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1Back to top Go down   K100 won't start after winter sleep Empty K100 won't start after winter sleep Thu Mar 25, 2021 6:34 pm

Tarlin

Tarlin
active member
active member
Hi,

after the bike spent the winter hibernation in the garage, it won't start. The problem started last year, same, after winter, but eventually as the weather warmed up it fired up, and ran without any issues for the whole season.

This year it is happening again. About a month ago, I was able to start the bike, connected to the car battery, but only after prolonged starting.

-The bike now has a new battery with a 400A start current, so the battery is definitely not the issue here, the starter motor also turns the engine without any hesitation.

-I put in a set of new spark plugs, just in case. Even tried the Criss Harris youtube procedure with adding 10ml of oil in each cylinder to improve compression, but to no avail.

-all 4 spark plugs tested for spark, looks ok. Spark plugs look moist with gasoline, smell of gasoline, so I guess the injectors are ok? Also the fuel pump seems ok, you can hear it.

-when I try to start the bike with the choke on, it just cranks, but shows no lust for life:)

-when I try to start the bike without choke, after a few seconds it kind of wants to power on, but doesn't. Last time (one month ago) I started it, it also started without choke, run very erratic, until I put the choke on, then it idled beautifully, and ran very nice afterwards.

Any ideas or suggestions would be appreciated!


__________________________________________________
1987 BMW K100, VIN:0093523
    

92KK 84WW Olaf

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Life time member
Life time member
Use the choke to start it!


__________________________________________________
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 51,800 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
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Check the crankcase breather hose and the throttle body air caps for cracks. Air leaks can make the starting air mixture too lean to ignite.


__________________________________________________
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
    

gorio

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Silver member
Silver member
Remove then old fuel from the tank and add new. If that is not possible at least add a little menthol alcohol to the mix.

Pull the fuse for the fuel pump and pull the spark plugs. Crank the engine over for several short bursts. This should help remove oil and fuel from the cylinders.

Dry the spark plugs before re-installing. heating them with a lighter works. Just remember the fuel on them may light up.

Put everything back together maybe checking again for spark before re-installing the fuse for the fuel pump.

Pull choke to the second notch and crank, again in short bursts.

Does it fire at all or just crank?

If it is still cool in your part of the world the oil and gas that has made its way into the cylinders will take a very long time to evaporate on their own. The above should help.

This may not be the cure but it would be a good start.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

Laitch

Laitch
Life time member
Life time member
gorio wrote:Remove then old fuel from the tank and add new. If that is not possible at least add a little menthol alcohol to the mix.
The advantage of using menthol alcohol is that it sweetens your breath.  Smile

Some garage environments promote condensation in the fuel tank which will degrade the fuel. Like gorio indicates, suck that old fuel from the tank, add fresh fuel, charge up the battery then start your moto. Next year when you put it up for winter, fill the tank with fresh fuel and add fuel stabilizer like STA-BIL. When spring comes, your moto will probably start.


__________________________________________________
1995 K75 90,000 miles
    

gorio

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Silver member
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Laitch wrote:
gorio wrote:Remove then old fuel from the tank and add new. If that is not possible at least add a little menthol alcohol to the mix.
The advantage of using menthol alcohol is that it sweetens your breath.  Smile
>Mi spelin not alwies so good


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

Tarlin

Tarlin
active member
active member
Thanks for the advice, will try those things and report back!


__________________________________________________
1987 BMW K100, VIN:0093523
    

Tarlin

Tarlin
active member
active member
Point-Seven-five wrote:Check the crankcase breather hose and the throttle body air caps for cracks.  Air leaks can make the starting air mixture too lean to ignite.
Do you maybe have a picture where the crankcase breather hose is located?


