Morning afternoon all;
Have a puzzle for you which may be an easy fix or impossible to find and I will have to consign the "K" to the deep.

As all good stories go I will start at the beginning.

Some years ago I bought a 84K100RS which the previous owner hardly rode and had serviced at a dealer only.
The bike looked and went well was a good price so I rode her home.

Some months later whilst riding along all electrics shut down for a moment and then back on again, as I had a kawasaki once that had an errant sidestand micro I looked there...mmm nothing ok then take a side cover off and generally joggle all the leads etc...anyhow it came good.

Fast forward 2 years to Coffs Harbour 2 weeks ago when the following happened we stopped to see the sights and the bike would not fire up...plenty!!!!!! of fuel but no go...jiggled the fuses and she started.

Got all the way home to Sydney 1500 odd KMs no problems and then this week if it does not start first kick of the electric leg it will not start at all but just flood....and if it does start it will stall or falter with 10 metres and then restart with starter.

• I have heaps of fuel ( its running out the exhaust joints )
  
• I have spark at plugs
  
• I have good battery
  
• starter works very well
  
• hot weather does not affect this
  

I have cleaned earth points, fuses, battery lead connections, Fuel computer connections, checked that HT leads from coild spark to plugs.

I suspect she is getting way too much fuel but I have a gauge on the fuel line that reads 35PSI.

What does it run like when going?...when it does not hiccup it goes fine.

Was just about to take off to Melbourne some 840KMs away but now I can see me not being able to get started again at the first fuel stop.

suggestions??

Remove the vacuum line from the #4 TB and cap it, see if its any better. I am thinking the FPR is leaking to the vac side and causing the flooding.
Is the fuel consumption any worse than it was?

klompy

is there a lack of spark ?

that is what seamed apparent to me ...I saw that fuel was being fed quite well ...not sure if this was over fuelling ...but certainly was being delivered at a furious rate

but rick might have the solution ...
I seem to recall that those fuel pressure regulator things can become quite unpredictable.... from quite a few posts in here .

perhaps it has something to do with the piston and seat , diaphragm ...whatever is best described as !!!

and all a sealed unit ...bugga

can you borrow a regulator from a friend ?

Aaah yes i thought this possible also but I had placed an inline fuel pressure gauge into the fuel supply line and it holds 35PSI for hours showing that the injectors are not bleeding down quickly and also that it is being regulated to the right pressure. And the fuel usage at the moment is horrible...
What is annoying is that to show this pic I started her up easy as pie...one touch vrooom.
This bike may become what I used to own years ago a SR500...start it right first time or give up.

that being the case
perhaps a good look at the hall effect sensors and cabling might be worth while .
also the earth to the ecu under tank ....

there is a test setup in the "ecu trouble shooting flowchart"-tips post by cf

I guess you have checked the cabling to and from the coils ?
 
the fi relay ...does it have 2 feeds from it ? one to the ignition electrics  and the other to the fi electrics ?

how is the "main earth" connection to the battery and chassis ?

just thinking aloud mate

your beauty deserves better than this erratic behaviour

charlie99 wrote:that being the case
perhaps a good look at the hall effect sensors and cabling might be worth while .
also the earth to the ecu under tank ....

there is a test setup in the "ecu trouble shooting flowchart"-tips post by cf

I guess you have checked the cabling to and from the coils ?
 
the fi relay ...does it have 2 feeds from it ? one to the ignition electrics  and the other to the fi electrics ?

how is the "main earth" connection to the battery and chassis ?

just thinking aloud mate

your beauty deserves better than this erratic behaviour

cables to and from coils...check
main earth as supplied by Alby at Bingara checked and WD40ed
will consult ECU flowchart....take tank off and check all thats underneath....and WD that too....thanks Charlie I am sure its just a small gremlin....although I do have spare CDI/fuel computers....should it be necessary........so i have too much fuel not enough spark....i saw the spark and it was not very frightening at all...

stab in the dark here...dirty contacts in the ignition switch.

or maybe the bloody starter brushes  blakey ,,,its is a weird thing
wish I had a "propper" meter with me the day of the ride meet at coffs   and more importantly a little time to explore

blaKey wrote:stab in the dark here...dirty contacts in the ignition switch.

soaked the ignition in penetrene....probably do to open it up and clean properly...bugger...and I happen to have a spare starter and new brushes ....so that sounds like fun.

charlie99 wrote:or maybe the bloody starter brushes  blakey ,,,its is a weird thing
wish I had a "propper" meter with me the day of the ride meet at coffs   and more importantly a little time to explore

you did display magic....twiddled a fuse and off I went for another 1000KM's.....not working anymore now though...or is it.

