey replacement part. 
  • Livingston, SW WI. USA-"With the good earth all around."
  • 1994 K75S ,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 6207
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #3 on: September 05, 2018, 06:56:05 AM »
and heres the bad news....$100 replacement!!! "holy crap"
but cheaper than a tow while touring Canada soon... 

Top of the list for my 94 is to inspect this stuff over the winter. 
It has been emphasized here for years hear that tanks, pump mounts and other components of the fuel system in newly-purchased used K-bikes should be inspected thoroughly before riding.

Anyway, this damper doesn't reach your holiness scale; perhaps it attains anointed status. It certainly will if it's purchased and used. :giggles
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 508
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #4 on: September 05, 2018, 08:19:52 AM »
Mornin Laitch. 

Where is the Best Buy on a new damper on the stack o greenbacks in my wallet.  $97 seriously?
  • Livingston, SW WI. USA-"With the good earth all around."
  • 1994 K75S ,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

Offline mw074

  • ^ Proficient Motobricker
  • Posts: 267
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #5 on: September 05, 2018, 08:33:02 AM »
I have the whole assembly new, strainer, damper, and supporting ring for $100. + shipping.
  • Michigan

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 6207
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #6 on: September 05, 2018, 12:11:51 PM »
Where is the Best Buy on a new damper on the stack o greenbacks in my wallet.  $97 seriously?
I read $57 at the link I posted in response, but there are alternatives using fuel cell foam and plenty of posts describing them. How well they damp vibration is the question.
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline blackie1

  • ^ Proficient Motobricker
  • Posts: 162
  • christchurch nz
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #7 on: September 06, 2018, 04:07:58 AM »
i just realized my question in "reply 1" about how many miles were on the odometer of this bike is irrelevant.
the "age" of that gasket is the relevant factor
i think i will replace mine as a matter of preventative maintenance in the very near future
  • new zealand , where else would u want to live, really
  • 1991 K75RT naked 40,000kms

Offline Laitch

  • ^ Quintessential Motobricker
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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #8 on: September 06, 2018, 05:58:26 AM »
i just realized my question in "reply 1" about how many miles were on the odometer of this bike is irrelevant.
the "age" of that gasket is the relevant factor
Miles on the odometer are relevant in determining the likelihood of problems occurring in a used K-bike—gaskets and dampers included. Low mileage—at this stage maybe less than 30Kmiles—and negligence in storage tend to foster more electronic and fuel problems.  The purchase of a used K-bike should always be followed—if not preceded—by inspection of the fuel tank for residue and the fuel hoses, pump vibration damper and wiring for integrity. The fuel filter should be considered a relic of the glasnost or Wu-Tang Clan eras and be replaced.

Age is a harbinger of working condition but condition can only be determined by inspection. If a damper looks good and feels good, it is good in my book. I want my moto-dollars invested in fuel whenever possible. :giggles

I inspect conditions within the tank at the beginning of every riding season as part of maintenance review anyway.
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline earlguy

  • Curious
  • Posts: 8
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #9 on: October 11, 2018, 09:37:15 PM »
This is a very useful topic. Thanks.
  • North Woodstock, NH
  • 1990 K75S

Offline Andy FitzGibbon

  • ^ Motobrick Curious
  • Posts: 108
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #10 on: October 12, 2018, 09:25:11 AM »
Mileage is relevant... to me, lower mileage means more sitting, which means more opportunities for fuel to go stale, and for ethanol to start attacking the fuel system components.

Andy
  • Montrose, WV
  • 1985 K100RS, 1972 R75/5, 2012 Suzuki DR650

Offline island_boy

  • Motobrick Curious
  • Posts: 40
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #11 on: October 12, 2018, 12:21:46 PM »
So, bear with me, as I'm a new-ish K-bike owner who bought his current 114k '92 16v off of ebay and have only been riding for 3 years...  can I tell from the top that my damper/isolator is good/bad/ugly, or do I have to remove it to tell?

Thanks!

