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1Back to top Go down   K75RT Wont Run Empty K75RT Wont Run Wed Feb 02, 2011 6:58 pm

hammerboy86

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Hi guys,
My first post, great forum btw.
I have a '91 k75RT which starts (only runs a few secs, then dies), it ran perfect when i first bought it (only rode 30 miles on it so far!), like an idiot i let the battery run flat, so i jump started it and let it tick over to charge the battery.
After about 25mins, i went to check on it to find a plume of steam coming out from under the seat/tank area.
Doesn't run properly now, the scenario goes like:
Starts 1st turn, runs badly for 20 secs, then dies. Re-start, runs for about 5 secs, then dies and wont restart until the next day and does the same!

I dont know the K's very well, but love the bike and dont want to consign it to the scrapheap without a fight.
Does it sound like a head gasket failure or a roasted engine?
Knackered injector?
Fuel pump seems to be pumping ok as i can hear it switching on and can see fuel returning back into tank.
Could it be old contaminated fuel? (Dont know for sure how old the fuel in it is)
Dont want to take it to a bike shop to have them experiment at my cost, when i could experiment just the same!
thanks

    

2Back to top Go down   K75RT Wont Run Empty K75RT no go Wed Feb 02, 2011 8:09 pm

Stout

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Welcome Hammerboy!

It sounds like when you left it idling, your fan did not cut in when it should have and you boiled it. Not good. Latent failures of the cooling fan are not uncommon on these models - I'm still not sure mine works, for example. Since the cooling fan only exists for low speed operation, a latent failure is never likely to be a problem if you can keep moving.

For what it's worth, I will never run a bike (or any other vehicle really) stationary for any extended period. It is far better to get on and ride it. For your specific aim in this case, charging system output is much lower (almost nothing) at idle anyway but there are a multitude of other reasons why it is better to have any vehicle out & moving around. If you can't do this (eg: weather is to crappy) you should consider if you really need to do it right then. The horse has bolted now, but I suggest you buy a battery charger and use it instead in future.

On to your new problem. Since it was running perfectly before, it is quite reasonable to suspect the problem has something to do with the overheating episode. Damage to the head gasket and / or head itself is a real possibility. I recommend you start by checking coolant and oil levels, check for oil in the coolant, coolant in the oil and do a compression test. If you don't own and don't want to buy a compression tester, I suggest taking it to a mechanic.

With the compression test, do one cold, then put the plugs back in, try and start it and once it has done it's thing, pull the plugs and do another compression test. For your own safety, the continued wellness of your compression tester and to avoid unnecessary unburnt fuel contaminating your bores & sump , it is best to pull the fuel pump relay for the compression tests.

Best of luck and let us know how you go.



Last edited by Stout on Wed Feb 02, 2011 8:16 pm; edited 2 times in total (Reason for editing : Safety detail added)

    

3Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Wed Feb 02, 2011 8:28 pm

hammerboy86

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Howdy stout, thanks for the reply.
I think i'll try a compression tester, seen a cheap one in halfords K75RT Wont Run 112350 . Difficult to see oil levels too, as viewing window on sump is scratched, couldn't see any of the oil/water goo when a gasket goes, although the gasket could still be gone. I dont want to start messing around taking the head off unless i have to as i dont know what other engine damage there may be that would need putting right
thanks
hammerboy

    

4Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Wed Feb 02, 2011 8:35 pm

Stout

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@hammerboy86 wrote: I dont want to start messing around taking the head off unless i have to as i dont know what other engine damage there may be that would need putting right

Exactly mate! The results of the two compression tests should tell you if you have a problem that requires removing the head. A clear result won't guarantee everything is perfect in there, but if it isn't significant enough to show up on a compression test, it isn't significant enough to stop the engine from running.

