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1Back to top Go down   My mojo don't go Empty My mojo don't go Thu Oct 13, 2022 2:21 pm

Bluebeemer

Bluebeemer
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A classic tale, "it ran when I parked it!" That was last spring; it endured the summer heat, 100 deg Fahrenheit at times, evaporated almost an entire tank of gas. Now it starts and idles but will not take any throttle, it just dies when I try. 

I'm not very familiar with fuel injection, I can tune a set of webers within an inch of their lives, but what the hell is fuel injection.? I did have a euro spec BMW car, 635 which had in fact the same version injection as my bike, ran like a top. I do have some manuals to help me.  Anyway, prelim inspection suggests the fuel pump is not pumping adequately. Ignition on, voltage at the fuel pump plugin, four wires: two show 10.3 volts, one, maybe .1 volt and one no voltage. The pump is new. First step I'm taking is to check all the electrical connections related to running, clean and lube. As a new owner, it gives me a chance to see how everything is put together hands on, as it were. 

I've just about finished step one. I just removed the injection unit to clean and dielectric grease the contacts, put it all together. Next I plan to get into the tank and check out in there, in particular fuel filter and pump connections. If it all checks out, reinstall the tank and give it a test. If still not right, check fuel injection pressure at the fuel rail and furthermore test injectors.

 I am open to any and all suggestions about what may be wrong. I remember reading a post some months ago about the fact that the K motor will run without a functioning fuel pump using just gravity feed from the tank; is that what's going on in my case?

    

2Back to top Go down   My mojo don't go Empty Re: My mojo don't go Thu Oct 13, 2022 2:39 pm

duck

duck
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First thing I would do is pull the fuel filter out and blow through it. It it's clogged then get thee to NAPA and purchase a 3032 fuel filter.


__________________________________________________
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
    

3Back to top Go down   My mojo don't go Empty my mojo don't go Thu Oct 13, 2022 4:40 pm

Bluebeemer

Bluebeemer
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Duck, followed your advice, my step two, drained the tank, a tankful of bad gas and huge amount of crap on the bottom. I will flush it out with clean gas to make sure all the debris is out. Will pull out fuel filter and replace, do doubt it's bad.  We'll see!

    

4Back to top Go down   My mojo don't go Empty my mojo don't go Thu Oct 13, 2022 4:43 pm

Bluebeemer

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no doubt, it's bad!

    

5Back to top Go down   My mojo don't go Empty my mojo don't go Sat Oct 15, 2022 11:40 am

Bluebeemer

Bluebeemer
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As suggested by Duck, fuel filter was completely blocked and whatever fuel in there was brown. Flushed the tank out multiple times with fresh gas finding much particulate material, somewhat clear probably the result of an entire tank of gas being evaporated in the summer heat, close to a handful of crap so far. Not done yet, I'll keep flushing til no more stuff comes out. BTW, what exactly is one left with once the volatile part of gasoline evaporates? Would it dissolve with the introduction of fresh gas? Tks for all the help.

    

6Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Oct 15, 2022 12:02 pm

Laitch

Laitch
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Bluebeemer wrote: BTW, what exactly is one left with once the volatile part of gasoline evaporates? Would it dissolve with the introduction of fresh gas?
This is what is left, along with other substances like dissolved rubber from hoses and the pump's vibration damper and minerals deposited by water condensation

You could use white vinegar to clean that tank's interior and scrub off remaining residue with a scotchbrite pad on a flexible extension wherever you cannot reach with your hand alone.


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

7Back to top Go down   My mojo don't go Empty my mojo don't go Sat Oct 15, 2022 1:31 pm

Bluebeemer

Bluebeemer
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Still flushing the tank;(10 times) for the most part it is clean, but it seems that every time I flush with a quart of gas I get smallish chunks of brown gritty that appear to be gas deposits, not bits of extraneous debris. Do you think the fuel pump could also be clogged similar to the fuel filter. Should I remove it just to be certain. Maybe a screen under the pump is holding stuff. I'm content to continue to gas wash the tank til clean, but it would be nice to know the pump is ok. Looking in the tank it is pretty clean by any real standard but I cannot see underneath the pump bracket. Any thoughts on the subject?