I always seem to find these fuel-related items to monitor AFTER putting an entire fill of gas into the tank...

 :giggles
  • Auburn, Alabama, USA
  • 1992 K100RS, 1973 Honda CL360 (sold to another owner who promptly blew it up)

Offline Gibson

  • Motobrick Curious
  • Posts: 44
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #12 on: October 12, 2018, 01:21:15 PM »
My bike only had 600 or so miles on it when I got it. The rubber mount was bad, the pump was shot. I got the whole set up from Euro moto electrics. Its been running well though (3000 miles this summer). One thing also to check while you are in there, I needed to replace the o-ring on the fuel gauge plate. Mine went bad and was leaking. 
What is the conciseness on draining out the E-10 over the winter?   
  • Dix Hills NY
  • K75 ABS and R100Mystic

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 508
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #13 on: October 12, 2018, 01:33:16 PM »
I wish I had a hard and fast formula for this, here’s my attempt:

Bricks require periodic care and feeding.  An owner disinterested in doing seasonal maintenance shall we call it, might best invest in a newer ride. As, for me, the cost of professional maintenance is out of the question.

Some K bike bits are fine nearly forever.  Some will bite you if ignored, so if this is what I’m going to ride I’ll do well to eliminate potential surprises. 

Splines lubes are the obvious example.  Others, like this silly $100 rubber fuel pump damper -hidden inside the tank, and in my case in what looks like a pristine tank at first glance is the stuff not obvious but essential from time to time. That is -If I want to jump on this when the time is right and driver til I reach a large body of water, I want bits like this to be a non-factor in my planning. 

Another thought: what other bike can be acquired for 2-3k usd$ with fuel injection etc and do what these do? I’m fine with carrying a clutch cable and a fuel pump with me in my kit- this is a classic machine and that’s part of the experience.

I happened to view a video on Facebook this am about the rescue of a junkyard dog. my new Motobrick pal Szabo clearly has a acquired such a pitiable k bike animal... Blind, coated in oil, cancer etc.. I’m really not into such animal stuff ( though our pooch lives very well...), anyway they pulled the dog out from neglect and started showing it some love despite the dire prognosis. 

Everyone benefitted.  I certainly grin the more i dig into these bikes as time permits.  Cooling system and muffler post mortem later today actually!!

The pooch healed and starting paying back the love.  A lot of weird stuff makes me think about  my brick lately.  Enjoy your day.
  • Livingston, SW WI. USA-"With the good earth all around."
  • 1994 K75S ,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

Offline Gibson

  • Motobrick Curious
  • Posts: 44
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #14 on: October 12, 2018, 02:23:24 PM »
Agree. Very satisfying machines to ride. Much less needy than an airhead, and much more convenient. Lower bars are the only change I made. These bikes are timeless works of art.
  • Dix Hills NY
  • K75 ABS and R100Mystic

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 508
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #15 on: October 12, 2018, 02:26:08 PM »
Gibson if I lowered my bars id be on the tank...Without bar backs, this bike is too too for me.  Cheers.
  • Livingston, SW WI. USA-"With the good earth all around."
  • 1994 K75S ,1985 GL1200A Goldwing Aspencade, dreaming of adding a sidecar to the mix in 2019
Doing “better than I deserve”

Offline Gibson

  • Motobrick Curious
  • Posts: 44
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #16 on: October 12, 2018, 02:31:40 PM »
Ill bet you have the S. I have been looking for S bars for my bike (k75 ABS). Haven't found em yet... I am running R65 bars now.
  • Dix Hills NY
  • K75 ABS and R100Mystic

Offline The Mighty Gryphon

  • ^ Quintessential Motobricker
  • Posts: 4291
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #17 on: October 12, 2018, 05:50:26 PM »
What is the conciseness on draining out the E-10 over the winter?

I switch my bikes over to non-ethanol pure gas about 3-4 weeks before laying them up for the winter.  A shot of StaBil and some Techron in the tank and they are ready for the winter. 

