K75 Issues

[spokes]

Hows it going guys. I have a i believe '86 k75s? Im not 100% sure haha ive had it about 2 years, i traded a friend some work for it and i am finally now getting around to working on it. the bike sat for a few years with gas in the tank  :musicboohoo: so the ethinal destroyed everything. I got a new pump out of a mustang, i read the works just as well. But now the issue i am having is since the fuel sending unit is all corroded i cant get power to the pump. trying to find a sending unit has been about as successful as me winning the lotto. I was wondering if anyone know any other tricks to get the bike running. I am at the point where i just wanna put an external electrical pump on it haha  :clap:

I am told by my pops and the guy i got it from its a nice bike and a lot of fun to ride. Im a woods rider so it seems bulky as hell to me haha here are some pics. Im told it has a corbin seat, and progressive suspension  :eek:





PLEASE HELP ME HAHA I WANNA RIDE THIS THING FIANLLY!!!  :clap:

[552255]

...be prepared for a long ride...with your wallet and toolbox.   Maybe it wont be that bad, but these bikes eat rubber parts, when resting.  Fuel system, brake lines, seals, fluids, splines, etc. may all need some attention.  Fuel system to get it running is obvious place to start.  Should be able to clean up some of the electrical units?  there is a way to test fuel pump out of bike.  Search the many great write-ups here to get great info...my worry would be the brake system:  seals in calipers, lines, and rubber in master cylinders could all be shot.  Coolant, oil, those are obvious...hopefully the sprag/starter clutch thingy isn't locked up, (again there are fixes on here for those)  Water pump, hopefully not gummed up...brake light switch, starter switch can go bad (although not from sitting I wouldn't think)  Bearings in the steering 'neck'....I better stop. 

Shoot, am I ruining your plan?  I don't mean too...I replaced an entire frame for one of these (it was wrecked), fork seals/bushings, triple tree, all bent...and I got it going like it was near new  (ofcourse it only had 14k miles on it, so I figured it was worth re-building)  Make sure it runs first before tearing into brakes, etc.  check tranny, final drive unit, if those are ok, most everything else can be replaced, there is a great many used parts online for these.

It would be a fun project for sure, it looks like a decent bike once cleaned up...best of luck!

[Scott_]

Not trying to make anyone look foolish with this question but, how are you testing for power that makes you think you aren't getting it thru the sending unit.
The fuel pump only gets power(via the fuel pump relay in the electrical box under the fuel tank) when the engine is turning. There is no "pre-charge" time to run the fuel pump when you turn the key on.

Agree with 552255 that most likely all rubber bits, hoses, seals, vac lines, etc....will need/or seriously should be replaced just solely based on age alone.

[TimTyler]

Given the overall good yet dusty look of the bike in your photos, and the fact that it has a custom seat, rear rack and shock upgrade, I'd guess the bike was likely well-cared for, at least at some point.

If it's got <100k miles on it and you're employed it's probably worth your time to get it back on the road.

[grant71]

i got a fuel sending unit 2 nd hand from James Sherlock UK and i ve had no problems since

[spokes]

...be prepared for a long ride...with your wallet and toolbox.   Maybe it wont be that bad, but these bikes eat rubber parts, when resting.  Fuel system, brake lines, seals, fluids, splines, etc. may all need some attention.  Fuel system to get it running is obvious place to start.  Should be able to clean up some of the electrical units?  there is a way to test fuel pump out of bike.  Search the many great write-ups here to get great info...my worry would be the brake system:  seals in calipers, lines, and rubber in master cylinders could all be shot.  Coolant, oil, those are obvious...hopefully the sprag/starter clutch thingy isn't locked up, (again there are fixes on here for those)  Water pump, hopefully not gummed up...brake light switch, starter switch can go bad (although not from sitting I wouldn't think)  Bearings in the steering 'neck'....I better stop. 

Shoot, am I ruining your plan?  I don't mean too...I replaced an entire frame for one of these (it was wrecked), fork seals/bushings, triple tree, all bent...and I got it going like it was near new  (ofcourse it only had 14k miles on it, so I figured it was worth re-building)  Make sure it runs first before tearing into brakes, etc.  check tranny, final drive unit, if those are ok, most everything else can be replaced, there is a great many used parts online for these.

It would be a fun project for sure, it looks like a decent bike once cleaned up...best of luck!

Sorry i left everything kinda opened ended! the bike is in decent shape, it has 88k miles on it. I Have heard it run before. I took my new fuel pump put it in a gas tank and fed it power and ran the gas line and the bike fired right up and sounded good! Like i said ive been riding dirt bikes since i was 4 so ive been riding for 18 years now haha im not afraid of turning wrenches but i dont want to dump a lot of money into this thing! 

Not trying to make anyone look foolish with this question but, how are you testing for power that makes you think you aren't getting it thru the sending unit.
The fuel pump only gets power(via the fuel pump relay in the electrical box under the fuel tank) when the engine is turning. There is no "pre-charge" time to run the fuel pump when you turn the key on.

Agree with 552255 that most likely all rubber bits, hoses, seals, vac lines, etc....will need/or seriously should be replaced just solely based on age alone.