    

8Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 1:58 am

Laitch

Laitch
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Bluebeemer wrote: Looking in the tank it is pretty clean by any real standard. Any thoughts on the subject?
To me, the realist standard would be no grit found in the rinse. Removing the pump, its pre-filter and its holder for inspection, replacing all interior hoses with new SAE30R10 hoses, verifying interior hoses are clamped to fittings with fuel injection hose clamps, and replacing all exterior hoses that could also be degraded by grit are other thoughts.


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

9Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 2:03 pm

92KK 84WW Olaf

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Laitch wrote:
Bluebeemer wrote: Looking in the tank it is pretty clean by any real standard. Any thoughts on the subject?
To me, the realist standard would be no grit found in the rinse. Removing the pump, its pre-filter and its holder for inspection, replacing all interior hoses with new SAE30R10 hoses, verifying interior hoses are clamped to fittings with fuel injection hose clamps, and replacing all exterior hoses that could also be degraded by grit are other thoughts.
I did that in my RS eaerlier this year, replaced everything in the tank [pump, basket, pump mounting, damper, in tank hoses, filter] and later replaced the external fuel lines and in the last two weeks replaced the injectors too. I siphoned the old fuel out of the tank and was able to pull almost all of the grit with it.

Another thing, get a service kit for the gas tank cap, there is a foam gasket inside the cap that deteriorates from the ethanol and lets water in. I swapped my cap out on the RS for the later one because it had an early push button one that lets water in. I noticed the later type letting water in too but saw the issue is the foam gasket. I took it apart to rekey it to the RS ignition and swapped out the seals and O rings in it while I was at it.

Its worth doing. Going to do the exact same in my RT.


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 49,840 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

10Back to top Go down   My mojo don't go Empty my mojo don't go Sun Oct 16, 2022 2:22 pm

Bluebeemer

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Good thorough advice! Took out the fuel pump, found more crap and parts that could stand replacing. Will order parts and start replacing hoses. They look ok but I have no idea about their history. Thanks for the comprehensive breakdown of R and R. I'll work to get the bike back together in the meantime, I gather I can work on the fuel tank still on the bike. Where and how is the best way to get the gas out without taking the tank off. Disconnecting the fuel output line at the fuel rail does not appear to drain out the fuel, maybe just turn on the ignition?

    

11Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 2:26 pm

duck

duck
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I'd pull the fuel pump out and jump 12V to it to see if it's working. The smaller diameter terminal in 12V, the larger terminal is ground.

It should spin and whir if it's working. If it sounds like it's "trying" but not spinning then here's a couple of things to try to revive it:

1) Jump it with polarity reversed for just a quick second. If crud is stuck in it then spinning it backwards momentarily may unstick it.

2) Soak it in concentrated fuel injector cleaner for a day or two. That has worked for me.


__________________________________________________
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
    

12Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 2:30 pm

duck

duck
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Bluebeemer wrote:Good thorough advice! Took out the fuel pump, found more crap and parts that could stand replacing. Will order parts and start replacing hoses. They look ok but I have no idea about their history. Thanks for the comprehensive breakdown of R and R. I'll work to get the bike back together in the meantime, I gather I can work on the fuel tank still on the bike. Where and how is the best way to get the gas out without taking the tank off. Disconnecting the fuel output line at the fuel rail does not appear to drain out the fuel, maybe just turn on the ignition?

Turning the ignition on won't help. The fuel pump only has power when starting or when the engine is running. You can hit the starter button to drain it from the fuel line that goes to the fuel rail but be careful not to kill your battery. Siphoning is my preferred method to get gas out.


__________________________________________________
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
    

13Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 3:12 pm

Laitch

Laitch
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Life time member
This siphon is simple to use and available at Walmart and many hardware stores.
My mojo don't go Scree215


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

14Back to top Go down   My mojo don't go Empty my mojo don't go Sun Oct 16, 2022 5:06 pm

Bluebeemer

Bluebeemer
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My mouth is well acquainted with overzealous siphoning technique; siphoning it is! Tks.

