BMW K bikes (Bricks)


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1Back to top Go down   Stalling after starting Empty Stalling after starting Tue May 16, 2023 12:57 pm

boomhour

boomhour
active member
active member
I am just starting to run and test a bike after full teardown and rebuild (did not separate the head from the block).  Everything you can replace was replaced by me or the previous owner within the last few years.  I got it running yesterday for the first time and rode it around to test things out and get a feel for things.  It ran ok and would idle at stops but the acceleration was lagging and then when I hit higher RPM's it would have more power.  with the timing light I set the timing to about 6-8 degrees counter clockwise of default alignment. That seems opposite of what I've read here but that's how I got the bike to run.  After my 20 minutes test rides I started fiddling with the timing and that when things went south.  Oh, and I also ran it out of fuel but was luckly within a block of the garage.   Mad

today, I got some fuel and tried again.  I can get it to start but it usually dies within 2-10 seconds after starting.  I had it going down the road for a minute and it was lurching a lot.  

It ran fine before tear down in August of 2022 and it ran well enough yesterday, but not good enough to be happy with it.  I've not touched the the regulator or air flow meter screw.  

previous owner had an issue with the fuel system enought that he installed a pressure valve inline with the return line and ended up replacing the fuel regulator.  Fixed his issue but as far as i can tell the regulator is only a couple years old. 

temp sensor, injectors, plugs, wires are all new. 

Where should I start with diagnosing this?  
  1. dry the plugs
  2. buy a HES tester
  3. replace the regulator....again

    

2Back to top Go down   Stalling after starting Empty Re: Stalling after starting Tue May 16, 2023 1:21 pm

Laitch

Laitch
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Life time member
You should return the timing alignment to its specified marks to get this sorted. You should verify that the ignition wires are firmly connected to the correct coils, and the plug wires are firmly seated on the plug terminal nuts—no wobble. You should verify all hoses in the fuel tank are firmly connected and the fuel filter is correctly oriented.

Did you replace the z-hose and the rubber intake manifolds, as you seem to have indicated?

    

3Back to top Go down   Stalling after starting Empty Re: Stalling after starting Tue May 16, 2023 1:33 pm

boomhour

boomhour
active member
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Laitch wrote:You should return the timing alignment to its specified marks to get this sorted. You should verify that the ignition wires are firmly connected to the correct coils, and the plug wires are firmly seated on the plug terminal nuts—no wobble. You should verify all hoses in the fuel tank are firmly connected and the fuel filter is correctly oriented.

Did you replace the z-hose and the rubber intake manifolds, as you seem to have indicated?
Yes, the Z hose was replaced and the manifolds are new and have been installed with black RVT gasket maker. 

all the electrical and plug wires are seated and firmly connected to the coils.  wires are firmly seated on the plug nuts.  all these systems have been previously checked with a mulit meter. They appear to be in spec or new.

    

4Back to top Go down   Stalling after starting Empty Re: Stalling after starting Tue May 16, 2023 1:38 pm

boomhour

boomhour
active member
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boomhour wrote:
Laitch wrote:You should return the timing alignment to its specified marks to get this sorted. You should verify that the ignition wires are firmly connected to the correct coils, and the plug wires are firmly seated on the plug terminal nuts—no wobble. You should verify all hoses in the fuel tank are firmly connected and the fuel filter is correctly oriented.

Did you replace the z-hose and the rubber intake manifolds, as you seem to have indicated?
Yes, the Z hose was replaced and the manifolds are new and have been installed with black RVT gasket maker. 

all the electrical and plug wires are seated and firmly connected to the coils.  wires are firmly seated on the plug nuts.  all these systems have been previously checked with a mulit meter. They appear to be in spec or new.
pulled a plug just now and it's covered in black soot.

