BMW K bikes (Bricks)


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1Back to top Go down   '85 K100rs Empty '85 K100rs 18/05/23, 10:05 pm

TimK100

TimK100
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Last  fall just before I was going to put it away for the winter it stalled  out on me . I pulled it off the road and tried to restart it, but no luck. I know that sometimes low voltage can cause issues with the electrical signals, so I went back later and charged it up and gave it another shot. It would crank and crank, maybe sputter a little and finally I got it going, but had to keep the engine really revving or it would stall out. I got it home and figured I would wait until spring, maybe it would sort itself out after a little rest. No such luck! After messing with it the last couple of days, this is what I know at this point: I can hear the pump kicking on for a second or two when I hit the starter. I pulled the fuel hose off the fuel rail and hit the button, some gas came pouring out. I re-connected it and pulled the fuel rail off with the injectors and gave it a shot - this only resulted in a small stream from each of the injectors. I've checked this before on a different bike and I have seen the spray that should have come out when I hit the button. So I tested the fuel pressure with a gauge this afternoon and got about 18 psi. Does this mean that the fuel pressure regulator is bad, or could there be other causes for this?   I really appreciate your guys knowledge on these frustrating issues. Sincerely, Tim

    

2Back to top Go down   '85 K100rs Empty Re: '85 K100rs 18/05/23, 10:18 pm

jbt

jbt
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It's not the fuel pressure regulator who causes low pressure: if it fails, it would give too much pressure.
It's more probably a leaking hose into the tank.
Nothing unusual after winter storage...
Look what I found yesterday in my K75 tank after 6 months storage:
'85 K100rs Tuyau_10
the left hose is the new one.
The right one was changed in July 2022. It's now 20% oversized and the external layer is like chewing gum. It can be torn with no effort and, indeed, self destructed itself into the tank: ou can see the core. It's leaking, naturally...
Thanks ethanol.

If there's a leak here, between the pump and the rigid hose into the tank, it may remain unseen if you're not watching into the tank, motor running, with a low level of fuel. It will give sometimes enough pressure to start and idle, but the engine dies if you open the throttle...


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

3Back to top Go down   '85 K100rs Empty Re: '85 K100rs 18/05/23, 10:25 pm

TimK100

TimK100
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I can't get it to start and idle. The fuel pump is in the tank, are you saying that I should check the fuel hoses in the tank? I did not think of that.
Thanks

    

4Back to top Go down   '85 K100rs Empty Re: '85 K100rs 18/05/23, 10:44 pm

Point-Seven-five

Point-Seven-five
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A clogged fuel filter will cause low pressure.  Replace it while you're in there.


__________________________________________________
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
    

5Back to top Go down   '85 K100rs Empty Re: '85 K100rs 18/05/23, 11:09 pm

TimK100

TimK100
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Thank you, I do have an extra and its definitely worth doing while I'm in there

    

6Back to top Go down   '85 K100rs Empty Re: '85 K100rs 19/05/23, 10:51 am

92KK 84WW Olaf

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Check the fine mesh basket under the fuel pump. Mine was clogged up and caused a similar issue. Due to age of the bike I did replace the entire of the stuff in the tank as I had them in the shed. As in pump, filter basket, mount, damper, fuel filter and in tank hoses. I managed to run the tank down and get 20.40 litres in one day so i know all is good.

If your tank is bolted down look at the plug connector into the front left of the tank. Its a known break down issue. I got replacements from www.tills.de for very small money.

In tank hoses should be marked NBR/NBR. Outside tank hoses are not suitable for use insdide the tank as they are only fuel and ethanol resistant on the inside surfaces


__________________________________________________
1992 K100LT 0193214 Bertha 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 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 49,200 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

7Back to top Go down   '85 K100rs Empty Re: '85 K100rs 22/05/23, 02:07 am

TimK100

TimK100
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active member
I was able to get into the tank and look everything over last week. The lines themselves looked in very good condition. I pulled the pump and checked the screen underneath- it didn't look bad, but I cleaned it anyway. I pulled out the fuel filter and tried to blow through it - sure enough, I think I found my problem. It was clearly obstructed. After examining inside the rest of the tank, I noticed some sediment at the lower edges. I felt around and it seemed very gel like. It might be old Stabil from previous owners, as I have never used it. I dumped the tank and let it dry over the weekend. Early this week I should have some time to put it back together. Fingers crossed.