    

15Back to top Go down   My mojo don't go Empty My mojo don't go Sun Oct 16, 2022 5:14 pm

Bluebeemer

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Tks Duck; I thought to give it a spin while out of the tank, but did not. I can still test it tho. It's a new pump so I thought it would be ok never thinking it too could be thoroughly jammed up.

    

16Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sun Oct 16, 2022 6:19 pm

Laitch

Laitch
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Bluebeemer wrote:I swapped my cap out on the RS for the later one because it had an early push button one that lets water in. I noticed the later type letting water in too but saw the issue is the foam gasket.
Are the hinges of these caps at their forward sides or their rear sides?


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

17Back to top Go down   My mojo don't go Empty my mojo don't go Tue Oct 18, 2022 10:22 pm

Bluebeemer

Bluebeemer
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Duck was right. It was a 100 percent blocked fuel filter and a gas tank loaded with debris; tks for the help! Idle rpm now is too high, 1200  to 1500 on the tach. how do I adjust idle? Clymer manual is useless!

    

18Back to top Go down   My mojo don't go Empty Re: My mojo don't go Wed Oct 19, 2022 7:38 am

duck

duck
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Bluebeemer wrote: how do I adjust idle?

This screw on the bar near where the throttle cable is on the throttle bodies:

My mojo don't go XJ42U0w


__________________________________________________
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
    

19Back to top Go down   My mojo don't go Empty my mojo don't go Fri Oct 21, 2022 1:40 pm

Bluebeemer

Bluebeemer
active member
active member
Bike runs beautifully; even with the high idle. The bike runs better than when I bought it. FyI, the idle adjustment screw is not even touching the adjustment tab. I can push it down and the idle comes down. What I suspect is that the motor ran poorly so raising the idle perhaps helped. Now that the motor is running better, the idle is too high. I suspect the throttle cable was messed without knowing that idle was adjusted elsewhere. Any way that could have happened? 

When I had my Norton aka Notrun. It was a hoot to adjust the carbs so good, I could lower the idle as much as possible, down to hearing the individual cylinder firings; classic British sound as long as each firing was strong and healthy it could do it.

    

20Back to top Go down   My mojo don't go Empty Re: My mojo don't go Fri Oct 21, 2022 2:49 pm

duck

duck
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You can also adjust the throttle cable up at the throttle perch. Pull the boot off of the throttle cable (left side of brake fluid reservoir) and you'll see that that end of the cable is threaded with lock nut on it. Loosen the lock nut and screw the cable threads in to get more slack.


__________________________________________________
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
    

21Back to top Go down   My mojo don't go Empty my mojo don't go Fri Oct 21, 2022 6:10 pm

Bluebeemer

Bluebeemer
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Duck, found the throttle cable adjustment; loosened it a couple of turns; the idle still stays above 1K with both the throttle cable free and the adjustment screw backed off to not touching the rail, but drops only when I press on the adj screw.... to just under 1K. What should the idle number be? I assume under 1K is ok! It appears that it is not the throttle cable being too tight that is holding the idle up. I did have the injection intake boots replaced by Max BMW last fall as part of a general inspection service. I have no idea where to go next. Maybe a missing return spring?

    

22Back to top Go down   My mojo don't go Empty my mojo don't go Fri Oct 21, 2022 6:13 pm

Bluebeemer

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That's the bad news, the good news is that the bike runs great even with the elevated idle rpm.

    

23Back to top Go down   My mojo don't go Empty my mojo don't go Fri Oct 21, 2022 6:20 pm

Bluebeemer

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I guess I could live with the idle being above 1K. Only bothers me when I start out. BUT... is the question with no answer.

    

24Back to top Go down   My mojo don't go Empty Mojo Fri Oct 21, 2022 6:43 pm

daveyson

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Check that the hose clamps on the boots aren't interfering with movement.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

25Back to top Go down   My mojo don't go Empty Re: My mojo don't go Fri Oct 21, 2022 6:45 pm

duck

duck
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The other thing that can hold the throttle open is the TPS (Throttle Position Switch) at the back of the throttle bodies. Try loosening the screws for that and turning it a little.

The proper position for that is that you should hear a subtle click (you can't hear it with the engine running) right when the throttle starts to move off of idle.

