Troubles Continue - won't start after 2 days parked (stuck valves?)

[Dave_A2]

So I fixed my fuel tank and fuel pump issue (And the associated leaks from the lower tank), and got the bike running on the center-stand...
Filled with fresh regular ethanol-free unleaded (I have a 500gal tank that's normally used to fill up an airplane)...
Ran it up to operating temperature once or twice after that... Everything appeared to be fixed...
Then took it off the center stand & rode it slowly (feet down) about 100ft from my shop over to the house....

2 days later, when I came out in the morning to ride to work... Would crank, wouldn't start.

After a new battery, still won't start. Will backfire occasionally while trying to start if you crack the throttle while cranking.

At this point I took the airbox cover off & tried to run it on starting fluid. No joy.
The previous non-start condition (Fuel pump/tank debris related) DID run on starting fluid. So this isn't the fuel pump again.

Taking one of the snorkels off I can visibly see a strong fuel-spray from the injectors.

I then took out and cleaned all 4 spark plugs.
Noticing that the plugs were sparking to the edge of the threads not the tip (when grounded to the frame so I could observe the spark), I narrowed the gap on all of them until they spark from center-electrode to tip. These are new plugs put in during the fuel-pump repair episode, along with an oil change.

The bike still will not run.

I am thinking stuck valves (on all 4 cyls, all at once?) but don't have a compression tester that will fit (off to Harbor Freight).... Also the 'airplane' compression tester I do have requires setting the cyl to TDC before testing....

Any advice? Any way to free up stuck valves on a bike that won't run, without tearing down the engine?

 

[Mellow]

I'll start with the obvious, kill switch on?

 

[SMSW]

Doctors have a saying, when you hear hoofbeats, don't think of zebras (ok, @Erdoc48, I may have mangled that a tad). That means, you go for the obvious. @Dave_A2, why do you think its stuck valves? On all 4 cylinders at once? You said the bike ran ok after your fix, though it sounds like your spark plug replacement might not have been done properly. Did you gap the plugs to spec or just "narrowed the gap on all of them until they spark from center-electrode to tip". There are reasons for specificatons, and trouble shooting that follows a logical progression. I'd start by going over the work you just did and make sure it was done 'by the book'.

 

[W0QNX]

This is what happens when you ride with your feet down.
v
v
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But did you try the flooded ST routine? hold the throttle wide open for longer then you think you need to. 15 seconds?

Sounds flooded to me.

Definitely not stuck valves.

 

[ToddC]

Dirty kill switch.....?

 

[Dave_A2]

Doctors have a saying, when you hear hoofbeats, don't think of zebras (ok, @Erdoc48, I may have mangled that a tad). That means, you go for the obvious. @Dave_A2, why do you think its stuck valves? On all 4 cylinders at once? You said the bike ran ok after your fix, though it sounds like your spark plug replacement might not have been done properly. Did you gap the plugs to spec or just "narrowed the gap on all of them until they spark from center-electrode to tip". There are reasons for specificatons, and trouble shooting that follows a logical progression. I'd start by going over the work you just did and make sure it was done 'by the book'.

The spark plug thing was AFTER the initial failure & well into trying to figure out what the hell was wrong that it wouldn't even run on starting-fluid....

I'm going to try another set of new plugs (with no gap changes).... And I'm still also going to find out what my compressions are once I get a usable tester.

 

[Dave_A2]

This is what happens when you ride with your feet down.
v
v
v
v
v
v
v
But did you try the flooded ST routine? hold the throttle wide open for longer then you think you need to. 15 seconds?

Sounds flooded to me.

Definitely not stuck valves.

Tried that several times before I took it back apart.

At most you get one explosion out the exhaust... It doesn't even try to run.

 

[Dave_A2]

Dirty kill switch.....?

Kill switch works as expected, pump runs, FI light goes out...

 

[Dave_A2]

I'll start with the obvious, kill switch on?

Kill switch on, plugs fire, engine cranks, fuel sprays.

 

[wjbertrand]

Hard starting is not typically an ST problem. I’ve never heard of an ST having stuck valves. I think that’s a bit of leap conclusion wise. Are you 100% sure you have the correct spark plugs in there?

 

[Al st1100]

if its flooded, disable fuel pump, crack throttle open while cranking. there may be a plugged 5 way tee or something causing it to dump too much gas on start.

 

[SMSW]

The spark plug thing was AFTER the initial failure & well into trying to figure out what the hell was wrong that it wouldn't even run on starting-fluid....

I'm going to try another set of new plugs (with no gap changes).... And I'm still also going to find out what my compressions are once I get a usable tester.

I was taught by an old mechanic to always gap new plugs to spec. Any given spark plug may be used in many engines with different ignition systems.

 

[diferg]

disconnect fuel hose and pump some fuel through fuel pump into clear glass container, inspect fuel for water from residual condensation. from bikes tank. (you probably check 500 gal tank before each use)

 

[woodybelle]

If the valves are stuck open, which has been known to happen to other STs, mine included, it will crank over without much resistance. You will be able to hear the difference from a normal engine if that makes any sense. It will indeed flood if the fuel is going in and it is not igniting. I would crank it a bit to get some fuel in the engine and then hold it wide open to stop the fuel flow and crank it until it fires up. It may start running on 1 cylinder initially but after that it should free up the other valves. A previous discussion on this issue blamed the gas, causing gummed up valve guides. I hope this helps.

 

[Bmacleod]

If there was debris in the tank, it's possible some may have gotten into the fuel system and could be causing an injector or 2 to stick, causing it to flood, which it sounds like it may have flooded. I would go ahead and remove all the snorkels and then turn the key on and look at the injectors and see if there's anything leaking. If you see any injector(s) leaking, there's your problem. And I would get some new plugs and set the gap to the proper setting and leave it. The likely reason the spark was jumping to the side is because the plugs were likely wet and the spark was following the path of least resistance

 

[wjbertrand]

How does one confirm stuck valves without disassembling the engine?

 

[SMSW]

How does one confirm stuck valves without disassembling the engine?

Compression test. Also a leakdown test. If you have a fiber optic bore scope that might work too (in through the spark plug hole. A valve cannot be stuck closed, the cam will whack it open if that's the case. I would think were a valve stuck any more than a little bit (open) it would be battered by the piston and then you have either 300+ lbs of scrap aluminum or an expensive repair.

 

[Grabcon]

If you have done all the things suggested in your thread, pull the valve covers and check your valve clearance. I had this happen on a ST1100, my valve clearance was very tight and the bike would not start. went thru and reset the valves and everything work great.

It has been some time but if I remember correctly before it wouldn't start I had poor mpg, deceleration popping, and hard starting until it wouldn't. Then it would crank and pop but no start.

 

[Ryan_B]

If you are getting fuel and spark it has to be air (assuming you have compression). Did you forget a rag stuffed in the intake? Can you feel air exiting the exhaust? I can't tell you how many hours I worked on an older vehicle, timing and re-timing that darn thing and all I would get was a feeble backfire. This was after I had rebuilt the engine, so I assumed it had to be something I had done. After several months of checking and double checking off and on I towed it to an old retired mechanic. Took him about an hour to figure out that mud dabbers had built a nest and completely plugged the exhaust.

Ryan

 

[Grabcon]

@Dave_A2

What is the verdict? Did you get it running?