1985 K100 RT That didn't run...does now with issues!

[rbm]

That sounds like it is within spec.

[Supershooter]

Reinstalled the sensor, with dexoit, on connections, tested fuses, applied dexoit, dexoit on the fuel tank electrical connection, I’m charging the battery. I replaced the fuel return fitting going into the tank because it was corroded. Should I finish reassemblly and try to start or is there something else I should test?
Supershooter

[Supershooter]

Since the water temp sensor tested within spec, what should I check next?


Supershooter

[Timbox]

I did't notice in your trouble shooting if you removed the radiator?  I was just wondering if you flushed the system and look at the thermostat as well? 

[The Mighty Gryphon]

I did't notice in your trouble shooting if you removed the radiator?  I was just wondering if you flushed the system and look at the thermostat as well?

Excellent point!  Bricks don't seem to have a lot of reserve capacity in the cooling system.  My K100RS16V puked coolant almost everytime I took it out when the temperature was above 80F.  Somebody ran well water in the system and plugged it up with a lot of mineral deposits.  They also put on a lot of miles driving through bug swarms.  The heat melted the brush holders on the fan motor.

Soaking the radiator internals with vinegar a couple times cleaned out the mud and doing the same on the outside dissolved a lot of the bugs in the fins.  A couple cycles with radiator flush to get the engine passages cleaned out and the engine runs at the proper temperature regardless of how hot it is.  It only rises when stuck in traffic on hot days, and the new Spal fan handles that nicely.

[Supershooter]

Tim,
I am stumped on why the bike won’t start, so after getting it to run last Feb, i ran it through most of the summer and now it won’t start. I’ve written about my issues earlier i this thread. So I’m looking for
 Why it won’t run. Any help would be much appreciated.


I changed the coolant recently, and drained it before deciding not to r[size=78%]emove the radiator for this temp sensor project. So at this point I’m wonder if reassembly and hitting the starter is my best option or if there are more obvious this to rest. [/size]
[/size]
[/size][size=78%]Supershooter [/size]

[Martin]

You need to get back to basics. After failure to start pull spark plugs are they wet or dry.
Regards Martin.

[Laitch]

Because you have it stripped, you might check the vane in the mass airflow sensor and also its electrical connection. Look at the illustration of it in the K100 troubleshooting guide to understand how it works. The vane should move smoothly on its axle. There is also a test for its function in the guide.

This starting trouble is a classic K-bike syndrome on neglected bikes—and occasionally on well-used ones, too. It exercises patience, that's for sure. Regularly, somebody who has tested systems all over the place will eventually find the problem arose from a simple disconnection or failed hose that was overlooked. There is an owner working on the K100-forum now with a similar problem.

Do a Google search using this term.  doesn't start site:motobrick.com 

Go to the last few posts of each thread to learn how a problem might have been solved. Many problems were caused by simple, faulty connections, either mechanical or electrical. It's important to carefully read response here to the problem. In August, advice to check the fuel return line was given but not heeded until January. There likely could be several conditions contributing to this problem but there also could be just one.

Patience and thoroughness should be enough to solve it. Like Martin has observed, keep the basics in mind.

[Supershooter]

I appreciate all the advice! Since I'm a cattle dietician by trade and weekend motorcyclist, my mechanical ability is not always adequate. I'm staring to wonder if being a brick owner is really a good idea for me. At this point I'm going to regroup and continue to get this old brick running, but would really like a bike that'll be reliable once it's running. I'm a better to fix the problem guy than go figure the problem out guy, so if you'll bare with me, I'll try not to ask too many dumb questions. Thanks agin, I appreciate all the help.

[Laitch]

I appreciate all the advice!  At this point I'm going to regroup and continue to get this old brick running, but would really like a bike that'll be reliable once it's running.

Your persistence is admirable.

Motorcycles can be alluring enough to overcome better judgement. They are brilliant machines the workings of which are much more exposed to elements than cars and trucks. Despite that exposure, most can take hard usage if they get regular riding and maintenance. Regular riding dries the works and retards corrosion of electrical components. Regular maintenance—including washing—allows the mechanical parts to fully function.