    

8Back to top Go down   '85 K100rs Empty Re: '85 K100rs 22/05/23, 02:34 am

duck

duck
Life time member
Life time member
Fuel filter: NAPA 3032


__________________________________________________
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
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   '85 K100rs Empty Re: '85 K100rs 22/05/23, 03:27 am

Laitch

Laitch
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TimK100 wrote:I felt around and it seemed very gel like. It might be old Stabil from previous owners, as I have never used it.
That wasn't "old Stabil". That was gum, varnish and other residue created when gasoline that hasn't been used soon enough becomes water-saturated to form two layers; gasoline of less octane than the original fuel is the upper layer. Gum, varnish, corrosion precipitates and water comprise the lower layer. When enough of that mess gets sucked into the fuel system, it eventually clogs fuel filters, fuel injectors and fuel hoses. Properly used, Stabil and other fuel stabilizers are intended to inhibit that process, but their effectiveness generally is limited to one year and they won't dissolve crud already created in the tank by failure to use fuel soon enough.

    

10Back to top Go down   '85 K100rs Empty Re: '85 K100rs 23/05/23, 12:45 am

TimK100

TimK100
active member
active member
Thank you Laitch, that is very interesting, and I' never heard of that. I got it back together today, put some fresh fuel in it, and gave it a go. It cranked quite a bit, but did fire up. Sounded a little rough at first, but then it smoothed out. Took it for a short ride and it ran like a champ. Now I just need to spend  some time getting the rest of the plastics back on and put some miles on. Thanks again everybody

    

11Back to top Go down   '85 K100rs Empty Re: '85 K100rs 23/05/23, 09:15 am

92KK 84WW Olaf

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Running a K with 10% diesel in the gas tank occasionally is amazingly effective at cleaning out the system. Amazing the things you find out. It runs fine too apart from a little white smoke.


__________________________________________________
1992 K100LT 0193214 Bertha 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 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 49,200 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

12Back to top Go down   '85 K100rs Empty Re: '85 K100rs 23/05/23, 11:58 am

duck

duck
Life time member
Life time member
92KK 84WW Olaf wrote:Running a K with 10% diesel in the gas tank occasionally is amazingly effective at cleaning out the system. Amazing the things you find out. It runs fine too apart from a little white smoke.

Please explain how diesel fuel cleans anything in a gasoline engine. It's generally accepted that running diesel fuel in a gasoline fuel system clogs the fuel filter and injectors as well as fouling spark plugs.

An additive specifically formulated to clean a gasoline fuel system might be a better idea.


__________________________________________________
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
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
    

13Back to top Go down   '85 K100rs Empty Re: '85 K100rs 23/05/23, 03:17 pm

Laitch

Laitch
Life time member
Life time member
duck wrote:An additive specifically formulated to clean a gasoline fuel system might be a better idea.
It might be, but it's from the same bag of tricks that produces diesel. Lucas Fuel Treatment, Amsoil Upper Cylinder Gas Treatment, Marvel Mystery Oil and Gawdnosewhatelse out there contain paraffinics which are major constituents of diesel. Kerosene is a paraffinic. Biodiesel and these treatments contain hydrotreated parafifnics. Hydrotreatment and hydrogenated seem to be interchangeable descriptors for similar processes, and hydrogenated vegetable oil is foundation of biodiesel.

In the low compression auto engines of my youth, diesel was trickled into carburetors of running engines with the hope that it would lubricate throttle plates, and dislodge carbon particles surrounding jets and within other secret passages by means of smoke, heat and pressure. The process manifest itself similarly to smoke cleansing ceremonies found worldwide and was accompanied by the usual expectation of well-being to follow. Volumes of fragrant smoke filled the atmosphere with a palpable sense of accomplishment at a low level of effort. The oil constituents may have lubricated pushrod and valve assemblies, too. The results were variable, but the panacea-effect, and bourbon, tended usually to lift the mood.

It's touching that similar stuff is still being used in the technology-laden environs of today. If these ubiquitous hydrotreated paraffinics were befouling fuel injectors and sickening today's engines in pandemic proportion, we likely wouldn't still be seeing these compounds proliferate in the marketplace. Low-cost hope is always attractive. Smile 

I have since learned that riding hell out of my Brick is better than rendering it as a fuel storage container that will need eventual chemical intervention in a desperate attempt to restore its intended purpose.

    

14Back to top Go down   '85 K100rs Empty Re: '85 K100rs 02/07/23, 02:50 am

TimK100

TimK100
active member
active member
After riding it around a couple of times, it didn't seem like I was quite getting the full power or acceleration it should have. I watched a couple of videos on the fuel injector spray patterns to get an idea of what they should look like. So I pulled the fuel rail with the injectors connected and gave the ignition a few hits, and it did seem like they weren't all firing the same. I removed the injectors and sent them to Mr. Injector in Idaho who cleans and tests them. At about $25 per injector I thought this seemed like a relatively inexpensive next step. When I got them back and put them in I took it for a ride, and there it was, the power and acceleration I was used to. 

Thanks again for all of the input from everybody, this website is the best tool to have in your bag - I have recommended it to anybody I come across with troubling issues they may be having.    Cheers everybody!

    

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