So 2 days ago I found myself stuck riding my k100 in the rain. I was in decently heavy downpour for about 45 min or so. As I'm nearing the home stretch of the journey see chokes out. I drop her to 2nd, pop the clutch and back to the grind again.

Then she chokes out again. Luckily I was beside a gas station so I pull in. I check to see if she's low (cafe conversion, I replaced speedo so no wearing fuel light) and I've got 1/2 a tank.

I try her she fires but struggles. I make the last mile to the destination and get the ornery girl under a cover to wait out the rain while I see some friends. I come out a few hours later and she won't turn over. Single fire, then off. I hear the fuel pump whines but she won't official fire. 

I left her for a day at my friends and let the sun dry her a bit. This is where I'm at. Help!

https://s22.photobucket.com/user/mikeisdead/media/k100/F6D24258-2225-479C-A51C-EDB6AB2C97C6.mp4.html

That wasn't much info to make a diagnose out of.....
Start with pulling the spark plugs and check how they look, wet, dry, colour.

Could be the battery. Worth testing even if just to eliminate.
A voltage reading under load will tell.

Check for water in the fuel, a light (not match) shine into tank and if there is water it will be in the bottom of the tank.
If there is water drain refill and put some alcohol in there to take the water through the system. Water will get into the injectors so wind it over to make that pass through.
Water in the electronics, the ECU is supposed to be sealed but 25 years on it usually isn't. Remove it and check inside for condensation, don't touch but put it in the sun to dry out and DON'T microwave it they explode the chips sometimes.
It may not be water but chances are that it is.

I wonder how much rain got in through the snorkel to the air box.  Forward facing with no baffle, heavy rain...

I'd pop that first to see what's in the air box.

Second, I would see if there is any water under the cover for the hall effect sensors on the front of the engine.  I don't know how water proof their functioning is, but given their location I would be concerned about how dry they are.

Two easy checks with(to me) high probability.

CA model has the fuel vapour emissions system for CA only.

Is there a risk of water getting into the gas tank via this route if it was altered?

There is also a drain at the fuel cap, in the recess, if this was altered or damaged it could go wrong.

Since it is a café conversion the normal fairing protection for the ICE against rain is absent. The switch connector blocks under the gas tank are also more vulnerable. Absence of front mudguard/fender also increases risk. Over here we get lots of rain and removing these things would be risky.

If its turning over and the fuel pump is running, will it fire at that point if you keep the starter button pressed?

Point-Seven-five wrote:I wonder how much rain got in through the snorkel to the air box.  Forward facing with no baffle, heavy rain...

I'd pop that first to see what's in the air box.

Second, I would see if there is any water under the cover for the hall effect sensors on the front of the engine.  I don't know how water proof their functioning is, but being where they are I would be concerned about how dry they are.

Two easy checks with(to me) high probability.

Definitely. No front fender really exposes these in the rain.

Thanks gentleman for the fast reply. I will got to her today and start attempting to find her prob through these suggestions.

I'm truly grateful for you taking the time to help. Cheers
-mike

Keep us posted on what you find.

So far...

-tested the battery, good to go. 
-pulled the spark plugs, (changed a year ago) they looked okay. I cleaned them up and tested each for spark. Good to go
-pulled the fuel injectors, and they were shocking dirty. (I had them cleaned and tested about a year ago) I got the gunk off them and returned them 

In the even that gunk was built up inside the block where the injectors insert, is there an easy way to clean in there?

With the injectors back in place, I tried to crank her again. Same as in the video. Next I -

-pulled the tank and removed all possibly watery gas. I'll get back to the shop tomorrow and see if fresh gas was the gremlin. 

What is the Procedure for adding alcohol to remove the water? Or will the removal gas from the tank cover that?

I use methylated spirit to get rid of the water. About 150ml to a tank will absorb the water and stay suspended in the fuel or if you use ethanol fuel E10 that will do the job.
To clean the gunk from around the injectors I use a vacuum cleaner and a long stiff bristle brush It's a PITA that we have to live with.

MikeisonTV wrote:.....
-pulled the fuel injectors, and they were shocking dirty. (I had them cleaned and tested about a year ago) I got the gunk off them and returned them 

In the even that gunk was built up inside the block where the injectors insert, is there an easy way to clean in there?
.....

No real way of cleaning that out apart from taking the head off. When everything is sorted it should burn away anyway. If it's as bad as you say, I'm betting you have a problem with fuel ignition which could be separate to your running problems. Sounds like you are getting too much fuel even if your plugs look ok. Leaking injector/s probably the cause.

IF you do have water in the tank and it's been there for a while, this may be the cause of leaking injectors even tho you had them cleaned a year ago. They don't like water and will quickly corrode causing rust particles to lodge in the pintle valve preventing it from closing completely.
"Getting the gunk off them" won't do anything.

Questions:
What does the exhaust look like? Thin grey/black soot or thick sooty (possibly oily) deposit... maybe even smelly??
Was there any water in the fuel when you emptied the tank?

Questions:
What does the exhaust look like? Thin grey/black soot or thick sooty (possibly oily) deposit... maybe even smelly??
Was there any water in the fuel when you emptied the tank?sswapped out The gas?