__________________________________________________
1987 BMW K100, VIN:0093523
    

Laitch

Laitch
Life time member
Life time member
This is a photo from a K75. The green arrow points to the coil cover at the rear left-side of the engine. Yours will look slightly different. The orange arrow points to the throttle switch. The hose is circled.
K100 won't start after winter sleep K75-le10


__________________________________________________
1995 K75 90,000 miles
    

10Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Fri Mar 26, 2021 10:53 am

92KK 84WW Olaf

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The circled hose is commonly referred to a the 'Z pipe'. They fail in time and cause very bad running. It can be replaced through that gap, have done 2 of them.


__________________________________________________
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 51,800 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
    

11Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Fri Mar 26, 2021 11:00 am

Point-Seven-five

Point-Seven-five
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The Z-pipe is one of the first things I check when I bring a new brick into the fold. So far, I've replaced it on all but one of my bikes. The bends in that tube along with the hose clamps are tough on it.

One caution, you don't have to go nuts tightening the clamps on it. Just snug will get the job done, and doesn't damage the rubber.


__________________________________________________
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
    

12Back to top Go down   K100 won't start after winter sleep Empty Update - it's alive Fri Mar 26, 2021 5:14 pm

Tarlin

Tarlin
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active member
Thanks for all the tips, I will definitely check and replace the Z hose, I just need to find a new one. Even if it is not the cause (yet), is is 30+ years old so replacing it would not hurt the bike:)

So, status update: before doing anything (except buying a fresh can of 100 octane gas, which will be need anyways), I decided to try one more thing, just like last year: I put the bike out of the garage, on the sun. Let it sit in the sun for about an hour, and then it started, without any drama.Did about 30km then, runs perfect. What puzzles me is the reason, why won't it start in the cold garage (still about 5-10 degrees Celsius inside, not ,minus, far from it)
I was trying to start it for 5 days, drove me mad. As soon as I let it warm up in the sun for about an hour, it started like it should. So I guess it is like it's owner, functions best in sunny weather:)))
It does bother me though, as I can't find the reason for that...


__________________________________________________
1987 BMW K100, VIN:0093523
    

Tarlin

Tarlin
active member
active member
One more thing: It started on "old" gas that I put in the tank end of November, before putting it to hibernation. Old gas was one of the first things suspected last spring, so I drained the tank, and put fresh fuel in it. Did nothing:) Started only after beeing left in the sun to warm up:)
What is funny is that in the autumn, on last rides, started without problems, even in lower temps. The problem just happens in spring after hibernation....


__________________________________________________
1987 BMW K100, VIN:0093523
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Condensation.

Sitting in the garage on a warm day in the early spring, water condenses and gets into everything. Putting the bike out in the sun for a couple hours dries everything out.

Usually it's the plug wires and the coils that suffer the worst. The water bleeds off the spark.


__________________________________________________
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
    

15Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Sat Mar 27, 2021 12:10 am

gorio

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Silver member
Silver member
Just curious as to how it runs in the rain?

I would try draining the bike or using fuel stabilizer next fall  and see how it goes next year.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

Tarlin

Tarlin
active member
active member
Point-Seven-five wrote:Condensation.

Sitting in the garage on a warm day in the early spring, water condenses and gets into everything.  Putting the bike out in the sun for a couple hours dries everything out.  

Usually it's the plug wires and the coils that suffer the worst.  The water bleeds off the spark.  
This sounds about right...what puzzles me is the fact that I have changed the sparkplugs, sprayed some contact cleaner in the ignition caps, but nothing. Only after being in the sun it started. Could be that the main source of the problem has been the igniton coil, as I have not touched that.


__________________________________________________
1987 BMW K100, VIN:0093523
    

Tarlin

Tarlin
active member
active member
gorio wrote:Just curious as to how it runs in the rain?

I would try draining the bike or using fuel stabilizer next fall  and see how it goes next year.
I try to avoid riding in rain as much as possible:))) But I did go trough some heavy storms last year on roadtrips, and it worked without a hitch. I'm not sure we even have fuel stabilizers in EU, at least I never saw one:))) I put the 100 octane fule in the tank in Nov, and after it started again, used the tank without any issues, so that leads me to believe it was not the fuel.


