I had a bit of a go at getting the K75 going on sunday. New fuel pump is installed and working, and it has spark, but the injectors are not firing, so no go. Its all 3 that dont squirt fuel, so the problem is somewhere in the circuitry that controls them. So where do I look?

Use the old screwdriver handle to your ear trick and listen for them clicking, this will make sure that they are opening or at least getting the signal.
If you have fuel pressure and can hear the click then pull the injectors and clean them.
If there is no click then there is a good chance they are stuck closed or the signal is not getting through. Make sure the multi pin plug on the ecu is pushed home and the contacts are clean.

RicK G wrote:Use the old screwdriver handle to your ear trick and listen for them clicking, this will make sure that they are opening or at least getting the signal.
If you have fuel pressure and can hear the click then pull the injectors and clean them.
If there is no click then there is a good chance they are stuck closed or the signal is not getting through. Make sure the multi pin plug on the ecu is pushed home and the contacts are clean.

I actually pulled them out to check. Absolutely nothing on all 3 so I'm thinking no signal as I'd expect at least 1 to show signs of life if they were stuck. Is there a relay in the box under the tank as well as the ecu

This is where he relays are. If you get Bert's flow chart it will guide you through the process.

phil you could stick your multimeter across one of the injector electrical connections and ground and measure if you have 12 volts on one of the terminals )key on )  I believe that the under seat ficu grounds the injectors whilst operating ...that might tell you if there is a volt supply issue further back into the electrics before much else

we know that the relays can sometimes be intermittent after all these years

good luck

charlie99 wrote:phil you could stick your multimeter across one of the injector electrical connections and ground and measure if you have 12 volts on one of the terminals )key on )

The starter button must be pushed or the engine must be running to make
the FI relay to operate and supplying 12V.

good point inge ...cheers

Rockman wrote:I had a bit of a go at getting the K75 going on sunday. New fuel pump is installed and working, and it has spark, but the injectors are not firing, so no go. Its all 3 that dont squirt fuel, so the problem is somewhere in the circuitry that controls them. So where do I look?

When I pulled down my first K100 I had the injectors out while I did the restoration.  The injectors actually sealed themselves up while they were out.  There was a varnish film on them that stayed wet while in the fuel rail, but once pulled out they sealed up and could not be saved.  It fired straight up once they were replaced.  I made a little test light from a red LED bulb to confirm power to the injectors.  I think crazyfrog may have pointed me in that direction.   I expect there is a page on it here somewhere...

club_c wrote:

Rockman wrote:I had a bit of a go at getting the K75 going on sunday. New fuel pump is installed and working, and it has spark, but the injectors are not firing, so no go. Its all 3 that dont squirt fuel, so the problem is somewhere in the circuitry that controls them. So where do I look?

When I pulled down my first K100 I had the injectors out while I did the restoration.  The injectors actually sealed themselves up while they were out.  There was a varnish film on them that stayed wet while in the fuel rail, but once pulled out they sealed up and could not be saved.  It fired straight up once they were replaced.  I made a little test light from a red LED bulb to confirm power to the injectors.  I think crazyfrog may have pointed me in that direction.   I expect there is a page on it here somewhere...

This might be the case so I'll have to test if I am getting power to them as Charlie suggested. The bikes been sitting dry for a fair while.

ive had some  great results from using white vinegar (as suggested by either .75 or laitch ...sorry cant remember ) recently

dump the injectors into a small bottle - jar  enough to cover the pintle area at least , 1/2 an inch deep  and let them soak overnight at least

havent tried the whole injector in the solution yet ...not sure its safe to do so , but my thinking is that it may loosen the sticky mass inside the injector holding the pintles ??

just a thought

Theres a 4-pin circular connector that joins the injector sub-harness to the main harness. This connector is similar to the fuel tank one, which gives many people grief. It's possible this connector is not mating properly and you won't get power to the injectors. Check and clean it.

I tried Charlie's suggestion of white vinegar with partial success. So far 1 have managed to get 1 of the three going. The other 2 are still soaking in it (Mrs Marsh was it?). Failing that can anyone suggest a cheap source for new injectors?

Update: After searching the forum and getting thoroughly confused I have purchased a set of 3 for a 5 litre ford falcon off ebay. At $57 all up I'm not much out of pocket it they dont fit.

I seem to have a collection of non-functioning injectors as well, so would be interested to hear your results and if there are original ones to be had somewhere.
Sean

I have got 2 non firing injectors working by taping them onto a copper bar to knock the pintle valve open and then they have performed OK.  A couple of others that I freed up when rust was involved have worn and were running rich. There is no guarantee but what have you to lose.
I clean them using dishwasher detergent in an ultrasonic tub then final flush with carb cleaner while holding 9 volts on the coil which stops it overheating which is what happens when 12 volts is used.

Rockman wrote:I tried Charlie's suggestion of white vinegar with partial success. So far 1 have managed to get 1 of the three going. The other 2 are still soaking in it (Mrs Marsh was it?). Failing that can anyone suggest a cheap source for new injectors?