Factory spec for idle is 950-1050. (I run my K75s at 1200ish though to mitigate the slight lag that K75s can have off the line.)


__________________________________________________
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
    

26Back to top Go down   My mojo don't go Empty my mojo don't go Sat Oct 22, 2022 1:27 pm

Bluebeemer

Bluebeemer
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Just thinking out loud: seems to me that the idle adjustment of any Infernal combustion engine  should have a range from too low to too high; mine is at present only too high. Tks for the suggestions. I will test them out. 

Manufacturers tend to favor a lean state of air to fuel ratio as it provides better emission results. Hot dogs and perhaps purists, tend to favor performance settings for the obvious reason which, in general, is a richer air to fuel ratio. With regard to idle settings, leaner tends to raise the idle and reduce performance punch. Richer lowers the idle but the engine runs better. This info is based on conventional carburation not fuel injection design, tho I suspect it is also true for fuel injection motors too. My take on idle rpm is that something lower than 1K should be right for any 4 cyl motor, possibly for any motor at all! Of course in the case of conventional carbs, where the low speed fuel circuit kicks in, rpm wise!

Of course, I do not think this is the particular problem in my case, but isn't there an adjustment capability on the air flow device to compensate for this? One would need the ability to read the exhaust emissions to precisely make changes, an expensive proposition at least for the DIY er. Any thougts on the subject? I apologize if all of this is old hat and already been thoroughly discussed.

    

27Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Oct 22, 2022 3:29 pm

duck

duck
Life time member
Life time member
Here's a method to adjust the MAF sensor w/o an exhaust gas analyzer:

https://pdfhost.io/v/9bFtrTAxp_Adjust_CO_MixtureK75K100Exhaust


__________________________________________________
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
    

28Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Oct 22, 2022 7:36 pm

Laitch

Laitch
Life time member
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Bluebeemer wrote:FyI, the idle adjustment screw is not even touching the adjustment tab. I can push it down and the idle comes down.
daveyson wrote:Check that the hose clamps on the boots aren't interfering with movement.


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

29Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Oct 22, 2022 8:37 pm

duck

duck
Life time member
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Laitch wrote:
Bluebeemer wrote:FyI, the idle adjustment screw is not even touching the adjustment tab. I can push it down and the idle comes down.
daveyson wrote:Check that the hose clamps on the boots aren't interfering with movement.

He mentioned getting the TB intake boots replaced at Max BMW. My impression of Max is that they're more competent than most dealers which begs the question: How was it idling when you got it back from Max?

If it idled well after the Max service then the TB boot clamps probably aren't interfering with throttle return.

Here's where the boot clamps go on a K75. K100 should be the same with 1, 2 & 3 looking like 1 & 2 here with the rearward one turned CW a bit:
My mojo don't go K75pa.ab.tb.59.tbbootclamppositions

The reason that I mentioned the TPS is that I had a K75 once that would idle way too high after I rehabbed it. Took me a while but eventually discovered that I had knocked the TPS out of position and that that's what was holding the throttle open.


__________________________________________________
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
    

30Back to top Go down   My mojo don't go Empty Mojo Sun Oct 23, 2022 2:35 am

daveyson

daveyson
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Another thing, check the accelerator cable linkages, quadrant and stuff for lubrication, and the cable itself, maybe by disconnecting it at the bottom. The cable lubricant  needs to be special stuff for Teflon.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

31Back to top Go down   My mojo don't go Empty my mojo don't go Fri Nov 04, 2022 9:22 pm

Bluebeemer

Bluebeemer
active member
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Tks for all the suggestions. I have not had the time to check any further on the high idle issue. The idle increase came about once I did a major clean of the fuel tank and replaced the fuel filter, totally blocked. Additionally I did a thorough clean and dielectric lube of all the connectors under the tank, relays in the relay box, and major injection control unit.s But, before all that the idle was passable, even before I sent the bike up to Max for service. I suspect the summer heat, 90's plus, evaporated an entire tank of fuel leaving behind all sorts of additional sludge that closed off the fuel filter, maybe the pump too. I think the problem was present before I bought the bike and only got worse as time went on and went over the top when I tried to ride the bike this fall. Once the tank was thoroughly cleaned, the motor really perked up, but not having anything to compare to, I thought the motor had been doing ok. 
Max did a valve check, timing ck too and replaced the injection boots. Did they do the boot clamps right or a throttle valve balance, I don't know. Considering the lack of service history, I'm at a loss at what may or may not be an issue. 