I also do all my maintenance in late November into December and have all three bikes done by Christmas.  I leave the batteries in them, and start them every two weeks and let them warm up before I shut them down.  Once a month I put my trickle charger on them overnight.  This keeps the batteries fully charged and ready to ride if we get a break in the weather.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too

Offline Soggz

  • ^ Proficient Motobricker
  • Posts: 462
  • 2 wheels are better than 4,but 4 wheels are 2 bike
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #18 on: January 05, 2019, 05:56:34 AM »
Hi,I've literally just replaced my anti vibrio rubber thing. Mine was sat for 12 years in old fuel in a bike I have just bought. Mine wasn't crumbled like that one in the pic,mine had literally turned to a 'black jam' substance!
  • High rise multi-storey car park.
  • 1988 K75C, 1982 Honda CX500EC Eurostreetbrat
One More Of These,One Less Of Those...

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 6207
Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #19 on: January 05, 2019, 12:19:23 PM »
....my anti vibrio rubber thing. . . . mine had literally turned to a 'black jam' substance!
That is called a vibration damper; the "black jam" substance is called Marmite.
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Martin

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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #20 on: January 05, 2019, 02:53:06 PM »
I'm on my second damper in 26 years and still have the first which is still good and keep as a spare. I changed it 20 years ago and it is still fine with no sign of rot. My mate has four Bricks all with disintegrated dampers. His Bricks have run on ethanol fuel and have sat for long periods. My Brick has never run on ethanol fuel in the 21 years that I have owned it and the longest it has sat was 4 weeks last year. I have occasionally drained my tank and I have never encountered any signs of water and there are no signs of corrosion. I don't even run our car on E10 even though it was designed to run on it.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #21 on: January 05, 2019, 03:27:43 PM »
My Brick has never run on ethanol fuel in the 21 years that I have owned it and the longest it has sat was 4 weeks last year.
In contrast, my brick has used only E10 89(AKI) gasohol for the last 50,000 miles. It is parked in unheated indoor storage for six months per year with a tankful of fresh, stabilized E10. The other six months it is parked outside under a moto cover in all weather conditions and ridden at least 20 miles daily but more often over 50 miles daily, rain or shine. Its pump mount damper is still in good condition but I renewed all the fuel cap gaskets this year.

Outcomes can depend on the quality of fuel purchased from the dealer, too. Idleness is the main enemy of these motos. If it is only to be ridden a few times per year, a moto's engine probably should use ethanol-free, or stabilized E10 that is replaced at least yearly for good results.

  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline The Mighty Gryphon

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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #22 on: January 05, 2019, 03:54:11 PM »
I've seen E10 do a couple thousand dollars in damage to a boat.  Hell, I've seen boats totalled by the shit. 

I would love to hear the reason why the people who have had these damages do not have standing to sue the people who make that crap, especially Al Gore who lobbied to have it mandated by federal law.

Now we're going to E15.  I guess E10 didn't do enough damage.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too

Offline Martin

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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #23 on: January 05, 2019, 04:27:52 PM »
As long as I can avoid using E10 I'll do so. E10 also allows the formation of water in the bottom of the tank which leads to acid formation and pin holing.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: That mysterious K75 Fuel Pump Rubber Damper Demystified today.
« Reply #24 on: January 05, 2019, 04:58:48 PM »
As long as I can avoid using E10 I'll do so. E10 also allows the formation of water in the bottom of the tank which leads to acid formation and pin holing.
That makes sense.

Formation of water in the bottom of the tank is a product of idleness and unconditioned E10. Phase separation—the process of alcohol in fuel attracting enough water to separate from the gasoline and drop to the bottom of the tank—can occur within three months in hot and highly humid environments. That's why its use becomes a problem in recreational boats and tools infrequently used. In that time period under those conditions, non-ethanol gasoline itself can become stale, also. Conditioning the fuel with a product like Stabil delays the occurrence of phase separation out to approximately 12 months but gasoline will degrade anyway—somewhat more slowly when conditioned and when it's in a cooler and dryer climate.





  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

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