    

5Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Wed Feb 02, 2011 9:41 pm

K-BIKE

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When you do the compression test what do the plugs look like? What compression figures are you getting (don't forget to do it with ignition disconnected so it cannot spark and fuel pump not pumping. and with wide open throttle during compression pump up.
Regards,
K-BIKE

    

6Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Thu Feb 03, 2011 2:22 am

charlie99

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hmm sounds like some sort of a temperature sensor / ignition coil over heat / hall effect to me ..... but im a newby ...would be great to find out what it is ....good luck hammerboy !!!!


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OK75RT Wont Run 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 ..
    

7Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Thu Feb 03, 2011 1:06 pm

hammerboy86

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thanks guys , i'll keep you posted

    

8Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Sun Feb 06, 2011 6:51 am

ReneZ

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You could also have cooked the battery by running it without any charging current (the alternator only really starts charging at 1500-2000 rpm).

If the bike overheats it normally starts boiling over at the radiator cap, dumping the boiling liquid into the header tank until the little connecting hose goes and it then drops it over the bike. Did you see where the steam was coming from?

There are some easy checks in Bert's fault finding info to see if the fan is indeed faulty etc. (look under 'portal' at the top).


__________________________________________________
Greetings from Florida! Having a 'new' K  :cyclops:    Surprised-o: 

Rene


BMW K100 - 1985 (0030029) K75RT Wont Run Rain
BMW K1200GT - 2003 (ZK01223)
    

9Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Sun Feb 06, 2011 7:26 am

charlie99

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? does the spark stop when the stop event happens ...or is it something else ?
i have seen igniter modules die ...giving similar faults ( igniter sits directly above radiator and under the tank )

    

10Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Sun Feb 06, 2011 6:19 pm

hammerboy86

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ReneZ:
I've already put a new battery in, the knackered one was only dated 2009 and was OEM, think the cd player stayed on and flattened it. You're from bridge of weir? only an hour or so from me in dunfermline.

Charlie99:
Dont know if the spark stops when the bike wont start, i'll need to check that next, along with a quick look at if the plugs are wet or not.
thanks

    

11Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Mon Feb 07, 2011 3:02 am

charlie99

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hope it turns out something simple hammer ...but do all the checks i guess .....good luck


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OK75RT Wont Run 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 ..
    

12Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Wed Feb 16, 2011 3:20 pm

hammerboy86

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Have done a compression test on the cold engine, all 3 cylinders were around 130psi, front cylinder was around 2psi more.
Plugs were soaked with fuel, which i could also smell out the exhaust when turning over (but not starting!).
I'm also getting a spark on all 3 plugs.
Any ideas on the next line of enquiry?

    

13Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Wed Feb 16, 2011 6:53 pm

charlie99

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hmmm how is the vacume line to the fuel presure regulator ?.. it hasnt poped off ?

sounds like the next test to me .

while your there check the engine breather to plenum for cracks/ leaks and also the tps (throtle position switch ) rear of the throttle bodies to see if it clicks on opening the throttle.

doh .!!!!! oops scratch that ....you did say that you were sure that the fuel was making it back to the tank....was thinking that it could have been a presure build up , swamping the cylinders ......well it fitted the condition you now have

    

14Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Sat Feb 19, 2011 9:09 pm

K-BIKE

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Spark plugs out spin over the engine with the fuel disconnected by the plug to the tank so the pump doesn't run and reconnect, you can do Bert's trick of the blowtorch in the spark plug hole to get rid of excess fuel then heat up the plugs, pop them back in and try for a start. When the plugs get wet with fuel the K and many another engine is unlikely to start. Fuel, air, compression and spark should result in engine running.
Regards,
K-BIKE



Last edited by K-BIKE on Wed Feb 23, 2011 12:56 am; edited 1 time in total

    

15Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Tue Feb 22, 2011 6:14 am

hammerboy86

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Did what K-BIKE suggested above, bike now runs Very Happy !
Looked like it was burning coal when it first started! Took it out for a little spin, now just have to sort the other stuff.....
thanks for the input guys

    

16Back to top Go down   K75RT Wont Run Empty Re: K75RT Wont Run Tue Feb 22, 2011 7:06 am

charlie99

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wohoo !!! win


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OK75RT Wont Run 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 ..
    

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