__________________________________________________
1987 BMW K100, VIN:0093523
    

gorio

avatar
Silver member
Silver member
I put the 100 octane fule in the tank in Nov, and after it started again, used the tank without any issues, so that leads me to believe it was not the fuel.
I wonder what the attraction to 100 octane is? Did you know it is much harder to light then a lower octane regular fuel? It also actually contains less energy then regular fuel.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
There are a lot of components and connections involved in making the spark on the K bike. Condensation can get into places you have a hard time even finding. A couple hours in the sun gets to those places.

Some of those places are the Hall sensors and their connector, the ignition control module under the tank and it's connector, the Jetronic and it's connector, and the connections and insulation around the coils.

Some of these parts are protected pretty well from rain and splashing water, but not water vapor in the air that can get into every nook and cranny. Capillary action also helps get the moisture into hidden places as well.


__________________________________________________
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
    

Tarlin

Tarlin
active member
active member
Point-Seven-five wrote:There are a lot of components and connections involved in making the spark on the K bike.  Condensation can get into places you have a hard time even finding.  A couple hours in the sun gets to those places.  

Some of those places are the Hall sensors and their connector, the ignition control module under the tank and it's connector, the Jetronic and it's connector, and the connections and insulation around the coils.  

Some of these parts are protected pretty well from rain and splashing water, but not water vapor in the air that can get into every nook and cranny.  Capillary action also helps get the moisture into hidden places as well.  
Thanks .75, this seems the most probable explanation! 

The bike is like it's owner, works best when exposed to sunny weather. 

In all seriousness, I really do think that condensation is the issue here, as I can't find any other logical explanation. The solution for two years in the row has been a few hours worth of drying out in the sun.

Change of spark plugs, battery, and fresh fuel brought no results, the Z pipe also seems ok, the only thing that helped was to let it sit in the sun and fresh breeze, and then it started like a champ, and has had no problems starting since then. Also tried it starting on a fresh morning since then (sub zero temp) and it exploded into life with ease.

So, my plan is to add fuel stabilizer(thanks @Gorio) next autumn (found it online), and see if that changes anything, and if not, just aim the low temp/high flow hot air heater onto the bike for a while, and then start it.

Thanks everyone for the tips and suggestions, sincerely appreciated.


__________________________________________________
1987 BMW K100, VIN:0093523
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
How tight is your garage where the bike is stored? Some ventilation is important to reduce the amount of condensation that forms over the winter and especially in the Spring.

I try to run the engines in my bikes a couple times a month during the winter specifically to keep the battery charged and to warm things up enough to dry out any condensation that might form. I let them idle until the fan has had the opportunity to cycle 2-3 times. After they cool off for a couple hours I put their covers back on them.

One other concern with condensation is the corrosion it causes on unprotected parts of the bike. It can be especially bad if the bike is stored in a garage with a car that is used on roads that are treated with salt. As a prevention, I give my bikes a good wash before the winter to remove any dirt that will hold moisture and then give them a spray with a corrosion protectant. S100 makes a good one. I spray everything on the lower half of the bike avoiding getting any on the brake rotors. A bonus is that opening the garage to remove the exhaust also helps to ventilate it as well.


__________________________________________________
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
    

Tarlin

Tarlin
active member
active member
Actually the garage is a shed:) So there is plenty of room (could store 2 cars, only has the K100, a couple of bikes, lawn mover, and some garden tools), and no other motor vehicle inside. The bike is connected to the battery charger all the time during storage, and I did try to start is a few times in winter, but with no success (After storage it sat initially for one month as I was away for work).
The shed itself is insulated, but not heated.


