I jut came across this diagnostic/fault code check procedure.

http://www.k11og.org/forum/viewtopic.php?t=2110&postdays=0&postorder=asc&start=0

Seems like a good place to start.

Too much fuel how do you know ??? are the plugs wet,?? excess  fuel runnning out of exhaust??.Have you followed the FORUM new to me Ks how to.

chris4n6 wrote:So it's evidently getting way too much fuel.

As moriarti is suggesting, if the spark plugs are wet after this machine splutters and dies, it might be getting too much fuel or it might be getting too little spark.  If dry, it might be getting too little fuel.

If you haven't done this already, you should clean the main ground connection on the frame backbone under the tank and all the terminals connected to it, then clean every electrical plug connection with DeoxIT D5 and all plug wire connections and coil terminals if they haven't been cleaned already. The fuel filter should have been replaced by now and all interior hoses checked for tight connections and leakage.

moriarti wrote:Too much fuel how do you know ??? are the plugs wet,?? excess  fuel runnning out of exhaust??.Have you followed the FORUM new to me Ks how to.

Too much fuel is a conclusion based on the following. Injectors seem spray a lot of fuel, when tested out of the bike. And with the fuel pump plugged in it won't start but will pop and sputter (muffler smells like gas), but as soon as I unplug the pump, it will start, and run for about 5 seconds. If I then plug the pump back in, the same process repeats.

I haven not checked the 'new to me k's forum. I will do that.

Thanks,
Chris

Laitch wrote:

chris4n6 wrote:So it's evidently getting way too much fuel.

As moriarti is suggesting, if the spark plugs are wet after this machine splutters and dies, it might be getting too much fuel or it might be getting too little spark.  If dry, it might be getting too little fuel.

If you haven't done this already, you should clean the main ground connection on the frame backbone under the tank and all the terminals connected to it, then clean every electrical plug connection with DeoxIT D5 and all plug wire connections and coil terminals if they haven't been cleaned already. The fuel filter should have been replaced by now and all interior hoses checked for tight connections and leakage.

I will check all grounds and Deoxit all plugs. Thanks!

Fuel pump filter and hoses are new.

Hall sensor unit needs testing to prove spark performance .Just to give a point to start from

While I agree that the Hall Sensors can be a problem area, in this case watching the video of the bike starting up (without radiator etc) would suggest they are working.

Mike

When you say new hoses, did you replace the crankcase breather hose(AKA the infamous "Z" tube)?

On a bike that has been idle in extreme conditions it is not unusual for that tube to get cracks at the clamps.  The air leaking will make it difficult for the engine to idle smoothly if at all.  If you haven't replaced it already, do it before any serious troubleshooting.

A quick check is to remove the return line to the tank and run it into a jug.  That will let you know if the plumbing in the tank is back pressuring the regulator and give you an idea of when the pump is running and how the flow is doing. 

Aftermarket injectors may be a problem.  I bought a set on eBay that made the engine on a bike I was restoring run like crap.  I replaced them with a set of used OEM injectors to get the engine running properly.  There are repair kits for injectors that will replace the filter screens, o-rings, and pintle caps for a set of injectors for less than $15.  There are also injector cleaners that will open the pintle so you can blow cleaner through.  I have had pretty good luck refreshing old injectors with one of these kits and a can of cleaner.

Chris4&6,

You posted a link to a diagnostics page which was for Motronic equipped bikes (4 valve K100 and K1100). Your 2 valve K100 is equipped with the earlier Jetronic system.

Things like the water temperature sensors are different and ECU pin outs are different. Don't want you chasing your tail.

Mike

mike d wrote:Chris4&6,

You posted a link to a diagnostics page which was for Motronic equipped bikes...

Doh... Thank you!

Agree with point seven five, the barb for the fuel return hose might be blocked with dirt and rust. Another quick check is to attach a hose to the barb, then try to blow air into the tank. If you can't then the barb is blocked. 

Another thing to look at is the temperature sensor. If it's dirty (like a some of the other bits) clean it, that might be the problem. The dirt could provide an earth path giving a false signal to the computer resulting in a rich mixture.

It dies at idle after five seconds with the pump unplugged. Does it continue if you give it plenty of revs? If so the injectors might be constantly open. When you looked at the spray pattern was it a series of pulses (it should be) or a constant spray?

Better place to start for a 2V; https://www.kforum-tech.com/electrical/EFI/bike-wont-start-EN.htm

Point-Seven-five wrote:When you say new hoses, did you replace the crankcase breather hose(AKA the infamous "Z" tube?)

A quick check is to remove the return line to the tank and run it into a jug. 

Aftermarket injectors may be a problem. 

1.) No, and I know for a fact that it's cracked. Totally forgot about that until you mentioned it now. 

2.) We did that prior to the engine teardown, probably worth doing again just to double check.