Not at all! I checked the sending unit, where the wires go through the tank 3 of the 4 are good, i tested them for resistance. The 4th, the ground im assuming doesnt have resistance obviously meaning its not going though the sending unit part. I might have the wrong man. its the part that screws into the bottom of the tank where the lines and wires run through. there are 4 sodered wires.

Pretty much i guess im asking is there a way to fix that so i can get it to work or am i screwed?

Given the overall good yet dusty look of the bike in your photos, and the fact that it has a custom seat, rear rack and shock upgrade, I'd guess the bike was likely well-cared for, at least at some point.

If it's got <100k miles on it and you're employed it's probably worth your time to get it back on the road.

As far as i know the bike was taken pretty good care of. The guy who had it before me use to buy wrecked BMW bikes and fix them and sell them. He knows his stuff, thankfully this wasnt a wrecked one. But either way its not running haha it has 88k on it so i dont wanna put to much into it. Im at around $400 with little things i know tires and brakes are normal so that stuff doesnt count.

As stated above the clutch and trans all seem to be in good working order. on the center stand the clutch engages fine and tranny shifts smoothly, granted the bike isnt running but still a good sign. Its got a new clutch cable on it since my dad drop the old one when he pulled the clutch with the kickstand down and it broke haha

In my opinion this bike is way over complicated, i dont know why BMW does so much stuff that they do not need to. Im a huge Honda guy haha (not their cars though) haha

Really appreciate all the replies guys! hopefully with your help i can get it running soon!  :clap:

[Scott_]

Yea, if you have checked the individual wires where they pass thru the sending unit base and don't have continuity on the brown wire(ground is brown on these bikes btw) then you will probably be looking to need a replacement sending unit assy,,,, however.......
If you do a search here, I think that RBM had a post about pulling the sending unit out of the tank and doing some further diagnostics on it before you totally give it the kiss of death and toss it.

[rbm]

Tutorial on testing and reconditioning the Fuel Sending Unit

Ground is connected to the body of the sender via a spot-welded tab near the cable entrance.  If you have a defective ground connection, you could replace the ground with a separate wire tied under one of the sender mounting bolts.

[spokes]

Yea, if you have checked the individual wires where they pass thru the sending unit base and don't have continuity on the brown wire(ground is brown on these bikes btw) then you will probably be looking to need a replacement sending unit assy,,,, however.......
If you do a search here, I think that RBM had a post about pulling the sending unit out of the tank and doing some further diagnostics on it before you totally give it the kiss of death and toss it.

Ok thanks!

Tutorial on testing and reconditioning the Fuel Sending Unit

Ground is connected to the body of the sender via a spot-welded tab near the cable entrance.  If you have a defective ground connection, you could replace the ground with a separate wire tied under one of the sender mounting bolts.

That is what i did before i came on the site lol So i guess like i thought my sending unit is fried. does anyone know where i can get another one?! 99.9% sure that is the only reason i cant get the bike running. if i cant find one im just going to wire up an electric pump outside the tank.

[Motorhobo]

In my opinion this bike is way over complicated[\quote]

Go look at a newer BMW or any newer bike for that matter -- this thirty year old technology is a Fisher-Price toy by comparison. And still ranks performance wise with the best of them.

Good looking bike -- clean it up, put aside some cash and time to fix things as needed or preventatively based on likelihood of failure...your Honda days might be over  :2thumbup:

[spokes]

In my opinion this bike is way over complicated[\quote]

Go look at a newer BMW or any newer bike for that matter -- this thirty year old technology is a Fisher-Price toy by comparison. And still ranks performance wise with the best of them.

Good looking bike -- clean it up, put aside some cash and time to fix things as needed or preventatively based on likelihood of failure...your Honda days might be over  :2thumbup:

lol my dad is a bmw guy and so are most of his buddies. Dont get me wrong i like them i just think some stuff is stupid haha

anyone know where i can get a sending unit?  :dunno2:

[rbm]

http://www.ebay.de/itm/Benzinstandgeber-BMW-K1100LT-/301246530918?pt=DE_Motorradteile&hash=item4623b14566

[spokes]

http://www.ebay.de/itm/Benzinstandgeber-BMW-K1100LT-/301246530918?pt=DE_Motorradteile&hash=item4623b14566

Can you translate that into English somehow? Says 1100, will it work on my k75? Thanks!

[rbm]

Can you translate that into English somehow? Says 1100, will it work on my k75? Thanks!

Google translate through Chrome is your friend.  Take the URL and paste it into the form input on translate.google.com; it will open the page translated into the language of your choice. 

The fuel sender is the same for all K-bikes from about 1986 until the introduction of the K1200.  The sender changed for the K1200 models and beyond.  This one will fit your K75 and it is a good price as well.

[spokes]

Can you translate that into English somehow? Says 1100, will it work on my k75? Thanks!

Google translate through Chrome is your friend.  Take the URL and paste it into the form input on translate.google.com; it will open the page translated into the language of your choice. 

The fuel sender is the same for all K-bikes from about 1986 until the introduction of the K1200.  The sender changed for the K1200 models and beyond.  This one will fit your K75 and it is a good price as well.

Great thanks! I sent them an email. Hopefully I can get it and get the bike running!