It seems many prospective K-riders riders here don't realize that a neglected bike is likely to be a nest of problems, despite the site's being filled with anguished stories of their sometime costly and time-consuming challenges. If the purchaser of a neglected bike has undeveloped mechanical skill to attend to those problems or constraints on time to remedy them, frustration is usually the result.

Patience, persistence, self-education and often unexpected expenses are needed to get a neglected bike back on the road. With some bikes even that isn't enough. Those bikes are the ones that might be sold with ads reading, Ran well when it was parked a few years ago. Needs a tuneup and should be good to go.

You'll most likely get this bike underway with the help you get here and from other resources. How reliable it will be is a matter of how thoroughly you have pored over its systems, and luck. The best chance of getting a reliable ride that isn't labor-intensive or high-maintenance is to understand all the advantages and quirks of the type of bike that is wanted and to buy one that has been well-ridden throughout its recent ownership.

Keep asking and we'll keep answering.

. . . so if you'll bare with me . . .

Disappointing as it might be, I intend to remain clothed, here anyway. :giggles

[The Mighty Gryphon]

I'm a better to fix the problem guy than go figure the problem out guy, so if you'll bare with me, I'll try not to ask too many dumb questions.

I'll need to pass on that...

[Supershooter]

The master cylinder is leaking and I'm not sure where it's coming from, are the internal parts that need to be evaluated or show the master cylinder be renewed?


Can the ecm be bench tested at home or at a dealer?


The alternator wasn't charging the battery when I tested it. Should I go ahead and replace it or do more tests need to be ran before renewing it?


I'll start a log of what's done and tested and what needs to be tested, I hope it doesn't take too much more to get her running again.


Supershooter

[Martin]

The brush diode pack is easily removed to check and or replace, without removing the actual alternator. There are kits for the master cylinder available. However the internal condition of the master cylinder needs to be assessed to see if the bore is scored or pitted. Light marks can be honed out, deep scores or pitting will call for a replacement. Secondhand ones are available but might need a kit. You can get them sleeved but success rate in the US seems to be variable. We have a local guy who does them and tests and guarantees his work, cost is $200.00 AU. A rebuild kit should you need  it down the track will set you back $10.00 AU. He will ship overseas but you need to ship him yours. With all the shipping it could get expensive. Gryph had trouble with the sleeving he had done in the US so I probably would avoid that guy.
Regards Martin.

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[Supershooter]

Thanks Martin, [size=78%]I'll check into the diode testing, and mc kits. [/size]
[/size]
[/size][size=78%]I spent more time in the shop since the last post, just to prove to myself I hadn't fixed anything I hooked up the tank, charged the battery, and tried to start the bike, no go. [/size]
[/size]
[/size][size=78%]So I pulled the spark plugs and found them to be wet after attempting to start the bike. So with this discovery would I conclude that I have fuel, and am lacking spark?[/size]
[/size]
[/size][size=78%]Supershooter [/size]

[Martin]

You can have spark and fuel and it can still fail to fire. A faulty temperature sensor or connector can cause an overly rich mixture which causes flooding and failure to start. If you get stuck by the side of the road you can get them to fire by removing the plugs and let the engine dry out for 15-30 min. Alternatively remove the fuel pump fuse No 6 marked as Krafftestoppe or unplug the fuel pump. Replace the plugs and start the bike it should run on the residual fuel left in the combustion chamber. As the engine starts to die ram home the fuse or reconnect the pump. With a bit of throttle manipulation you can keep it running albeit roughly. Two people make the job easier but it can be done with one. If you can start it with this method try cleaning the connector with DeoxIT. If that doesn't work test the sensor's value with a multimeter.
Regards Martin.

[Timbox]

SuperShooter,

Way to stick with it!

After re-reading the thread and seeing the you used compressed air on the the fuel lines, is it possible that you might have blown something into the injectors?  I know you had them sent out and pro cleaned, so you know they were good when you installed them when they got back.  But when you were playing with the fuel system, did you flush the lines after hitting them with air?  I bypassed my fuel pump from the starter button and just wired it to a batter to "flush" the system without letting the injectors fire.  I was hoping that anything that was in the fuel lines or fuel rail would be pushed into the tank.  I had lots of old nasty gas, varnish and other stuff.  Once I was satisfied that my gas and fuel system was clean I tired to start the bike, it took a while but it did start. 

If my chance there is too much fuel in each cylinder, blow them out with some compressed air and try again.  Looks like even when you had her running it was not running well and or not idling well.  How was the roll on throttle response, was it smooth or was it stumbling?

Take the plugs out, dry them with compressed air, dry each cylinder and then try it again.  I really think you will get her running.  Once you do then work on the battery charging issue. 

With the wind and storm on the way, just stay warm and walk away when needed.

[Supershooter]

Martin, I'll plan to try the solution you suggested, hopefully this weekend.


Tim, the compressed air could have blown some debris back into the tank through the check valve ( I only blew air through check valve into the tank), but I'm hoping the fuel filter and strainer will prevent it from getting to the injectors. The issue I had when the bike ran was throttle response during roll on or responsiveness of acceleration. I the bike ran down the road at 55-70 without any effort, and idled well.


The plugs all look the same when I pulled them out.




Supershooter

[Timbox]

Suppershooter,

I understand now, so the question with a FI system compared to a carb system, what caused the bike to not have power.

1.  If the fuel pump always has 40 pis in the fuel rail, that should be good.
2.  Is there more fuel that is pumped through the injectors when you are Wide Open Throttle?  I would guess so, what controls that?
       A.  Throttle sensor
       B.  Mass Air Sensor
       C.  ECU and the ignition box

Is there a way that you can have all these things tested?  I would hope so and that one of the much more qualified people other then me can tell you how  :)

[Laitch]

I would hope so and that one of the much more qualified people other then me can tell you how  :)

You can read all about how the engine systems interact, Timbox, and how to test some of them. Instruction is found in Bert Vogel's troubleshooting flow chart in the Repair Guidance section.

[Timbox]

That is a awesome informational page!   Thanks Laitch for pointing that out...so much info on this forum.

[Laitch]

So I pulled the spark plugs and found them to be wet after attempting to start the bike. So with this discovery would I conclude that I have fuel, and am lacking spark?

Did you ever determine the incoming fuel pressure to the injectors?

[Supershooter]

Laitch
I haven’t ran a fuel pressure test yet, I’ve been dragging my feet because I need to rent a test kit, and I’m skeptical that it’s rhe problem but I’m closer to that step.
Supershooter

[Supershooter]

Martin,
I removed the plugs dried them left the cylinders open for15 minutes, unplugged the fuel pump, hit the starter. The bike seemed to run for a few seconds and ran out of fuel, I plugged the fuel pump back in and it wouldn’t keep running or seem to try, as I unpluggged and re plugged in the fuel pump trying to recreate the little bit of run time, then I messed around until it backfired again and quit. So it might be a temp sensor...? Or did I uncover something else?
Supershooter

[Martin]

As soon as you tried to restart with the pump plugged back in, more likely than not it flooded. Check the plugs, if they are wet most likely culprit is the sensor or sensor connection. Next step is to clean the connection, the step after that is to check the sensor. Getting to the connector and sensor is a pain so it is better to do both at the same time. I use a digital temperature probe and a container of boiling water and measure the resistance at every 5 C degree drop. You need to measure the resistance between the spade connector and the body of the sensor.
Regards Martin.

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K100 Temp Sensor Values.jpg (38.1 kB . 768x464 - viewed 696 times)

[Laitch]

and I’m skeptical that it’s the problem but

Based on what—that nothing has worked so far? That's how it works. :giggles Read this thread all the way to the end.