For the moment, I'll use the reference pic to ID the boot clamps and make sure throttle movement is not limited. Years ago, one could adjust air flow on multiple carbs listening with a steth or even just a rubber tube placed in the carb intakes. I wonder if a stethoscope would be sensitive enough to use on the K motor to measure air flow? I certainly can see that an uninformed mechanic may have messed with the air screws to get the motor to run better. Tks again fo all the suggestions and and help. I'll keep in touch as I make progress.

    

32Back to top Go down   My mojo don't go Empty my mojo don't go Sat Nov 05, 2022 3:14 pm

Bluebeemer

Bluebeemer
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On going saga. TPS seems to be ok, clicks as soon as the throttle slack is removed. Whilst checking clamp positions at throttle valve connection to intake manifold/cylinder head. They appear to be correctly positioned tho I could not verify all 4 of them. Then I noticed a 4 inch length of new 1/4 hose seeming to be pinched. I unpunched it and to my surprise an unattached end appeared. Tracing it back it disappears around the front of the engine and reappears under the air box, It attaches to some kind of wired electrical sensor. I'm thinking air leak, not under there but back at the fuel rail tho I see no place to plug the hose in. Am I on to something?

    

33Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Nov 05, 2022 4:27 pm

Laitch

Laitch
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Bluebeemer wrote: Tracing it back it disappears around the front of the engine and reappears under the air box, It attaches to some kind of wired electrical sensor. I'm thinking air leak, not under there but back at the fuel rail tho I see no place to plug the hose in. Am I on to something?
It would probably be helpful to include photos with your descriptive gymnastics. The switch is likely the vacuum switch. The hose connects a port on the #1 throttle body to a port on the switch. It was discontinued in later models.

Read about it here and view a drawing of it and its location in the Troubleshooting the EFI document linked in the Tech Page accessed in the Portal.  If that's it and you decide to subscribe to the widely accepted opinion that the switch does little or nothing, remove the hose, cap the port, tape the wire terminals and call it a day.


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

34Back to top Go down   My mojo don't go Empty Re: My mojo don't go Sat Nov 05, 2022 4:41 pm

duck

duck
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Bluebeemer wrote:On going saga. TPS seems to be ok, clicks as soon as the throttle slack is removed. 

It can still be holding the throttle open if it's not positioned correctly.


__________________________________________________
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
    

35Back to top Go down   My mojo don't go Empty my mojo don't go Sat Nov 05, 2022 4:48 pm

Bluebeemer

Bluebeemer
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Tks, Duck; I'll look into Clymer on positioning the sensor. I guess it could be off by only a few degrees and raise the idle.

    

36Back to top Go down   My mojo don't go Empty my mojo don't go Mon Nov 07, 2022 7:33 pm

Bluebeemer

Bluebeemer
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active member
As per Duck's advice, I removed the TPS, found a broken O-ring which I replaced. Other than that nothing else caught my attention. I suspect it was once replaced in the bikes lifetime, It was a press on setup with the throttle shaft having a flat to prevent movement of the TPS relative to the throttle shaft. The O-ring replacement made a small difference in the motor's output. Idle speed is consistently just under 1500 rpm according the the tach and running pretty nicely notwithstanding the high revs. Maybe I should just give it up!

One thing I did notice looking at the idle adjustment mechanism, the gap between the adjustment screw and the tab it adjusts against is quite large. I think even if it were fully screwed in, it would not close the gap; it's as if something were missing maybe. I can't take a pic of the gap but I might be able to measure it roughly. Also, as I already said, the throttle valves seem to close somewhat softly. In my experience when a throttle closes it usually does so with some direct sense of a "mechanical stop effect," with certainty. I just don't know these motors well enough to say what's right and what's wrong. Having said that, I'm not certain that there isn't some rubber in the way preventing the idle from lowering. The injection boot clamps appear to be positioned right and knowing that BMW Max did the repair, I'm inclined to think that's not the problem. You can't see squat with the air box where it is. I would hate to think about removing it to confirm the boot clamps are right. What's next Jack!!

