My BMW K100
RT (1985 vintage) has been off the road in my garage for about 5 years whilst I
slowly repaired the fairing. This is now complete but I am now having trouble
starting the engine. Having stood for 5
years I assumed that the petrol had gone stale so I drained the tank and put
some fresh fuel in. I have checked the battery connections as in the past I
have had trouble with K100 and K75 starting due to poor earth connections and
semi flat batteries. I have currently got it connected to a Metro car battery-
fully charged. I can hear thye fuel pump running, and if I remove the rubber
hose from the rear of the fuel rail there appears to be plenty of pressure
here. On taking the spark plugs out I am getting a nice bright spark but I noticed
that the plugs are bone dry- indicating that no fuel is being spat into the
cylinders.





At this
stage I checked out Crazy Frog’s very useful fault finding chart and tips. I
have placed a led (in series with a 470 ohm res) across the end injector and
this flashes once per revolution as it should. I have checked out the voltages
expected at the connector to the fuel injection computer and the only anomaly I
can see here is that when I turn the engine over the signal at pin 4 (starter
running) reads 8 volts whereas in Bert’s table this should read 12 volts. I
have had an exchange of e-mails with Bert and he assures me that this voltage
is not critical. The ground to injectors
resistance at pin 12 reads 4 ohms, as it should with four injectors in parallel
across this line.





So at the
moment I am down to removing the injectors- which of course involves removing
the lower half of the RT fairing again.
I thought it worth raising this problem on here in case anyone knows any
common starting problems with K100s after they have been unused for 5
years? The bike started and worked
perfectly well after it was driven into the garage all those years ago.





Any
suggestions please?

A quick update here as I have had some time to get out to the garage today. I have taken the lower fairing panel off (again!) so that I can get access to the fuel rail/injectors. According to the Haynes manual it should be a simple case of just removing the two securing bolts and withdrawing the fuel rail complete with the injectors. But the injectors do seem very stuck in their holes. I'm reluctant to use too much force to remove them but is this normal? The injectors appear to move left to right and back and forth but they will not come out of the block?

Another quick update.
I managed to get all the injectors out complete with the fuel rail. I turned the engine over buy no fuel was being spat out by injectors. Took one injector out completely and attached a blown up party baloon to the fuel rail end with a tight tie rap. I then energised the injector with a separate 12volt supply- the injector made a clicking sound but no air from the baloon was emited from the injector. Could all four injectors be gunged up inside?

Hi,
I think you have hit the nail on the head, the process you followed was excellent and led you to the point where you know that the injectors are receiving operating pulses but they are not opening. I suspect all four are blocked and your options are to clean or replace.

An injector service company should be able to clean them. Last thing you could try is to get one cleaned and verify that works or borrow a known good injector and try that, if the good injector has power and earth it should spray when there is fuel pressure.
Regards,
K-BIKE

Hi K Bike,

Thanks for your response.

The only nagging doubt I have is that would all four injectors be bunged up? Could it be that the pressure from the blown up balloon would be insufficient to prove a real test. Certainly when all four injectors are connected to the fuel rail there appears to be plenty of fuel pressure but without a manometer, as suggested by Bert, there is some doubt.
The other course of action I might check out tomorrow is that the earth to the fuel pump is ok. If this went slightly high resistance the fuel pump might be turning but not producing sufficient pressure in the fuel rail.

Infact looking at the tax disc it ran out in 2003- so it has been off the road for six years, not five as I first guessed.

make sure the garage is using fresh new injector cleaner, I was told by a motorcycle guru that it does make a difference, using old stuff is just as bad as not getting them cleaned. good luck! b

Hi Mi Amigo

I have had a slightly similar situation aand sent off my injectors to my nearest injection specialist (@,000kms away!). I was slightly sceptical having read most of the reports that you have aslo read.

They utrasonically cleaned, replaced filter baskets(?) pintle caps(?) and seals. It cost AU$140.00.

THe results were great with better idling and a bit more response and power.

If your bike has been sitting for 6 years it could well be they are clogged. If not it may be worth getting them cleaned anyway...

If you get stuck I have a spare set of working injectors (they were working while set#1 got cleaned) that we could probably work something out with..

Regards

Mal

Thanks to K BIKE, Bruce and Cablebeacher for your replies. I have now taken all four injectors out and have sprayed some isoproponyl into the injectors. Interestingly, whilst doing this I stabbed 12volts across the coils and the isoproponyl dribbled out of the bottom of the injectors in harmony with the clicks of the internal solenoid. So I still have my doubts about whether my baloon test was a valid way of checking them, though I can't see why the air from the baloon wouldn't come out of the injector but the liquid did. Anyway I guess there is nothing to be lost in sending the injectors away for cleaning and from Cablebeacher's account it gives better performance afterwards even if they are not completely gunged up beforehand.

