Das Brick: 93 K75 S Renovation

[The Mighty Gryphon]

First, I think Chris Harris' comment on valves was regarding the 4 valve engines.

Have you checked the throttle position switch, that may have some effect.

Throttle air screws are set to 1 1/2 to 2 turns from bottom.  I set the last one that has the vacuum line for the pressure regulator for 1 1/2 and balance the others to it. 

Did you have the injectors cleaned?  If they are gummed up with old fuel, they might not work well at small throttle openings.  If you haven't had them cleaned, get some Techron fuel system cleaner and run a half bottle through each of two tanks of no corn gas if you can find it.  A little YeeHaa will help loosen things up. 

Last, check the timing of the Hall sensors.  It's unlikely to be off, but you never know.  No need for a timing light.  There is a cutout in the mounting plate that lines up with the case when they are in the right spot.  The factory manual has a nice photo of how they should look.

[Rcgreaves]

I'm in the weeds on much of this so I'll step to the margin and watch 

Verify spark plugs- smaller number is a higher heat range.

[Bon Jon Bovi]

First, I think Chris Harris' comment on valves was regarding the 4 valve engines.

Correct, sorry bout that. And no corn-less premium petrol round these parts, guess I'll try Techron. The injectors are 4-hole aftermarket units so don't know if they are gummy or not, but they looked pristine when I had them out.

Can't hear any clicking from the TPS, I'll have a look. And I'll pop the Halls sensors cover for a gander at that.

Clayton, bite me. 

[The Mighty Gryphon]

I'm not saying it's the problem, but the 4 hole injectors have orifices that are 1/2 the diameter of the single hole OEM injectors.  That tells the pessimist in me that they are at least twice as likely to clog up.  If the bike has been idle for a while, it's in desperate need of some run time with the Techron.

[Martin]

+1

[volador]

I'm not saying it's the problem, but the 4 hole injectors have orifices that are 1/2 the diameter of the single hole OEM injectors.  That tells the pessimist in me that they are at least twice as likely to clog up.  If the bike has been idle for a while, it's in desperate need of some run time with the Techron.

+1

Yo'all rubes must been daydreaming of the coeffiecient of MaryJoe's thighs during physics and chemistry class

What the fecking purpose of fuel filter?

[Martin]

Fuel filter or not the injectors can still be subject to gumming up.
Regards martin.

[Rcgreaves]

Correct, sorry bout that. And no corn-less premium petrol round these parts, guess I'll try Techron. The injectors are 4-hole aftermarket units so don't know if they are gummy or not, but they looked pristine when I had them out.

Can't hear any clicking from the TPS, I'll have a look. And I'll pop the Halls sensors cover for a gander at that.

Clayton, bite me. 

No ethanol-free fuel in the high desert.  Cain't breath, cain't brick.  Sucks to be you.  Like I says we'll just step back and observe.  Four day weekend thanks to Covid19.

[Bon Jon Bovi]

Oh there's non-corn petrol available, just not the super bleifrei variety...

[Rcgreaves]

Oh there's non-corn petrol available, just not the super bleifrei variety...

I guess Krautspeak ought to be expected. After all its a German machine. Here's my google search:

bleifrei. adjective. Benzin etc lead-free, unleaded. adverb. bleifrei fahren to use lead-free or unleaded petrol (Brit) or gas (US)

Bite me back atcha Day!

[Bon Jon Bovi]

I guess Krautspeak ought to be expected. After all its a German machine. Here's my google search:

bleifrei. adjective. Benzin etc lead-free, unleaded. adverb. bleifrei fahren to use lead-free or unleaded petrol (Brit) or gas (US)

Except for the addition of the word 'super' in front of that. Super we no gots here in No Cheemexico.

[Bon Jon Bovi]

More doodoo mouth on my part without actually checking first (that's why I got kicked off the MOA site I reckon). My K75 rider's manual says 89 octane or better; it's the RT that specifies 'super'. So Ima stop at the one station that has non-mandated gas and see what octane they got. 