    

37Back to top Go down   My mojo don't go Empty Re: My mojo don't go Mon Nov 07, 2022 7:53 pm

Laitch

Laitch
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Remove the cover of the throttle gear and chain assembly to determine if there isn't dried, caked grease fouling up the movement of the gear in there. The throttle should snap back when it's twisted so also verify that the grip isn't rubbing against the switch housing.



Last edited by Laitch on Mon Nov 07, 2022 11:40 pm; edited 1 time in total (Reason for editing : ambiguity)


__________________________________________________
1995 K75 81,000 miles
My mojo don't go Usa-lo10
    

38Back to top Go down   My mojo don't go Empty Re: My mojo don't go Mon Nov 07, 2022 8:07 pm

duck

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Laitch wrote:Remove the cover of the throttle gear and chain assembly to determine if there isn't dried, caked grease fouling up the movement of the gear in there. The throttle should snap back when it's twisted so also verify that the grip isn't rubbing against the switch gear.

Also make sure that the line on the twist tube gears is aligned with a corresponding mark on the gear that pulls on the chain. And spray that stuff down with aerosol silicone to improve throttle return.

Another thing that can hold the throttle open is the end of the throttle cable not fully seated here:

My mojo don't go 0oTQ9R7


__________________________________________________
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
    

39Back to top Go down   My mojo don't go Empty Re: My mojo don't go Mon Nov 07, 2022 10:28 pm

Point-Seven-five

Point-Seven-five
Life time member
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You might want to slide the right grip a quarter inch further out on the bars so the end of the grip isn't rubbing on the end of the handlebars.  I have also had issues with heated grip wires preventing the throttle from fully closing on my K75.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

40Back to top Go down   My mojo don't go Empty Mojo no go Mon Nov 07, 2022 11:09 pm

daveyson

daveyson
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Has your brick always had this high idle problem? I see yours is an 85 model, like mine. There were a few changes in 85. Unlikely but you might have a cable of the wrong length. Check which month of 85 your brick is to see if you have the right cable. I think an earlier one has an adjustment near the top. 

Check also that the cable is set deep enough into the quadrant at the bottom.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

41Back to top Go down   My mojo don't go Empty my mojo don't go Tue Nov 08, 2022 2:27 pm

Bluebeemer

Bluebeemer
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Tks, guys; will do! According to Vin my bike was built in November of 84. I don't remember a high idle being an issue in the past. I've had the bike for a couple of years and used it only minimally, too busy staying afloat. The high idle became apparent when the bike ran so much better by cleaning out the fuel tank and replacing the fuel filter plus a bunch of lesser details that were fixed, I suspect. I don't think a tight throttle cable is the issue, but a good going over couldn't hurt.

    

42Back to top Go down   My mojo don't go Empty Mojo no go Tue Nov 08, 2022 3:03 pm

daveyson

daveyson
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If this is with the choke on, maybe check how it is with the choke off, or adjusted.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

43Back to top Go down   My mojo don't go Empty Re: My mojo don't go Tue Nov 08, 2022 3:07 pm

duck

duck
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daveyson wrote:If this is with the choke on, maybe check how it is with the choke off, or adjusted.

Just loosen the locknut on the TB end of the "choke" cable and screw it in until you're sure that there's a little slack in the cable.

My mojo don't go K75pa.ab.tb.67.chokecablelocknut


__________________________________________________
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
    

44Back to top Go down   My mojo don't go Empty my mojo don't go Tue Nov 08, 2022 9:21 pm

Bluebeemer

Bluebeemer
active member
active member
Choke cable is slack at the adj point as per pic. It just occurred to me that the Beemer now starts without the choke easily, before cleaning/changing fuel filter etc I had to use the choke all the time from day one of owning it. I plan next to disconnect throttle cable at throttle valve level and start bike to ck idle speed. If still high, it rules out any throttle cable back to hand grip issues as cause of fast idle. I keep thinking it may be an air leak somewhere, but because I can lower the rpm somewhat by pressing down on the idle adjustment screw; that suggests it is not an air leak, yes? The idle goes back up again when I release the pressure. All of this seems to lead to some kind of relatively minor obstruction preventing the valves from closing completely. If the bike were British I would expect these issues to be normal, but it's not British; it's a BMW.  Tomorrow is another day!