Update: After searching the forum and getting thoroughly confused I have purchased a set of 3 for a 5 litre ford falcon off eBay. At $57 all up I'm not much out of pocket it they don't fit.

The 5 litre ford uses the same Bosch injector as the K100/K75 so it should be OK

A local workshop that cleans injectors told me they use lacquer thinners to clean theirs. I did give it ago in a Aldi sonic cleaner and it did eventually clean a couple of stubborn ones. However it didn't do much good with the lid on the cleaner, which softened to moldable condition. I now owe the Honorable Minister for Finance and Recreation a new jewelry cleaner.
Regards Martin.

Saxon7 wrote:I seem to have a collection of non-functioning injectors as well, so would be interested to hear your results and if there are original ones to be had somewhere.
Sean

G'day Sean
I cancelled the first order as I had misread the ad, but now have a set of 8 coming for $170. If they are ok are you interested in going halves? (4 each, I'll have a spare)

Yep that'll work. Let me know how it goes.
Sean

MartinW wrote:A local workshop that cleans injectors told me they use lacquer thinners to clean theirs. I did give it ago in a Aldi sonic cleaner and it did eventually clean a couple of stubborn ones. However it didn't do much good with the lid on the cleaner, which softened to moldable condition. I know owe the Honorable Minister for Finance and Recreation a new jewelry cleaner.
Regards Martin.

Sell all the jewelry and buy a big ultrasonic cleaner.

I have a large ultrasonic for cleaning records in and there is no way on this world a filthy dirty injector is getting anywhere near it.

But, my turn table is worth as much as my K 

New injectors showed up in the mail today, all 8 of them. Bosch 0280155844. I'll fit them tomorrow and see what happens

:like:There's a chance I'll be passing through Inverell on a loop from home to Glen on Sunday, ( if I manage to get  my uni stuff finished)
Will get in touch tomorrow evening to see if you're about.

Sean.

Saxon7 wrote::like:There's a chance I'll be passing through Inverell on a loop from home to Glen on Sunday, ( if I manage to get  my uni stuff finished)
Will get in touch tomorrow evening to see if you're about.

Sean.

Yes do that. I'll bung these in the K75 tomorrow. In theory it should run straight away.

EDIT: And it did - purrs like a Kitten. Full service now and get it back on the road. I have about 3 fairing sets to choose from, and 4 seats, 3 screens etc so I'll have to sort through them and select which I want.

Probably a bit late now...

Search on youtube for DIY injector cleaning. Problem is that once cleaned, the flow rate might still be out unless measured.

Of course, you can buy injector service kits easily and cheaply enough.

One thing I do when "servicing" mine is to reverse flush the injector. Unless the filter is replaced on the top (use a self taping screw and pull it out) there will be debris / shite in it. A reverse flush blow it back out of the top. 

Haven't worked out a good way to measure flow rate... some of you more able fabricators can work out a device that:

Uses a piece of circular wood (eg hole saw) attached to a drill on #1 speed / or drill press geared down
One the edge of the wood attach a piece of very thin metal sheet to create an eccentric edge
When spun around, the thin metal sheet creates an on / off switch for the circuit...
Circuit = 9V battery, wired to a fuel injector (alligator clips)
Top of the injector uses the tire valve, pressurised carby cleaner and straw (on youtube)
Cleaning continued accurately over say a minute and output / flow rate measured into a container.

A small piece of board could be used to secure all the bits and pieces

So at this stage of my reply, I looked on youtube and found:

https://www.youtube.com/watch?v=wF0zQCkbIr0
NB: I don't think injectors are meant to be on for too long
Note comment about using a digital scale to measure weight

I still have a bag of bits from Jaycar to mount a small motor to imitate the on off action of real life. 
One day!!

GF

Rockman wrote:

Saxon7 wrote::like:There's a chance I'll be passing through Inverell on a loop from home to Glen on Sunday, ( if I manage to get  my uni stuff finished)
Will get in touch tomorrow evening to see if you're about.

Sean.

Yes do that. I'll bung these in the K75 tomorrow. In theory it should run straight away.

EDIT: And it did - purrs like a Kitten. Full service now and get it back on the road. I have about 3 fairing sets to choose from, and 4 seats, 3 screens etc so I'll have to sort through them and select which I want.

good to hear mate

love to hear a ride report when you get it down the road

In order to test injectors and flow rates you can get a injector tester off Ebay or Alibaba. https://www.ebay.com.au/itm/EM276-Injector-Tester-Fuel-Injector-4-Pluse-Modes-Tester-Fuel-System-Scan-Tool/112837522316?hash=item1a45a3f38c:g:rngAAOSwQbhak8mM The unit will pulse the injectors at various rates. I use this in conjunction with a 250ml graduated vessel.  Original home made tester worked but the commercial version was better.I also built a rig to pressurize the injectors using air from my compressor which can be adjusted to supply the correct pressure. Pictures are a guide the unit has changed slightly as lessons were learnt. Be very careful when testing injectors on the bike as if you are not extremely careful fires can result. KABOOM. Have a fire extinguisher.
Regards Martin.
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