"...twiddled a fuse..."

Do you remember which one?

all of them.....its the way I roll...

You said fuel usage at the moment is horrible, and you have a Fuel Pressure gauge that shows 35 PSI - normal.

To me this would indicate that you have one or more injectors sticking open.

Just a thought...

Ignition switch is my guess. Good luck Klompy.

I've got spare injectors if you wanted to swap any over??

Hi Klompy - I had a similar situation on my old K75RT a few years ago where like you say, plenty fuel plenty spark, but no start. Recovery Man said this was commom on the early Golf (same system) and he disconnected the water sensor at the top of the engine block - clicked in another sensor to the wire (Landrover Disco! ) and after cleaning the plugs, turn engine to remove fuel in the cylinders, replace plugs, it fired up first kick.  
On return home, it got the Deoxit treatment and was ok thereafter.
Apparently this sensor, if there is no proper contact, thinks the engine is overheating and tells the ECU to shut down and it will not start until this is fixed.

Hope this helps.

thanks guys preparing to "pull plastic" as they say to gain access ....but just to see what would happen I tried to start with no choke and it almost started but after that no start at all...previous to this it would always start on choke first time.....it really appears that there is far too much fuel but as i said there is 35 PSI being held at the injectors so reg is good, injectors are good....my first will be to disconnect the temp sensor...although yet again the fan came on yesterday which is run by this sensor too????

Rick it says in post 18 bear in mind its normal unless it gets a hiccup, the o/c may be intermittant h/r and cause issues that way so its a simple plug and play for klompy from his other bikes, he does have the tank off and its easier to swap and see rather then dig into the maf although once he's gone in there he can replace it same as ignition or r/h switch block, but he said hiccup so i was thinking el

If the MAF sensor sticks open after take off then it stalls and wont restart.
An ignition switch that is not working can't make it flood and if you think it can then please explain

RicK G wrote:How does an O/C ignition switch cause flooding?

Beats the hell out of me but here's why I'd suspect the ignition switch:

A couple of years ago there was a local guy with a K75 that kept quitting on him and eventually wouldn't start at all.  He took it to a local BMW dealer and spent almost $500 on them to perform various diagnostics like fuel pressure, injectors, hall sensor & ICU swaps.....

Guy called me and asked me to take a look at it.  I told him I was not a mechanic and that I don't work on other people's bikes.  However, I succumbed and, without any promise of results I did take a look at it.  The first thing I did, because it was easy to do and to eliminate it as a possible cause, was swap in another ignition switch.

Bike fired right up.  Guy sent me an email six months later thanking me and telling me that it had run like a top ever since.

I can't say I know exactly what was going on but my GUESS would be that the switch was letting through enough power/volts to run the fuel pump but not enough for the coils.

Not sure if I have a spare ignition switch but I do have spare MAF, temp sensor, ignition computer and FI computer...if it were not such a fantastic day for a ride I would be enjoying the puzzle......oh the coils get power fine from the ignition there is spark at all plugs....it just has trouble igniting the rich mix.
perhaps there are 2 faults one where there is too much fuel for the situation and a cut in electrics intermittently.

To rule out the ignition switch....disconnect it, and bridge the green and the red wire with some crimp
terminals adjusted to the correct diameter and a short length of wire.
Add tape as needed............

John , Keith and I sorted out my light issue , harness connection  of all things , have you tried here, I also encounter issues with the contacts in the switch after prolonged rain ( need some de sprayed in there) , indicators refuse to turn off. let us know if you need assistance with a switch.

It appears I have all I need to have a fun filled Sunday morning....

I hope you get it sorted, very frustrating these electrical bugs.

Are they a pair of old Firey top boots on the desk right of bike in photo?

Regards Bushy

and so begins the fun , good luck mate.

duck wrote:

RicK G wrote:How does an O/C ignition switch cause flooding?

Beats the hell out of me but here's why I'd suspect the ignition switch:

A couple of years ago there was a local guy with a K75 that kept quitting on him and eventually wouldn't start at all.  He took it to a local BMW dealer and spent almost $500 on them to perform various diagnostics like fuel pressure, injectors, hall sensor & ICU swaps.....

Guy called me and asked me to take a look at it.  I told him I was not a mechanic and that I don't work on other people's bikes.  However, I succumbed and, without any promise of results I did take a look at it.  The first thing I did, because it was easy to do and to eliminate it as a possible cause, was swap in another ignition switch.

Bike fired right up.  Guy sent me an email six months later thanking me and telling me that it had run like a top ever since.