    

45Back to top Go down   My mojo don't go Empty Mojo no go Tue Nov 08, 2022 11:57 pm

daveyson

daveyson
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But can you see some free play or movement at the roller between throttle bodies 3 and 4 when engaging the choke? It's just above the blue bit in the photo. It might be stuck in the engaged position, preventing the valves from closing completely.

That might explain why you now have a high idle and no longer need to use the choke. 

My mojo don't go Img_2090


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

46Back to top Go down   My mojo don't go Empty my mojo don't go Thu Nov 10, 2022 7:01 pm

Bluebeemer

Bluebeemer
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Duck, I think you have it right! But, Daveyson started me in that direction re: the choke malfunction possibility. I spent a good hour staring at the throttle linkages trying to figure out exactly how everything worked together. With a very good led light and a mirror I was looking for the throttle cable where it comes thru to the throttle valve cam. Damm if it did not look like the throttle cable sleeve was not pushed all the way thru, only the wire was thru. It was not very easy to see so I still have to verify it some other way. I'm expecting to be able to reach it from the other side once the gas tank is moved out of the way. Wish me luck!

    

47Back to top Go down   My mojo don't go Empty Mojo no go Fri Nov 11, 2022 4:07 am

daveyson

daveyson
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Erm, I suggested other possibilities after you posted that you didn't think a tight throttle cable was the issue.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

48Back to top Go down   My mojo don't go Empty Re: My mojo don't go Fri Nov 11, 2022 11:59 am

Bluebeemer

Bluebeemer
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active member
Daveyson; you really pointed me in the right direction. I did check out your choke malfunction idea in detail, it was working. I also sprayed everything thoroughly with carb cleaner which clarified specific items muchly. I was not expecting to find anything much at all. I actually was obsessing about whether the injection valves were properly synchronized and what it would take to do that. Checking throttle cable looseness was confirmed at the handlebar end, but that did not include tightness over the throttle valve cam. My intention was to disconnect the cable at that end but was not sure how to do that, so it was lower on the to do list. Had I done that I would have figured it out myself. What helped a lot was that I had recently bought a battery powered inspection light that was very bright and yet small enough to get up close to the injection valves. I used it to do the choke inspection and was impressed with how much I could see even using a small mirror which I'm sure you know is no mean feat; being on a roll I kept on going to see how to disconnect the throttle cable at the motor end which I never did get disconnected. I did see what appeared to be that the throttle cable was not fully seated coming thru the bracket going to the valve cam. It's not confirmed yet nor is it fixed.  Duck posted the pic of the throttle cable not seated properly which is why I mentioned his name. I want to say that everyone has been very supportive and encouraging in helping me learn about Beemers. I'm really glad I joined the forum. I did sleuth around a bit before joining but what has impressed me a lot since joining is the international comradship of the group, including even fellow Dutchmen as so am I one too, tho having lived in the States 90 percent of my life. So once again, thanks for all the help and support. Gonthar

I apologize for all the words, what with Covid and being a widower I spend too much time alone these days.

    

49Back to top Go down   My mojo don't go Empty my mojo don't go Fri Nov 11, 2022 12:05 pm

Bluebeemer

Bluebeemer
active member
active member
Daveyson, one more thing, I reviewed all your posts regarding high idle issue and I noticed you did mention throttle cable not seated properly. but I did not understand exactly what you meant so I missed it. So my apology

    

50Back to top Go down   My mojo don't go Empty Mojo no go Fri Nov 11, 2022 5:12 pm

daveyson

daveyson
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Actually I think we were just both on a different wavelength, not the first time I've done that. 

It might be easier to see from behind, it's not too hard to remove the bottom of the airbox.

If you want to remove the cable, you will see a slot in the quadrant to the barrel of the cable. If you line up the cable with the slot, then push the cable through the slot, then keep pushing, and the cable will be free from the quadrant.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

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