BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   Thermostat Question Empty Thermostat Question Mon Apr 11, 2016 10:44 pm

Bikesmith

Bikesmith
Silver member
Silver member
Hi everyone!
    I'm trying to track down an overheating problem... maybe. On the first real ride after I got my 1985 K100rs running, it wouldn't hot start. Someone suggested that the FICU is not letting the bike start because it thinks the bike is too hot. I'm pretty sure my temperature sensor is faulty. I'm replacing it. In the meantime, I'm checking out the whole cooling system just in case.
   I drained the system and pulled the radiator today. It had green coolant, which I've been lead to believe is bad. Not aluminum specific, right? I'll refill with the correct stuff after a flush.
   I also cleaned a ton of bugs and grains of sand out of the radiator and straightened a few bent fins.
   I'm checking the thermostat, and it seems to be opening a little hot. The Clymer book says it should open at 176-185F. It's opening at more like 190-195F. Is that a problem? Should I replace it? If yes, any suggestions for an inexpensive replacement thermostat? I haven't even looked at the BMW price. I'm sure it's ridiculous.
  Thanks guys!
   -Jon


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

2Back to top Go down   Thermostat Question Empty Re: Thermostat Question Mon Apr 11, 2016 11:01 pm

Holister

Holister
Life time member
Life time member
My Haynes manual says it opens at 185oF and should be fully open at 198oF
I think anywhere around there would be ok.

Pretty much all coolants are suitable for alloy engines these days


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Thermostat Question Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

3Back to top Go down   Thermostat Question Empty Re: Thermostat Question Mon Apr 11, 2016 11:19 pm

RicK G

RicK G
admin
admin
It should be marked on the thermostat and probably is 88°C which is 190.4°F. That will be its start to open temp and usually they are fully open at about 5°C or 9°F more.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

4Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 1:23 am

brickrider2

brickrider2
Life time member
Life time member
A search of this forum will disclose some considerable back and forth on the question of thermostats.  What you now have can rather easily be checked with a pot of water and a thermometer.  
I don't think the color of the coolant has anything to do with whether it is compatible with aluminum or not. The coolant I have is definitely green, and it says on the container it is good for aluminum engines.  Now, the BMW dealer may have another story for you, but....

    

5Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 1:54 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Sounds like your thermostat is working properly.  These engines are designed to run around 200F and even higher when you're stuck in traffic.  In the summer you will sometimes think the engine is on fire.  It's perfectly normal, just get out on the highway and open her up. 

If a previous owner cheaped out and used hard tap water like mine did you might have to do a couple of flushes to get all the crap out so it can run cooler.  Always use distilled water.  I get mine from our dehumidifier.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
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
    

6Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 2:19 am

Holister

Holister
Life time member
Life time member
I just use demineralized water from the supermarket. Its used in steam iron and costs $1/litre. I always mix it up about 25% stronger than recommended. That way I can just top it up with some water once in a blue moon when needed. But my old girl doesn't use much coolant. I've probably used about 2 or 300ml over the last 12 months. I'd be surprised if you found some coolant that wasn't alloy compatible.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Thermostat Question Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

7Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 5:02 am

charlie99

charlie99
VIP
VIP
there are a few alternative thermostats that work in varying degrees

recently released is a 86c ...high flow version  suitable for Toyota corolla series ..(and many others )

the standard series thermostats for the same series of vehicles is moderately priced ...the high flow version carries a premium price ...but still is way cheaper than the bmw part ... the range includes the 88c version as well *( I believe this is the stock temp rating for many vehicles including the k  )

the real issue is finding the rubber surround gasket that fits the thermostat and the housing ...I have found one that fits almost perfectly ...although the profile is slightly different ,,, just a slight amount of carefulness is required in the installation ....long term feedback is that I find it to work as it should ...and that seal does the job quite well

we have to recognise that high temps in the k bike are not a unknown thing ,,,I find that with ambient temps of around  28c  quit bearable and all is good ...even better when temps are below this ...and I guess many have this as a standard ...for the folks in hotter areas where the frequency of 25 c and above constantly, the extra heating effect is very noticeable ..burnt inner thighs is a common complaint ...

after a recent head gasket issue in my car ...I think I will defiantly be using demineralized water as the additive to the glycol coolant concentrate , that makes the coolant mix that I like .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OThermostat Question Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

8Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 7:33 am

Gaz

Gaz
Life time member
Life time member
Guys, genuine BMW premixed coolant (use straight out of the bottle) is GREEN and is not that expensive. Comes in 1.5 litre bottles. Puts the mind at ease.


__________________________________________________
Gaz
1990 K75 6427509; 1987 R80G/S PD 6292136; 2010 G650GS ZW13381; 95 K1100LT 0232224
    

9Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 8:57 am

Holister

Holister
Life time member
Life time member

Thermostat Question B000J680AM_230
eeeehhh!!
Coolant Schmoolant!

Its all green to me


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  Thermostat Question Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

10Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 9:11 am

92KK 84WW Olaf

avatar
Life time member
Life time member
Ribbid!


__________________________________________________
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 37,190 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
    

11Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 10:54 am

Bikesmith

Bikesmith
Silver member
Silver member
Okay, it seems that A) My thermostat is fine. It's starting to open at the rated temp and fully open 5-10 degrees higher. From the Clymer manual I got the impression that it should start to open 10 degrees below the rated temp and be fully open by the rated temp.
  And B) I guess I was wrong about the coolant. In one of the Chris Harris videos he got all hot and bothered because he found green coolant in a bike he was working on. He said coolants are color-coded by their use and that green means it's for an iron block. I should have checked on that before taking it as confirmed.

   Thanks as always for your help!


__________________________________________________
Jon
Mechanically competent, electrically idiotic
------------------------------------
1985 BMW K100rs
1940 Royal Enfield WD/CO
1968 Honda CL125
    

12Back to top Go down   Thermostat Question Empty Re: Thermostat Question Tue Apr 12, 2016 11:16 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Yeah, green coolant isn't such a big deal anymore.  Back when these bikes were new the green stuff frequently had the wrong additive mix and could cause problems.  There were a lot of warnings about using it.  Now, it's almost impossible to find an iron block and even the green stuff is compatible with aluminum now.

But old ideas die hard...


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
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
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum