Fuel injectors: Clean or Buy new.

[BuddingGeezer]

I have just bought a 1987 K75C with 37K on the clock. The PO said last winter that he rode the bike , parked it, tried to restart and the bike never ran again. Would hit, but not run.

Timed Fire+compression+Proper fuel-air mix=running engine

Great Fire-timed??? I think so.

Compression, my guage woun't fit plug hole, but I think good.

Good fuel to rail. The fuel lnjectors do not spray, they spit tiny globs and not much at that. Believe this is the problem.

I have read recommendations for professional cleaning . Who does this?
Or buy refurbished or new?

Ralph Sims

[jdiaz]

Ralph, just go to a diesel fuel injection shop and let them try to clean them out. Its worth the $20/injector. I'm sure you have plenty of those places around considering all the trucks rolling by daily on I-30. :laugh

I would also try to clean out the fuel rail as well....its not hard for that thing to get rusty after 20 years.

[BuddingGeezer]

Thanks, I hadn't thought of that. The gas tank, fuel rail are spotless. No varnish anywhere. PO installed a new fuel pump. Injectors look like dirt on a white rag, though.

Right about the trucks, I 40 between Little Rock and Memphis is worse.

Ralph Sims

[RandyB]

Jon beat me to it, but aren't you about 500 yards from the interstate?

You're getting as bad about K bikes as I am airheads. I hope the GS will be fixed this week. We need to get one more ride in.

[guzzirider]

I just replaced 2 of my injectors on my k-100.I installed borg/warner 57056 injectors @ $ 52.00 apiece from a local parts house.I am going to send my 2 bad ones in to a injector service to recondition them @ $ 25.00 each.Then switch out the other two and have them reconditioned.

[breyfogle]

....I have read recommendations for professional cleaning . Who does this?
Or buy refurbished or new?...

I had mine cleaned and balanced by RC Engineering earlier this year. They are local for me but they accept mail-in work. A google search should find their website. FWIW, "RC Engineering" is actually Russ Collins, the Honda drag bike guru. They might be a bit more knowledgable about motorcyle fuel injection than a local diesel shop.

[BuddingGeezer]

I appreciate all the help. I did some cleaning on them with Berryman B12 this afternoon. I would fill the injector with a hypodermic needle, opened the magnet with a 12 volt sorce and let drain several times. Opened the magnet and shot carb cleaner through. Fuel is now flowing through them. I will try to find new o rings tomorrow and see if she runs. If The bike will run I have had good sucess running with Seafoam or Berrymans to clean the system on other engines.

I'll keep all informed.

Ralph Sims

[mrich12000]

I had mine cleaned and balanced by RC Engineering earlier this year. They are local for me but they accept mail-in work. A google search should find their website. FWIW, "RC Engineering" is actually Russ Collins, the Honda drag bike guru. They might be a bit more knowledgable about motorcyle fuel injection than a local diesel shop.Rermove the fuel door,:violin replace the fuel filter FIRST!!! Obtained mine from Mr. Injector Cotere' Idaho he is on Ebay 65.00 with shipping. Bike picked up like rocket after the injector switch. one thing have an arisol of carb cleans to spray the injector head points to rid the area of sand varnish and stuff.

:type CHECK ALL FUELINES FIRST MAKING SURE THAY ARE NOT DETERIATED
BIKE MUST BE ON CENTER STAND..
to do the change leave the pressure side connected disconnect the return side place a scott towel under the line
remove slowly have a clean 5/16 x2inch bolt handy to plug the return line.
rmove the 2 holdown bolts carefully wigle the fuel rail while pulling up from the head the injectors and rail should come out. note the position of the injectors . take pictures if needed, I did.

:fight look at the connector now with a fine pick lift the wire band connector holder and pull it back (note the injector leads)on the fuel rail there are clips that hold the injectors to the rail. Rmove one at a time. use a little engine oil on the "O" rngs topand botom then furmly push the injector back onto the fuel rail install the clip it should face the top and there is a postion for it to lock when all three are in place reinstall the connectors return the steel wirwe band wigle test the connector to see that it has seated return the fuel lin and secure, place the fuel rail onto the head push evenly the rail should push into the head . When that is done install the retaining bolts use new wire ties spray the head area double check . Looks ok turn on the key PLACE BIKE INTO ANY GEAR, DON'T START THE BIKE JUST YET.
PUSH START BUTTON THIS WILL PURGE THE INJECTORS.
place into nutral start the bike use the throtle choke should come to life rev up and down then let it idle
check for leaks GO FOR THE RIDE SHOULD NOTICE THE IMPROVMENT :bolt
there are other thing to do like throtle sync but that anothe tech story
it's late pardon the spillin..

Michael:german :lurk
VE3CEH
K75

Up the revolution Give Back Maine:usa :bolt :laugh

[BuddingGeezer]

OK guys here is where I'm at.

1. I made a device that allowed me to force cleaner through the injector with air pressure of 34psi. A 9volt battery opened and closed the injectors. Injectors have a good conical spray pattern.

2. New Bosch spark plugs installed, gaped at .028 and torqued at 15 ft-lbs and NGKs removed. Bike now starts and idles at 600-700 rpm. Starts quickly. Touch the throttle and engine immediately dies. No stumble, cough or back fire. Just dies.
3. Dead head fuel pressure at the rail is 100psi.

4. Fuel pressure at idle is 36psi (Clymer spec)

5. Fuel tank connector, fuel injector computer, HES, and ignition ignitor electrical connectors cleaned with contact spray, scraped, and dilectic grease.

6. I installed the throttle position switch from my K100, plug cleaned, no change.

7. Throttle body vacuum identical on all 3 throttle bodys. The reading was taken on an old gauge, probably not accurate but was 30% lower than my K100. Reminds me of retarded timing.

8. I can rotate the HES from lock to lock and there is very marginal effect on the idle.

I no longer believe this is a fuel problem anymore, but a timing problem. Can the HES cause these symptoms or would this be the ingnition ignitor??????????

What do yall think?

Ralph Sims

[wndsrfr]

The key thing that happens when you first touch the throttle is the throttle position switch clicks to tell the computer that it's beginning to open......do you hear the little click from the TPS (engine off) as you just barely open/close the throttle? If the TPS isn't adjusted right, the FI computer won't know to hit the gas as the throttle begins opening.......

[BuddingGeezer]

Yes, both throttle position switches were installed and adjusted to hear the click. I can eliminate that as the problem.

Ralph Sims

[BuddingGeezer]

The mass airflow sensor was not hooked to the rubber tube. I opened the butterfly by hand and the bike took gas. Problem solved.

The bike has a high pitch whine from the started alternator area?????????????

Thanks
Ralph Sims