__________________________________________________
1987 BMW K100, VIN:0093523
    

Holister

Holister
Life time member
Life time member
Could be either condensation as Point-Seven-Five suggests or maybe a temperature sensor issue.
I would start with making sure all your ground points are clean and bright. Ensure that the plug for your ignition control module at the headstock is clean and firmly in place with the rubber boot, and same for the ECU.
Check your temp sensor is in spec with a DMM. Instructions are in the Trouble Shooting page.
You say that the Z-pipe "seems ok".... well, mine looked ok first time I worked out what it was, but it was a different story when I took it off.
One place that tends to get corrosion badly is inside the coil towers.
When you're replacing the fuel in the tank, don't forget to flush the new fuel thru the fuel rail also.
It's seems a little weird. Hope you find out what's happening.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
 K100 won't start after winter sleep Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

24Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Sun Apr 11, 2021 10:32 am

Laitch

Laitch
Life time member
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Tarlin wrote:I'm not sure we even have fuel stabilizers in EU, at least I never saw one:
You have them for sure and this is not the only one on offer. Whether you use it depends upon how long your moto remains idle at a stretch and whether you use petrol with ethanol in it.


__________________________________________________
1995 K75 90,000 miles
    

25Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Sun Apr 11, 2021 10:37 am

Tarlin

Tarlin
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Thanks @Laitch, I actually found this site trough another thread, and man...they have a lot of stuff for our old mules cheers. Might actually try the LiquiMolly stuff from the same site. A bit cheaper, and made by "ze Germans", so there should be no efficiency "lost in translation" Very Happy


__________________________________________________
1987 BMW K100, VIN:0093523
    

26Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Sun Apr 11, 2021 11:52 pm

Matthew-Brisbane

Matthew-Brisbane
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Qustion 
What's a winter sleep  ? 

That the best time to ride  out here, clear blue skies, internal heat from the engine


__________________________________________________
1986 K100 RS Motorsport
1988 K100 RS SE
1990 K1 known as Barn Find 
2004 F650 GS known as DACK-DACK
 
#### K100 RS Project 
2011 R1200 GS known as Big Blue 
    

27Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Mon Apr 12, 2021 12:00 am

Laitch

Laitch
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Matthew-Brisbane wrote:What's a winter sleep  ? 
K100 won't start after winter sleep Winter10


__________________________________________________
1995 K75 90,000 miles
    

28Back to top Go down   K100 won't start after winter sleep Empty Re: K100 won't start after winter sleep Mon Apr 12, 2021 11:17 am

Point-Seven-five

Point-Seven-five
Life time member
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lol!


__________________________________________________
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
    

barney t weasel

barney t weasel
active member
active member
Try "Start Ya Bastard" a great product we have here in Australia. Mostly ether...it works.

    

jnclem

jnclem
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So, just a thought, have you visually checked to see that the "choke" cable/high idle cable, is actually doing something? If it isn't, you could just use the throttle of course, but it really does help in cold weather. I know when I try to start mine below 40 degrees, it really like some extra.

    

Tarlin

Tarlin
active member
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Yes, thanks for the idea, but the choke works perfectly!


__________________________________________________
1987 BMW K100, VIN:0093523
    

Tarlin

Tarlin
active member
active member
Holister wrote:Could be either condensation as Point-Seven-Five suggests or maybe a temperature sensor issue.
I would start with making sure all your ground points are clean and bright. Ensure that the plug for your ignition control module at the headstock is clean and firmly in place with the rubber boot, and same for the ECU.
Check your temp sensor is in spec with a DMM. Instructions are in the Trouble Shooting page.
You say that the Z-pipe "seems ok".... well, mine looked ok first time I worked out what it was, but it was a different story when I took it off.
One place that tends to get corrosion badly is inside the coil towers.
When you're replacing the fuel in the tank, don't forget to flush the new fuel thru the fuel rail also.
It's seems a little weird. Hope you find out what's happening.
I will have to check the temp sensor, but I can't find the info on how to test it. Me and internet:))) If somebody has a link, would be great.
Now regarding the temp sensors. I am looking at tills.de, and they have 2. Normally I would buy the original Bosch one,as it is 35 EUR, but it is not on stock. They do offer an alternative (read:chinese crap probably) that is only 15 EUR, but I am hesitant to buy it, as it takes some labor to replace. Anybody has an experience with this sensor?:

https://www.tills.de/temperature-sensor-k75-k100-bosch-bmw-61311459197-325.html


__________________________________________________
1987 BMW K100, VIN:0093523
    

mike d

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Go to the portal page (kforum-tech.com) Then in the electrical section look for the 'Troublehooting the EFI (English)' In there you will find full instructions on where to measure the water temperature sensor (plus much more).

Mike

    

Tarlin

Tarlin
active member
active member
Thanks mike d!!!!


__________________________________________________
1987 BMW K100, VIN:0093523
    

35Back to top Go down   K100 won't start after winter sleep Empty Update Mon Jul 10, 2023 5:42 pm

Tarlin

Tarlin
active member
active member
It's been a while, so I just wanted to update the current status: After changing the Z pipe, checking for corroded grounds, changing the temperature sensor, spark-plugs, fuel....the situation repeated itself this winter:) So i brought it to a specialist, and he started checking components (ECU, Injectors, etc). He changed the ECU just to test and make sure it is not the ECU. To make a long story short, he could find no real issue, he did mention he adjusted a few minor things (forgot what exactly, something with throttle), but nothing worth mentioning. After he resembled everything, the bike started and has been running since.... Which is great, but what bothers me is that I do not know what the cause was.... Lets see what winter brings Very Happy


__________________________________________________
1987 BMW K100, VIN:0093523
    

MartinW

MartinW
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It could have been a bad connection that cleared up on reassembly. Bricks especially in wet climates and if stored outside  can have problems with electrical connections. Deoxit and dielectric grease will help in keeping electrical Gremlins at bay.
Regards Martin.


__________________________________________________
1992 K75s
    

37Back to top Go down   K100 won't start after winter sleep Empty another day another issue Mon Jul 10, 2023 6:41 pm

Tarlin

Tarlin
active member
active member
Yes. could be a bad connection, who knows. But it is not in wet climate and it is stored indoors.  

Today another issue popped up...while riding in quite warm weather (30+ degrees Celsius) over a mountain pass, behind busses (1-2 gear mostly), the bike just started behaving like it has no fuel. 
Engine cut out, I suspected something heat related (the water temp was ok), let it cool off, and it restarted. 
This happened a second time, had to wait 30 min, then it cooled down enough to get me to the top of the mountain pass. 
There I switched it off, put it in neutral and rode it to the valley, giving it time to cool off, restarted it and rode it back home  (on the descent the back brake went completely soft 2 times, I guess the brake fluid boiled?).

I messed up as I did not try to restart immediately after dying, to see if the fuel pump works or not when it is hot. So now I have to diagnose it again:) Ride the same mountain pass, have some water with me to cool off the Hall sensor housing, and listen for the fuel pump....

Hondas look more and more appealing Evil or Very Mad


__________________________________________________
1987 BMW K100, VIN:0093523
    

MartinW

MartinW
Life time member
Life time member
Over heating of the fuel leading to vaporization is a known problem in hotter climes. Insulating both fuel lines under the tank the FPR and the bottom of the tank can stop the problem. My 75s had problems with vaporization in the fuel rail when in stop go traffic in 30+ heat. Some owners have also relocated the FPR to a cooler position  or fitted fuel coolers.
Regards Martin.
K100 won't start after winter sleep Hose_i13
K100 won't start after winter sleep Fuel_t14


