BMW K bikes (Bricks)

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1Back to top Go down   K75 issue Empty K75 issue on Tue Mar 03, 2020 2:53 am

MikeisonTV

MikeisonTV
Silver member
Silver member
So I have a friend who dropped off her k75 café conversion. It fires no problem and will idle though it sounds weak compared to my K100 (also a cafe).

The issue is as soon as I touch the throttle it will die.

Having combed through mine with you guys help over the years, I started with the obvious, fuel pump and fuel filter. I figured the fastest way to rule these out would be to swap hers with my tank. I did, same thing. That rules out the fuel pump, filter, and lines inside the tank. There aren’t any vacuum leaks (no cracks in the hose or vacuum caps.

I just pulled the injectors to test them next. 


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Yep! I'm flipping through the air....that ain't good.
    

2Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 3:04 am

MikeisonTV

MikeisonTV
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Does this apply to this situation?
K75 issue Cf3d1510


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Yep! I'm flipping through the air....that ain't good.
    

3Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 3:18 am

MikeisonTV

MikeisonTV
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Silver member
And this?K75 issue Abaf4810


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Yep! I'm flipping through the air....that ain't good.
    

4Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 5:03 am

Arlina

Arlina
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Start with checking the fuel pressure.
Bad temp sens gives too much fuel.


__________________________________________________
K75 issue Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde
    

5Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 5:25 am

92KK 84WW Olaf

92KK 84WW Olaf
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@MikeisonTV wrote:And this?K75 issue Abaf4810
Getting the sensor off means taking off the radiator. But if you have a spare good one you could plug that in [the connector is accessible] and earth it against the engine block to try it out.


__________________________________________________
1992 K100LT 0193214 Bertha Alaska Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 103,800 miles
1983 K100RS 0011171 Fricka 606 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

6Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 6:14 am

duck

duck
Life time member
Life time member
If you think that it idles weakly then pull/inspect the spark plugs.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

7Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 12:50 pm

MikeisonTV

MikeisonTV
Silver member
Silver member
Is there a way to test the Fuel pressure regulator? Should this dirty throttle body be a concern that would play here? (Green circle)

Can I access the temp sensor by the removed air box as seen here? Not sure what it looks like and realoem.com doesn’t pull up the sensor on a search. Any one have a location of it?K75 issue 29251d10


__________________________________________________
Yep! I'm flipping through the air....that ain't good.
    

8Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 1:08 pm

duck

duck
Life time member
Life time member
K75 issue PFgv6Ys


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

9Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 7:07 pm

indian036

indian036
Life time member
Life time member
@MikeisonTV wrote:Is there a way to test the Fuel pressure regulator? 
Testing the Fuel Pressure Regulator is by seeing if it maintains the pressure it should. Insert a tee piece between the tank outlet and the fuel rail and attach a pressure gauge to the tee side outlet. (You can also do this between the fuel rail and the FPR, but its harder to get at.)

With engine running, it should read about 36psi, with small variations as throttle is opened or closed due to the vacuum line going to the FPR.

If the engine isn't running, when you push the starter button the pump activates and you should see your 36psi. Worst case scenario, you might have to press the starter twice, but if it doesn't get up to 36psi on one press there are questions to be answered. Without a running engine, you won't see the minor variation on throttle change.

Ideally, after the engine is turned off or the pressure has been correct on a starter button press, the pressure should be maintained for a significant time.

Bill


__________________________________________________
1985 K100RT  VIN 0028991  My original Very Happy   (Historic rego)
1985 K100RT  VIN 0029036  BOB the Blue Old Bike  (Historic rego)
1990 K100LT  VIN 0190452  Work in progress
1984 K100RT  VIN 0023022  Work needing lots of progress

1986 K100RT  VIN 0090542  Work needing lots and lots of progress
1993 K1100LT  VIN 0183046  Work in progress
1993 K75S  VIN 0213045  Newest toy, slightly non-original
    

10Back to top Go down   K75 issue Empty Re: K75 issue on Tue Mar 03, 2020 7:49 pm

Laitch

Laitch
Life time member
Life time member
@MikeisonTV wrote: I started with the obvious, fuel pump and fuel filter. I figured the fastest way to rule these out would be to swap hers with my tank. I did, same thing. That rules out the fuel pump, filter, and lines inside the tank. There aren’t any vacuum leaks (no cracks in the hose or vacuum caps.
How did swapping your filter and pump into her moto's tank—or swapping your tank with her tank—rule out defective lines in her moto's tank? Did you swap the hoses, too?