[Bon Jon Bovi]

Bought a kit to renew the gas cap. This is the inside of the tank:









Is the bird nest standard, or the PO's attempt at an inlet filter? What about the wrap on the pump leads? It looks like the self-adhering orange neoprene stuff we used to wrap conduits on C130s. And the spigot with nothing attached?

[volador]

I'm guessing PO retro fit aftermarket 43mm petrol pump into an existing 52mm petrol pump rubber vibration damper.
Probably have that black 'Scotch-brite' wrapped around the pump bottom inlet in lieu of OE sock strainer.

OE internal petrol hose is 8x13mm 16121180040

FYI- different 43mm sock strainers

Chicom version plugs into pump inlet. Martin can verify



OE has metal mounting collar 43MM sock strainer 16141341233

[Laitch]

That bird nest isn't standard. It was probably wound around a fuel pump that had a smaller diameter than the damper opening to help lodge it into the opening. A better technique is to use fuel cell foam.

The spigot/stub pipe you've pictured was part of an anti-cavitation strategy to protect 52mm fuel pumps and was used to allow air vapor to escape from the 52mm pump strainer basket into the vapor collector on the ceiling of the tank if fuel level was low. It was connected to a pipe molded into the basket. It was a case of over-building. Mine is disconnected with no problem but I don't allow fuel level in the tank to become drastically low.

Later model 43mm pumps use a fuel sock, as has been indicated.

[Bon Jon Bovi]

Great tutorial Laitch. I guess I'm gonna take the damn thing apart; I'm not happy with the rubber-wrapped wires, can't see a strainer, and the bottom of the tank has what looks for all the world like cheese residue on it. And can't tell anything about the hoses in there.

[Laitch]

I guess I'm gonna take the damn thing apart

Good plan. The perspective is so skewed I can't visualize location of the mounting platform for the pump holder. I should be interesting.

[Bon Jon Bovi]

Good plan. The perspective is so skewed I can't visualize location of the mounting platform for the pump holder. I should be interesting.

You truly are.

[Laitch]

You truly are.

I'm going to keep fishing for compliments. It's elevating my mood. 

[The Mighty Gryphon]

Around here, no corn is normally 89 or 90 octane.  Either one runs just fine in my bikes. 

As an aside, I only run the no corn at the start and end of the riding season now.  In the fall, I run it to flush the corn out of the system before I put the bikes away for the winter.  In the spring, I run a couple tanks with Techron or Seafoam to flush out any varnish that might have gotten in the injectors while the bikes were idle for the winter.  The rest of the year I run regular 87.  I can't see any difference in performance that justifies the extra 50 cents per gallon.

[Bon Jon Bovi]

Around here, no corn is normally 89 or 90 octane.  Either one runs just fine in my bikes. 

As an aside, I only run the no corn at the start and end of the riding season now.  In the fall, I run it to flush the corn out of the system before I put the bikes away for the winter.  In the spring, I run a couple tanks with Techron or Seafoam to flush out any varnish that might have gotten in the injectors while the bikes were idle for the winter.  The rest of the year I run regular 87.  I can't see any difference in performance that justifies the extra 50 cents per gallon.

Thanks for your insight, much appreciated.

Emptied the tank by jumpering the fuel injection/pump relay pins. Got the pump out:





Can't find an emoji that adequately covers this.

[Laitch]

There should be a platform inside the tank into which the pump holder is clipped. Is there?

[Bon Jon Bovi]

There's a metal platform:



And swollen, non-submersible fuel hoses:



Some surface rust and what looks like charcoal bits sitting on the bottom, bits of disintegrating hose I imagine. The pump was not sitting in the holder and so it wouldn't pump all the gas out. Maybe a half gallon still in the tank.

[volador]

PO winner 'most original design of using A/C filter' award

Got vinegar?

[volador]

charcoal bits sitting on the bottom look like disintegrated rubber damper bits

OE 43mm VDO pump, plastic mounting ring & rubber vibration damper