__________________________________________________
1992 K75s
    

Tarlin

Tarlin
active member
active member
MartinW wrote:Over heating of the fuel leading to vaporization is a known problem in hotter climes. Insulating both fuel lines under the tank the FPR and the bottom of the tank can stop the problem. My 75s had problems with vaporization in the fuel rail when in stop go traffic in 30+ heat. Some owners have also relocated the FPR to a cooler position  or fitted fuel coolers.
Regards Martin.
K100 won't start after winter sleep Hose_i13
K100 won't start after winter sleep Fuel_t14
 Thanks Martin! What is a FPR (non native speaker, sorry)? And the part about redesigning the fairing looks on point also. My legs get terribly hot, I thought a Yamaha MT01 which I used to own was hot, but the K is in another league:)))


__________________________________________________
1987 BMW K100, VIN:0093523
    

MartinW

MartinW
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Life time member
FPR stands for Fuel Pump Regulator it resides in the back of the air filter/ air flow meter housing which has to be removed to access it. I didn't relocate mine but I wrapped it in self adhesive reflective tape. Due to living in a hot climate my Brick has quite a few heat related modifications, insulated lines and FPR the underside of the tank has been covered in double sided reflective foam insulation. Even with those modifications I could still have vaporization in the fuel rail, on hot 30+ days in heavy traffic. I did try a home made fuel cooler which only worked at speed. After tossing around a few ideas with a mate who was a ships engineer/heat engineer I came up with a fuel rail heat shield which dropped the rail temperature an solved the problem. The heat shield has the double sided reflective foam on the back. Unfortunately it only works with Bricks with an exposed fuel rail.
Regards Martin.
.K100 won't start after winter sleep Fuelpr12
K100 won't start after winter sleep Fuel_c11
K100 won't start after winter sleep Heat_s11
K100 won't start after winter sleep Heat_s16


__________________________________________________
1992 K75s
    

92KK 84WW Olaf

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Life time member
Life time member
I suspect you have a condensation issue due to the shed storage. So when you take the bike out after winter, park it for a good polish and check over, tyre check and fluid levels check and lube clutch lever etc etc. Its like any electrical item taken from cold to warm, let it warm up and evaporate off the condensation and they usually have a warning about this.

On the rear brake I have the same issue on my RS. I have a few Ks but the Rs is the only one that boils the fluid and loses pressure. Everything in it is new, disc, pads, master cylinder, caliper seals, fluid, brake lines and nothing stops it if I am enjoying a spirited ride on it. Admittedly I might ride it more like its intended rather than I would on the other others.


__________________________________________________
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 51,800 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
    

Tarlin

Tarlin
active member
active member
Thanks @MartinW, I will try and insulate the bottom of the tank a bit more, it can't hurt. The fuel rail is in my case enclosed (RT), so that is just a design flaw with those early fairing, they are a proper heat accumulator:)

@Olaf, thanks for your contribution, as I have said, now it works, also in the winter after being serviced it worked, but we can't figure out what was the issue and that bothers me. But I am very confident it is not condensation, as I have tried drying the bike with compressed air (de-humidified), used a heat gun and an electric air heater, to no avail.

By the way: does anybody know if the plastic hinges for the side panniers can be obtained anywhere? (FOUND THEM AT MOTORWORKS)The one on the left side, (above the exhaust) broke, so now I use bungee cord to keep the pannier together:)


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1987 BMW K100, VIN:0093523
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Hinges are still available from BMW, which is where I get mine.  There are many models over a long period that used those hinges so I am sure they will be around for a long time.

They are very reasonably priced considering they are OEM BMW parts!

P/N 46 54 2 300 039 Hinge


__________________________________________________
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
    

Tarlin

Tarlin
active member
active member
Point-Seven-five wrote:Hinges are still available from BMW, which is where I get mine.  There are many models over a long period that used those hinges so I am sure they will be around for a long time.

They are very reasonably priced considering they are OEM BMW parts!

P/N 46 54 2 300 039 Hinge
Thanks .75, I just send the inquiry to BMW importer in Slovenia.


__________________________________________________
1987 BMW K100, VIN:0093523
    

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