3.) I think my original ones are too far gone, but I will set up a test stand. See what I can do.

mike d wrote:While I agree that the Hall Sensors can be a problem area, in this case watching the video of the bike starting up (without radiator etc) would suggest they are working.

Mike

 YES I SHOULD HAVE WATCHED THE VIDIO

After it fails to start pull the spark plugs, are they wet or dry? Earth the spark plugs and check for a good spark on each plug. If wet and a good spark  check the temperature sensor and it's connections they can go bad. Clean the connections and test the sensor using a cup of boiling water a thermometer and a multimeter.

So we had a problem with Vic bike which was over fuelling and soaking the plugs 
the Water Temp sensor tested out ok 

But Dai lead us to a connector under the tank on the rear left which somehow while the two parts were plugged together one of the conductors  inside had been dislodged and pulled back enough to break the connection

MartinW wrote:After it fails to start pull the spark plugs, are they wet or dry? Earth the spark plugs and check for a good spark on each plug. If wet and a good spark  check the temperature sensor and it's connections they can go bad. Clean the connections and test the sensor using a cup of boiling water a thermometer and a multimeter.

Thanks for the chart. Because it runs with the fuel pump unplugged, I'm going to assume the other things are not an issue for now.

Because it is running really rich it will run with the pump disconnected on the fuel left in the combustion chamber and then die as the residual fuel is burnt up. It has happened to me twice and in order to get home I pulled the fuel pump fuse started the bike and as it died I rammed home the fuse. It managed to get me home with throttle manipulation albeit running rough.
Regards Martin.

In your first video, the bike eventually fired up and ran (4.14 in to 4.54). It looked to me it only stopped when the throttle was closed. Perhaps you disturbed something else when reassembling from that point onwards?

Mike

mike d wrote:In your first video, the bike eventually fired up and ran (4.14 in to 4.54). It looked to me it only stopped when the throttle was closed. Perhaps you disturbed something else when reassembling from that point onwards?

Mike

Yes... We have considered this at great length :-) On one hand, it's super frustrating. On the other hand, it's provided us with the hope to continue haha.

I have tried to work backwards through what we did after that initial run, and the only thing we can come up with that we haven't been able to check yet, is the temperature sensor. It is in water now, and it wasn't during that first run. Because there are so many unknowns with this bike, having been idle so long (pun intended), last night we started a list of things to test/clean/do before we try again. For example, I know the grounds aren't as clean as they need to be. Also, the crankcase breather is completely deteriorated.

You are to be applauded for the amount of work done to get to this stage, dropping the whole motor out etc, so I am sure once the obvious things are checked, like the water temperature sender, crankcase breather progress will be made.

Keep up the good work!

Mike

I would sort the Z pipe and temperature sensor, not being in water or liquid means it's not giving a correct reading which can over fuel. Disconnecting the fuel pump leans out the mix and lets it run. Don't use ptfe tape if you remove and refit the temperature sensor.

mike d wrote:You are to be applauded for the amount of work done to get to this stage

Honestly, I was ready to scrap it once I saw the condition of the the head/valves! 

But few things compare to the drive of a 15-yr-old who was give a free motorcycle. Also, a friend of ours told him, "that thing will never run." So he has an intense need to prove him wrong :-)

You need to really believe the K engines are unburstable. 100,000 miles is nothing to them. Like anything made there are a couple of potential issues to be aware of but the forum here covers them all. I am 12 years in K bikes and just love them.

Not that I can compete with the knowledge above...
FWIW...
Have you swapped fuel pressure regulator under tank? Will need to remove air filter assembly (filter and base).

GF

GF Wollongong wrote:Have you swapped fuel pressure regulator under tank? Will need to remove air filter assembly (filter and base).

Since I posted this topic, we have decided that the regulator is indeed bad. When sucking on the regulator vacuum line to depressurize the system, there is almost no resistance, and it still seems like there is still pressure when we take off the lines.

Unfortunately, when we had the frame off, the lower air box bolts were so rusted and stuck that we just left them be.... a decision we are regretting now. We have a few ideas of how to get them out, some of which may damage the lower air box - but we'll see!

Thanks for the suggestion!

More conclusive, though possibly not as pacifying as sucking on a vacuum line, is doing a fuel line pressure test with equipment you can borrow at no cost from NAPA, Pep Boys, AutoZone or some of the other major auto parts dealers. All you need is to leave a fully-refundable deposit. Do it now while everything is still connected. Instructions can be found in this link at the end of the document.

Laitch wrote:More conclusive, though possibly not as pacifying as sucking on a vacuum line

"not as pacifying" LOL!!

One source - cant remember if it was the clymer manual or somewhere else - said the first diagnosis step for the regulator was to apply a vacuum to the hose and if air hissing can be heard, it is faulty. If that is the case, ours is definitely faulty.