    

5Back to top Go down   Stalling after starting Empty still not running.... Wed May 17, 2023 11:52 am

boomhour

boomhour
active member
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as the heading indicates the bike is turning over but not starting.  
  1. i've pulled all the spark plugs and gave them a wire brushing to remove the soot.
  2. i checked the TPS and it's set to ohm 0 with the throttle closed.
  3. I removed the gas cap and with the fuel pump running can see fuel returning to the tank.
  4. throttle cable has a small amount of slack but tightens just as I start to twist the throttle. 
  5. idle screw is not pushing on the throttle bodies.
  6. fuel injection control unit plug is seated. 
  7. i installed the carb sync and set the timing with a light.  this is what I don't understand.  the timing mark alignment is aligned when the HES is turned several degrees counter clockwise from the window.  here is the an imageStalling after starting Timing10

Can you set the timing by just cranking the engine over?

not sure what to try next.  could the HES be causing the issue?

    

6Back to top Go down   Stalling after starting Empty Re: Stalling after starting Wed May 17, 2023 12:27 pm

jbt

jbt
Life time member
Life time member
I'll replace the inside hoses in the tank.
This symptom is usually associated with a leak of pressure: it allows to start and run but not to maintain enough pressure to rev.
Here's two I've changed yesterday:
Stalling after starting Tuyau_10
The new one is left.
The previous one is right: I had changed it in july 2021 during a trip in Spain!
Size +20%; external layer is as soft as peanut butter, and the hole let us see the core of the hose. Leaking, of course.
Thanks ethanol...Yet I never use fuel with more than 5 percent of that crap inside.
But the bike remains 6 month stored with fuel in tank.


__________________________________________________
Let us enjoy the transient delight
That fills our fairest day.
    

7Back to top Go down   Stalling after starting Empty Re: Stalling after starting Wed May 17, 2023 1:01 pm

boomhour

boomhour
active member
active member
jbt wrote:I'll replace the inside hoses in the tank.
This symptom is usually associated with a leak of pressure: it allows to start and run but not to maintain enough pressure to rev.
Here's two I've changed yesterday:
Stalling after starting Tuyau_10
The new one is left.
The previous one is right: I had changed it in july 2021 during a trip in Spain!
Size +20%; external layer is as soft as peanut butter, and the hole let us see the core of the hose. Leaking, of course.
Thanks ethanol...Yet I never use fuel with more than 5 percent of that crap inside.
But the bike remains 6 month stored with fuel in tank.
hoses in tank are new and submersible type.

    

8Back to top Go down   Stalling after starting Empty Re: Stalling after starting Wed May 17, 2023 2:10 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
With the new lines in the tank are you absolutely sure the clamps are tight?  You wouldn't be the first owner to not get one of the clamps tight enough to prevent a leak at full system pressure.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

9Back to top Go down   Stalling after starting Empty Re: Stalling after starting Wed May 17, 2023 11:32 pm

boomhour

boomhour
active member
active member
Point-Seven-five wrote:With the new lines in the tank are you absolutely sure the clamps are tight?  You wouldn't be the first owner to not get one of the clamps tight enough to prevent a leak at full system pressure.
all the fuel lines have new fittings and have been tightened.

    

10Back to top Go down   Stalling after starting Empty Re: Stalling after starting Wed May 17, 2023 11:49 pm

Laitch

Laitch
Life time member
Life time member
jbt wrote:Here's two I've changed yesterday:
Stalling after starting Tuyau_10
The new one is left.
The previous one is right:
It seems to me that the hose on the right wasn't R10-rated submersible fuel injection hose, or whichever the rating for submersible fuel injection hose is in the EU. I've been using E10 ethanol-blend gasoline in my Brick exclusively for the 12 years I've owned it and never had R10 hose degrade at all, let alone like that. Maybe fuel in the USA is of better quality than Europe's, but I doubt that. Of course, I have only one moto and I ride hell out of it during the season so it always has fresh fuel; however, I store it for six months per year with a full tank of conditioned E10 and fuel separation has never been a problem either.

I think the problem with the hose on the right was its composition, not the fuel to which it was exposed. Does the replacement hose have a rating on it, jbt?

    

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