I can't say I know exactly what was going on but my GUESS would be that the switch was letting through enough power/volts to run the fuel pump but not enough for the coils.

The last place I would take a K bike is to a dealer, all they know how to do is throw new parts at it till it goes and if that doesnt work they give you the bill for the parts and say tough shit it still dont go.

I am not saying that the ignition switch isnt faulty but it IS highly unlikely and always attack the likely faults first, if it is done from the other direction there lies madness.

If the ignition is absolutely O/C then the fuel injectors cant inject any fuel because there is no power if a High resistance the ECU wont function under 9volts so once again either it works correctly or not at all it is designed to be like that and also is the ICU.
If the barn door is sticky the computer just supplies the fuel it is being told to deliver and a L Jet system hasnt got the sense to know that is rediculous whereas the Motronic has.

It is just as unlikely it is hall sensors as the pump shuts down when there is no signal from the sensors so again no flooding. It is also unlikely to be the temp sensor because the temp sensor can only let the ECU enrich enough for cold starting which isnt enough to cause flooding as John has described because the cold rich only gets down to 4 to 1 mix which will burn with black smoke but very rarely will you get wet plugs.  If a barn door sticks wide openor even half way it will cause a delivery of anything up to 30 times the fuel needed.
Also if the door does stick it is likely that overnight it returns to park and all starts ok but the door jams as soon as revs come up and air flows but when the throttle is turned off it remains open and hiccup then stops and floods as soon as starting proceedure is recommenced, but if it starts immediately all is ok but the slightesy delay while cranking and it floods.

My thinking with fault finding is to eliminate the logical before the illogical scenearios are even given thought.

Though not common per se, ignition switch failures aren't all that uncommon either. Either dirt or wear in the switch workings or the connections on the soldered terminals are aging and becoming dodgy.  Besides if you've got a good one on hand then it's very easy to test to see if that's the problem.

Agreed on not taking a bike to a dealer but many people don't know any better or know of other resources. However, you can't really blame the dealers.  Given the economics of owning an old K bike, the only way to make it affordable is to do most, if not all, of the wrenching yourself or use a good indie shop that has lots of hands on experience with them.  Due to this, many of the dealer wrenches these days have little or no hands on with the old Ks so can only be "manual readers" and run the diagnostics their manuals cover.  Not to mention that they go through training on newer bikes, not our old Ks.

Some time I think that the dealers have all this fancy diagnostic equipment which is necessary to have but they feel obliged to hook it up when a simple bit of thinking will do the job and instead of interogating the system they should ask some pertinent questions of the owner and often one can deduce where the problem is from that or where to start looking at least.
makes me think of an occasion where my nephew had a small hand held game pad and his mother (a blond) was trying to make it work and he was trying to get it from her. She was trying to turn it on and wasnt having any luck, he eventually got the thing and said in a tone only a child can do "first you have to put the batteries in DOH".

An ignition switch isnt one of the complicated things to diagnose but the dealers need a machine to do it. Sometimes I think they couldn't function without their little machine.

Mind the cars nowdays do get complicated. I have a 320i BMW car and the wiring harness in the drivers door is almost as big as the whole of the one on the bike.

update;
yep firey boots on the wall still drying from the last outing.. 

tested AFM by removing from bike...what a shit job...barn door moves easily does not bind..whilst plugged in tested resistance across pins ( @25 degrees ) all within specs given as example.
water sensor tested and spare also tested as comparison both gave correct figure at this temp.
every connection and earth I could find lubed up.....both the FI and the ignition computer tested but changed out as i had spares with all connections cleaned and lubed.....

the only thing I did not change was the ignition switch as it was very easy to access to test after all back together....and the injectors as I take the point that even on full choke the engine still ran fine...

so anyhow I was feeling sort of confident and pressed the starter...and it burst into life....I let her run for a few minutes shut her down and pressed the starter again......vvvrrrroooommmmm.....threw my helmet gloves and jacket on and burnt 150KM's......stopped a number of time ( on the top of hills) shut down and started again....I have not been able to duplicate the initial faults..the hiccup or flooding no start...something has changed I know not what but i will be checking the components I swapped out but my gut tells me it was probably a dodgy connection on the temp sensor or such.

thanks guys for the help and although it would be nice to know what it was, it is also nice to know I can jump on her anytime and she will start.

    

Yay for you.

I was going to ask you to come and get a photo with B2 and myself, but I didn't want to be sitting on the side of the road while you fixed your bike so I didn't bother calling you.