Chris4n6 wrote:

GF Wollongong wrote:Have you swapped fuel pressure regulator under tank? Will need to remove air filter assembly (filter and base).

Since I posted this topic, we have decided that the regulator is indeed bad. When sucking on the regulator vacuum line to depressurize the system, there is almost no resistance, and it still seems like there is still pressure when we take off the lines.

Unfortunately, when we had the frame off, the lower air box bolts were so rusted and stuck that we just left them be.... a decision we are regretting now. We have a few ideas of how to get them out, some of which may damage the lower air box - but we'll see!

Thanks for the suggestion!

Just get a replacement lower air box and have it to hand. Should be easy to get as there is no demand for them. . . . . apart from those that have to break it out to get those bolts out.

I had as similar issue with those two Allen bolts. If you haven't gouged them out liberal WD40 over time did the trick for me using an Allen key and an extender on it. It's not hard to get at them. If you take out the air filter and wedge the top half up out of the way you can get longer Allen keys in. I use copper paste on them when I put them back and don't torque them up much. I have developed a habit of backing off potential troublesome bolts from time to time and retightening and it seems to work ok. Give them a lot of time, there are rubber washers on them but you will get it to work.

There is no compulsory need to mount the new regulator in there although it is a good and out of the way location. A few have moved it, just need to alter the fuel line hoses which you should be renewing anyway. If you are pulling the radiator to get at the temperature sensor you can get at the fuel pressure regulator.

92KK 84WW Olaf wrote:
I had as similar issue with those two Allen bolts.

If you are pulling the radiator to get at the temperature sensor you can get at the fuel pressure regulator.

My allen bolts were so rusty that the allen sockets are just round :-( We're going to try a 'lug nut removal socket' first, then if that doesn't work, we're going to weld a nut to the top.

We are pulling the radiator for the temp sensor!! Thanks for reminding me. I forgot that we can access the regulator that way!

One of the mods I have been promising myself for about 4-5 years was to relocate the pressure regulator.

The forum's founder, Bert, AKA Crazy Frog moved one of his regulators to the front frame downtube just above the #1 cylinder.  Not only did it make all the fuel and vacuum plumbing more easily accessible, but by moving the regulator from the space directly behind the radiator, the heating of the fuel and the tank was reduced. 

https://www.k100-forum.com/t15210-relocating-the-fuel-pressure-regulator

If you go that route, there is no need to remove the old one other than to remove a couple ounces of unnecessary weight.

moriarti wrote:Too much fuel how do you know ??? are the plugs wet,?? excess  fuel runnning out of exhaust??.Have you followed the FORUM new to me Ks how to.

Hi Moriarti,

I looked around for the 'new to me Ks' forum, and I'm not seeing it. Can you help me out?

Thanks,
Chris

http://www.verrill.com/moto/newkbike.shtml

-Dai

Dai wrote:http://www.verrill.com/moto/newkbike.shtml

-Dai

Thanks!

So, my son comes to me yesterday - after he took the air box off to access the pressure regulator - and says, "you know the plug for the air flow sensor? It wasn't plugged in."

Often it's the simple stuff that, when overlooked, leads you down a rabbit trail of frustration...

Where were at now:
New temp sensor installed.
Fan motor bushings lubed and no longer squealing. 
Air flow sensor plugged in (I'm sure this will help!)
New external fuel lines 
New pressure regulator vacuum line (leaking)
New crankcase breather 


To do:
Reinstall radiator
Clean ground connections
Deoxit plug connections
See it it'll start! I'm hopeful this time! :-)

After that:
Joy ride!
Address gas tank pinholes. (Started weeping through epoxy)
Change oil/filter
Inspect rear drive line
Brakes? (Rear reservoir was hanging upsidedown and empty)
Lights
Body panels and fairing

We're making progress. Thanks for all the help and support!

By the way, the lower air  box bolts that were too rusty to remove with an Allen wrench were easily removed with a Amartisan bolt and nut extractor set - $30 from Amazon. First time I ever used them. Worked great! Recommended. Heard about them on the Project Farm YouTube channel.

It seems like it's almost always something really stupid simple.  Good to hear you found the problem.

Project Farm is good.  No bullshine reviews of useful stuff.  I like the guy's approach and the way he presents his information.

Thanks to everyone for helping us get our issues resolved! My son got his first ride today and he was THRILLED! Very high 'smiles per gallon.' :-)

The plug in the MAF can be a RRPITA when you start pushing the wiring loom around to get at the air filter. In theory, it's securely anchored. In practice...   When working on the early K's I chop through that section of the loom and fit a four-way plug. Makes life easier all ways round.

If you feel so inclined, here is full update including the first ride. It's amazing how easy it started once everything was plugged in!  

Well Done bring another one back to life