I have found a company here in England called Boxer Motor Works in Ashford, Middlesex. They are reasonably local to me. Has anyone used them here or can anyone reccomend another injector cleaner in London?

I have spent the morning cleaning up the earthing point under the tank and have left some isoproponyl in the injectors to try and clean them out.

EDIT:
Just phned Boxer Motors and they charge £85 incl vat to clean four injectors so I reckon that's worth a punt.

Hi There if isopropyl alcohol went through when powered I am surprised you did not get fuel squirting out when they were on the fuel rail and were powered. How about trying that test again making sure the sidestand is up (if you have got the side stand switch) because that cuts injection off when it is down. Do the checks before you spend 85 quid is what I suggest. Let the fuel squirt out and see what the patterns look like.
Regards,
K-BIKE

Hi K-Bike

It was a bit strange. Anyway I took all four injectors over to BoxerWorks near Feltham yesterday and they called today to say they were ready for collection. So I niped over on the K75 and picked them up. Before they do any work on the injectors they do give them a preliminary test on the bench which revealed that they were working fairly normally. Sio the pressed ahead and changed the gause filter and the prittle ends and giving them a further test after a clean-up revealed littlle improvement over what they were like before.

So I brought them home and had them fitted inside 20 minutes. I firstly turned the engine over with the injectors connected to the fuel rail but not fitted in the cylinders and they were spraying fuel nicely. Infact the spray must have been sucked into the cylinders as the bike was trying to start!

On refitting the injectors the engine started on the first turn!

I can only assume that the isoroponyl I had initially sprayed into the injectors had cleaned out any blockages- or maybe the new gause filters cured the problem. Either way I'm dead chuffed to get it running. Now I've just got to nurse it through an MOT.

I can thoroughly reccomend Boxer Motor Works at Ashford Middx for a quick and friendly service should your injectors need cleaning. The cost was £85 for four injectors.

Just one tiny problem left now- apart from getting the bike through its MoT.

I
have a piece of rubber left over from dismantling the fairing which I
can't find a home for. Any ideas where this is supposed to go- it's
obviously part of the fairing anti-vibration scheme:



Finally, many thanks once again to the contributors who have offered helpful advice on thos message board. I will continue to look in and hopefully offer and helpful tips to others in the future.

Sorry the photo only shows two ends, can you resend with all of it showing.
Regards, K-BIKE

Hi KBike

Right click on the picture and click on view pic.

I think it is a rubber spacer that fits between the injector rail and the fairing. I can't find a picture of it in the Manual and to take a photo of it on my bike I would have to take off the bottom fairing over the injectors and the internal fairing black bit... (its Saturday and I'm a bit lazy????)

I think it is part #14 /15 below. I don't know that it has a real purpose... I think the one you have has a couple of chunks missing from it.
Regards

Mal

Or is it this bit *6 from the air box???

Looks like the airbox piece (6). Looks like I will have to take off the r/h lower fairing to fit it.Thanks Cablebeacher.
For some reason only half of the picture came out. You have to right click on the picture and select "view image" to see it all.

Part 14 in your first picture appears to be either missing or wasn't fitted. I think the purpose of all these bits of rubber is to reduce vibration transmitted to the fairing or generally reduce 'resonance'.

Hi Mi Amigo, I read on another forum that piece is crucial to reducing the heat reaching the rider from the engine. I have my doubts about its effectiveness but the comment came from someone vastly more experienced than I.

Regards,

Phil

Well I've fitted the rubber where I think it should go but I'll leave the side fairing off for the rest of the weekend incase someone comes back with an accurate description of where it should go. It is currently on the R/H side, goes over the top of the air box and the bit on the right goes around the air intake from the front of the fairing.

It's part of '6' above; just had it in my hands today whilst building up the bike again.

ReneZ wrote:It's part of '6' above; just had it in my hands today whilst building up the bike again.

Where did you put it?

It looks like #6 the Airbox rear seal. The smaller end would be up and to the outside of the bike, while the larger end would be inside and bottom. It is positioned almost vertical at the rear end of the airbox. So the (6) in the pic would be under the tank and frame and directly under the (6) would be engine case, with the fuel rail to the right in the pic shown. Mine was held inplace with zip ties to the underside of the tank, but I don't know if that is the correct way to mount it. It works!

Luck!

Steve

It is a bit of insulation that fits over the airbox. On your picture it is upside down. The part with the little recesses on the right top in your picture fit around the bar of the butterfly valves and the fuel line coming from the pressure regulator. The shaped part on the inner side is all fitted around the airbox. This should prevent air going further aft (and heat up the rider) instead of being deflected sideways. The drawing shows it exactly as it should be fitted. The top of it (bottom in your picture) rests against the plastic bottom of the connectors etc between the frame tubes.