My KLR won't run

[Osnabrock]

My KLR has gotten very little use over the last two years.  I've probably only ridden it about a hundred miles each of those years.
Today I got the urge and it wouldn't run without the choke engaged so I took the carb apart to clean it and this is what I found..........

[Lonesome Dave]

I love ethanol.  It makes everything run so good!    This summer I started using "Star Tron" and "Sea Foam" with every fill.  I'm sure you've heard of SeaFoam, but Star Tron reverses the effects of ethanol with an enzyme.  Basically, it breaks the moisture down that ethanol naturally attracts, into microscopic droplets so they will be burned or passed though.

Over the years, I've wasted so much time taking apart carburetors on different things, i.e., chainsaw, trimmer, pumps, bikes, you name it.  So this year, I numbered my gas cans and when I fill them, I treat them.  (At least so far!) 

[Osnabrock]

I had fuel stabilizer in the tank, or sea foam I don't remember which I used.  Oh well, I should have been more prudent about getting the gas out of the float bowl.
Cleaning the carb had little effect on the performance of the bike only now I can get myself around the block but it's still running poorly.  I didn't try to ride around the block before because I knew something wasn't right.  In my mind, I still haven't fixed anything.
I did change the air filter without real improvement.
I'm getting spark, I'm getting air, I guess the problem is fuel.  Maybe it's a problem with the mixture screw or the pilot jet? 
Any suggestions?

[Dr Psyko]

I don't know much about the KLR carb, but knew racing carbs well back in the day. Floats are finicky creatures, and the valve that allows fuel into the bowl can become mysterious with age, best to replace and recalibrate for height. Also, check and blow pressured air through the various air channels in the carb. Can become clogged, and not visible when cleaning. I'm cringing as I write this because I face the same job on my ducati and the klx, neither have run this this summer.

Cheers!

[Hank]

Start with the simple stuff, like changing the fuel in the tank.   Modern fuel can go skanky in short order.

Double check the pilot circuit in the carb.

If it still runs crappy with new fuel and a clean carb, check for vacuum leaks.  Maybe your intake boot developed a crack, or the petcock vacuum line split.  Also possible the vacuum diaphragm in the petcock is leaking and dumping excess fuel in through the vacuum line.   I've actually had all three of those things happen in the last 18 months.

If it runs better with the choke on, its not the vacuum diaphragm though.

[Osnabrock]

I thought I did a pretty good job of cleaning the carb.  I soaked things for as long as I cared to and blasted everything with compressed air like you suggested Psycho.  It's hard to tell exactly what passages the air is actually traveling so I'm not 100% confident that I won't end up pulling it out again.
I'll get another float valve on order as you suggested.
I'll check the petcock next to see if it might be the problem. Thanks Hank.
There's also what they call the "air cutoff assembly" on the side of the carb.  It has a diaphragm that might be the culprit too.  The rubber on the diaphragm seemed a bit stiff when I removed it.  I guess I'll put one of those on order too and see if it does any good.  Luckily, I think I can get to that part without removing the carb from the bike.
I'm bummed that it's not running as it should.  I was really excited to ride it.

[Hank]

When its idling spray a little carb cleaner around the manifold and petcock vacuum line.  If the idle picks up you'll know you have a vacuum leak.

A float and float needle might be in order, but issues there will normally manifest themselves as rich running or, more likely, the pissing of gas all over everything.

I don't think the ACV (air cut off valve) would make it run crappy either.  That should only be active (I think) at closed throttle during decel.  I think it's function is to cut off air to prevent an over lean condition and the associated popping on decel.

[Hank]

Re-reading your earlier post it sounds like maybe you didn't remove the pilot jet?    If that's the case I'd be pretty confident the problem lies there.   With a plugged pilot the bike usually won't idle worth a damn unless the choke is on, but it will run OK above say 2500 or 3K RPM.  The pilot jet is really small and really prone to plugging. 

[Dr Psyko]

Agreed with the pilot jet. When we were racing, a common tech check for cheating was to spray ether around the motor. Our intakes were metered, and restricted. If the idle ran up when ether was sprayed, a cheater had found a way to get more air into the engine.

[Osnabrock]

Now here's the quandary.......
I think I took out all the jets but I don't specifically remember taking the pilot jet out.  Sadly, the only progress photos that I took don't show that I removed that jet. 
Psycho and Hank, your logic is sound.
I have learned enough in my time that I could mess around with any number of things and not find the cause.  It's only a half hour job to remove the tank and carb on the KLR so that's what I'll do
I'm going back in.  It won't be 'til next week, but I'll keep everyone informed.
Thanks for the input.
Sincerely.

[Osnabrock]

I pissed around with the carb a few times this week.  The way the carb works isn't too mysterious to me so I felt that it had to be a simple problem.
What it boiled down to was just cleaning and recleaning the carb.  The final time, after which the bike ran, I cranked the pressure on my compressor as high as it would go and, again, blew out all the passageways I could find.  I still don't know exactly what the problem was but I have a feeling it was the pilot circuit.
Sadly, there's no real moral to this story other than knowing that sometimes it's inevitable that things have to come apart repeatedly before the solution arrives. 
Thanks for the help everyone.

[Hank]

Good work!

Sent from my Pocket Altair 8800