Which vacuum hose has no cracks—the fuel pressure regulator vacuum hose or the crankcase z-hose?


__________________________________________________
1995 K75 73,000 miles
K75 issue Usa-lo10
    

11Back to top Go down   K75 issue Empty Re: K75 issue on Thu Mar 05, 2020 1:50 am

volador

volador
Life time member
Life time member
That crankcase breather hose does not look correctly seated at the plenum chamber port, does not look like a OE hose

Looks like a crack in the rear of #2 throttle body rubber bushing under/inline with the "518" on plenum box


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1984 K100RS  1991 K100RS  Reap The Wild Wind... Ever Commute Is An Adventure
    

12Back to top Go down   K75 issue Empty Re: K75 issue on Fri Mar 06, 2020 2:41 pm

MikeisonTV

MikeisonTV
Silver member
Silver member
@volador wrote:That crankcase breather hose does not look correctly seated at the plenum chamber port, does not look like a OE hose

Looks like a crack in the rear of #2 throttle body rubber bushing under/inline with the "518" on plenum box?
This!
K75 issue Ec296c10

I found this hose coming off the crankcase that I think is supposed to run to the bottom of the tank. It is screwed closed.
K75 issue 5eaea310



Last edited by MikeisonTV on Fri Mar 06, 2020 5:58 pm; edited 1 time in total


__________________________________________________
Yep! I'm flipping through the air....that ain't good.
    

13Back to top Go down   K75 issue Empty Re: K75 issue on Fri Mar 06, 2020 3:13 pm

MikeisonTV

MikeisonTV
Silver member
Silver member
@Laitch wrote:
@MikeisonTV wrote: I started with the obvious, fuel pump and fuel filter. I figured the fastest way to rule these out would be to swap hers with my tank. I did, same thing. That rules out the fuel pump, filter, and lines inside the tank. There aren’t any vacuum leaks (no cracks in the hose or vacuum caps.
How did swapping your filter and pump into her moto's tank—or swapping your tank with her tank—rule out defective lines in her moto's tank? Did you swap the hoses, too?

Which vacuum hose has no cracks—the fuel pressure regulator vacuum hose or the crankcase z-hose?
I switched my entire tank and outside fuel lines. I thought doing this would isolate the fuel problem as I assumed it was fuel filter, or pump, or line in-between without taking apart 2 systems twice. Just a time saving move on my end.


__________________________________________________
Yep! I'm flipping through the air....that ain't good.
    

14Back to top Go down   K75 issue Empty Re: K75 issue on Sat Mar 07, 2020 6:09 am

duck

duck
Life time member
Life time member
Don't worry about this. It's fine with a screw in it.  The reason it is there is to vent fumes from the tank to the block.  It's CA emissions crap that keeps ten molecules of gasoline from venting to the atmosphere.

K75 issue 5eaea310


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

15Back to top Go down   K75 issue Empty Re: K75 issue on Thu May 21, 2020 11:51 pm

MikeisonTV

MikeisonTV
Silver member
Silver member
Meant to report that k75 got sorted and “runs better than it ever has!” The owner was so thankful to have her bike smooth and performing. So thank you guys for all the input


__________________________________________________
Yep! I'm flipping through the air....that ain't good.
    

16Back to top Go down   K75 issue Empty Re: K75 issue on Fri May 22, 2020 5:52 am

Laitch

Laitch
Life time member
Life time member
@MikeisonTV wrote:Meant to report that k75 got sorted and “runs better than it ever has!”
What was the remedy?


__________________________________________________
1995 K75 73,000 miles
K75 issue Usa-lo10
    

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