So I got a chance to wrench on the girl today.

I already had checked the air filter (K&N) and it seemed ok.

Swapped out all the fuel and dumped the excess from the lines and fuel rail. 

Brought my backup battery and swapped.

Still much of the same...it fires but won't continue to run even with the button down.

At 1st was some light black smoke (my k isn't generally a smoker) and a smell....but she won't actually run, thoughts?

I would say that now is a good time to head for the portal and download Bert's troubleshooting guide and work through it step by step. I think that fuel over supply is the main problem.

Ok Rick...I'll give it a go

Turns out there was some tank crud build up under the fuel pump...she's very alive and running well now. Thank u guys for all the ideas and support in diagnosing her!

Thanks to you for letting us know what you found. 

Crud in the tank, how does the rubber vibration mount for the fuel pump look?  Is it starting to fall apart?

I agree. The rubber damper ring turns to mush and if the nylon screen is damaged, the pump can pick up the particles and seize. They can clog up the in line fuel filter, too.
General opinion is that it's the additives in modern fuel that does the damage.

Comberjohn wrote:General opinion is that it's the additives in modern fuel that does the damage.

Yes John, but it only seems to happen if the bike is left standing.

So to prevent it happening, 'KEEP RIDING' 

Paul.

Of course I got caught in rain again as I was out a few weeks ago. 

She performed fine during the downpour. I turned her off when I reached my destination. When I returned to leave, back to the same failure to turn over problem from last time.

Towed her home, and didn't feel like messing with her for a week or so.

There's a fun twist this time. 

When I hold the starter button down, she will fire then off, repeatedly, over and over. 

Then she kinda ran for 7-10 seconds before-

A nice cloud of white smoke and a flame out the pipes. Her last gargle of life. 

Now it seems that fuel is leaking from where the weld of where the header pipes join the muffler under the bike. (I checked all the lines and around the rail and no leakage there. 

It looks a little oily, and I get a single drop every 15-20 seconds. As unfortunate as this is, maybe will help us know what her problem is...?

Fuel filter! Two times I had a problem with filter fuel filter, both on the long trip when engine needs constant fuel supply and pressure. If it is partly clogged it will stop.

Unburnt fuel ejected out the exhaust valves and into the headers from cranking and no start. Once you get it sorted you'll need to change your oil as fuel also finds its way into the sump.

Water could be the problem then??
Maybe water in the fuel from a leaky fuel cap gasket. That would probably give you the white smoke. Did it dissipate quickly? If so it was probably steam.

Also, your bike is naked so there's a possibility that rain could be making its way into the electrical area under the tank behind the steering head where the ICU is. There are 2 plastic covers which go between the head/frame/tank right at the front. Could be they're missing because they normally screw onto the fairing bracket. So they were probably ditched when the fairing was removed. Rain could be getting in there and affecting the ICU/ignition???

What are your plugs like?

Kaptain Holister wrote:Unburnt fuel ejected out the exhaust valves and into the headers from cranking and no start. Once you get it sorted you'll need to change your oil as fuel also finds its way into the sump.

Water could be the problem then??
Maybe water in the fuel from a leaky fuel cap gasket. That would probably give you the white smoke. Did it dissipate quickly? If so it was probably steam.

Also, your bike is naked so there's a possibility that rain could be making its way into the electrical area under the tank behind the steering head where the ICU is. There are 2 plastic covers which go between the head/frame/tank right at the front. Could be they're missing because they normally screw onto the fairing bracket. So they were probably ditched when the fairing was removed. Rain could be getting in there and affecting the ICU/ignition???

What are your plugs like?

I removed the fuel filter and can blow air through it with no obstruction. The fuel pump whining as it normally does (although we know to never rule these out.

I'll pull the plugs today and report. Good to know the fuel issue isn't a huge thing. I was worried. 

The smoke did disputed quickly YES. I'll remove the gas in case in was water too if you guys agree that's highly likely.


Can one of you guys snap a shot of the plastic covers that you speak of?

These sit under the tank and cable tie on in a couple of places. There are lugs at the front where they screwed onto the fairing bracket. There's also a rubber gromet which seals around the steering lock.
You can pick up a set of trim from here which includes the plastic covers pretty cheap.

Thanks for the pic update! Those are definitely MIA on this CAFE. What would be the likely disturbance under the tank if water snuck under the tank? If the ignition box is out, would the bike try and start?

Thanks again for some direction and advice here...

Have you taken the plug out from the ICU I have seen water in the water proof rubber cover.

Water shorting out the ICU plug could certainly cause problems with ignition. Result could be a range of symptoms... hard to be specific but start issues for sure.

I'd be checking for water in the tank first tho. Give it a swish around and empty the fuel into a clean bucket and take a look. I was surprised what I found in mine when I first bought her. If there's water, rinse the tank with metho and put the fuel back in. You might need a fuel cap gasket kit.

I'll pull that ignition ECU plug from under the tank and see. I'll also spray it with DeOxit before rejoining it.

Remove the gas from the tank, flush the rail, and flush the lines. I'll also check the plugs and report my findings back.

It was bad gas...swap it for fresh and she's fired up. Thank you guys all for the help!!! Damn I love riding this bike 😍😍😍