Glad to see the grey brick breaths live again Klompy .
Hey rossko it's just as well Klompy couldn't make it, or you would've  needed photo shop work to stop the rs showing up the basics. It could have been a rose amongst two reapers at St peters.

check this one out ..its red and i bet I could get it going...

http://www.ebay.com.au/itm/BMW-K100-RT-1985-WITH-31ST-JANUARY-2014-REGO-NOT-GOING-/171190460040

Glad you got it going mate. I swear that bike in the link has the seat off my first RS......

smithy wrote:Glad to see the grey brick breaths live again Klompy .
Hey rossko it's just as well Klompy couldn't make it, or you would've  needed photo shop work to stop the rs showing up the basics. It could have been a rose amongst two reapers at St peters.

Smithy as my 15 year old would say "Tru Dat".....................
Had her going by 1400 and had to blow the fuel out of the exhAUST....see what i did there....

well done Klompy and all. 
at least you know you've been through and cleaned a few other things , so should be all okey for a while.

got my fingers crossed for you klompy
good work

yeah wouldn't be hard that ebay one eh ?

Great to see that all is good again . You now know the importance of Good Connections.   This forum has them and now you have them as well.

Glad it's running!

Well done Klompmeister, if only you knew what was well done. Hopefully it's solved mate.

yep going great....first touch of the button and it fires every time ....am a little curious what it was but i will call that adventure a " major service"...and get on with it.
one thing for sure i now know how to get her pulled down and able to access most bits pretty quickly now.
Now know how to get the airbox out in a couple of minutes which gives great access to the temp sensor and fuel pressure regulator. Wish I had a lazy $1500 lying around I reckon that RT at Tuggerah could be going within an hour or so....no power to the injectors should be electrical only and I have all the components in that line ready to go....oh well.

Good for you Klompy.

I had a 'won't start' thing this morning, so the outfit is in bits. Can't get the upper air box out at the moment; the rubber connector is 'welded' to the AFM and the head of the screw to release the rubber from the plenum is right next to the fan housing.  

Be back at it tomorrow.

Paul.

here is the big hint with the airbox.....undo 3 x clips, take filter out, if you are fortunate all you need do now is tug outwards gently on the top and it may release from the induction trunks box over the Throttle bodies.

There is a clamp on this too but it is heaps looser than the impossible to remove one connected to the AFM.

as per the following which is what you will find in your hands ..

 

Thanks Klompy,
I'll try that tomorrow.

Paul.

When you put the airbox top back on, make sure that the screw faces up and back so that in future (and there will be a future need) you can manouvre a long screwdriver down from under the tank (lifted up) and get that
screw tightened. I also greased the rubbers a bit to help, prob get hammered for that but it works.
The AFM won't come out unless you undo the 2 little bolts on top and the electrical connector from inside.
Keep children away when doing this, they might learn some new adjectives.
RT

I put that hose clamp back on so that you can undo it from below.  That way you can reach in from the right side to undo it and don't have to mess with the tank to get the MAF out.

some times its a good idea to line up the screw to the plenum clamp  down and back a bit looking forward ..  you can always  access the under radiator section with a long screwdriver ...well I can,   that way I see whats happening all the time from the rhs  ...yes blind old bat syndrome
but I guess folks with belly pans have to explore different options like rts suggestion from the tank area

Managed to undo the screw today when Klompy's idea didn't work for me. It's never been off in 28 years so I suppose it deserves to be tight. I found a pressed steel 7mm spanner from my grandson's construction kit that was able to turn the screw about 30º each go; it just needed a bit of filing to get in.

Yes, turning the hose clamp round gives plenty of room to get at the screw from below, when it goes back together.

When the bike didn't start yesterday, I went through the usual checks; when I checked to see if there was pressure in the fuel line by squeezing the feed pipe close to the fuel rail, I got petrol on my hands, so that was the catalyst to change all the fuel lines, hence the removal of the air box. 

Whilst down there I've pulled the injectors, ultrasonically cleaned them, painted the bodies and fuel rail, all ready for new 'O' rings which should arrive tomorrow.

As there was no evidence of a fuel leak until I squeezed the petrol pipe, I still don't know why it wouldn't start yesterday. Be at it again tomorrow.

Paul.

I had to carefully cut the hose clamp off mine with a dremel. When reattaching I used a hose clamp with the screw turned 90 degrees to the original. Now I can easily access the screw.

Put it all back together today and it started as soon as the fuel lines and rail were full. Reset the bypass screws using my mercury columns and it's now running as sweet as a nut.
 But still not convinced I've solved the problem of why it didn't start on Monday.

Anyway, just for info, sensible position for clamp screw.
   

And silly position for clamp screw, (courtesy of BMW)