Poor starting and running after tip over - vacuum carbs?

[mcman56]

I was traveling in an extreme wind area yesterday (Mono Lake) and my Concours literally got blown over in a parking lot.  It could have been on its side for up to 20 minutes.  Petcock was on RES and it smelled like gas when picked up.  It did not want to start .  Finally it would start, idle for a minute or 2 and die.  If I tried to give it throttle it died.  At some point I put the petcock on prime. After 30 minutes or so, it slowly improved so I could ride but it would not take much throttle and occasionally just shut off.  It acted exactly like it was not getting enough fuel.  Slowly it improved so I could go 50 then up to 70 but probably took 20 freeway miles to clear.  This was really odd.  Is it possible for fuel to get in the vacuum system and create issues.  If it ever happens again, is there a quicker way to recover?     

[jettawreck]

Perhaps being on its side and then righted some sediment in the nether regions of the tank got stirred up and deposited themselves into the carbs? Doesn't take much to plug up pilot jets which makes for tough starts and idle. Won't run or take any throttle.

[MAN OF BLUES]

If it is a cali model, and was laying on its right side, yes the vapor canister could have been poluted somewhat... but more likely it is just gack in the tank and floatbowls got stirred up, along with any condensation, and possibly a float or two got wedged up when it slammed the ground...

[mcman56]

It was the right side and is a Cali model.  That may be the cause.  Someone plumbed the vacuum tube to the canister with clear tubing.  It looks almost blocked off by a bend but has been that way for at least 20,000 mile.  At one point during the debug, I did pull it off and it was pulling vacuum.   There was also a point when it was idling on the side stand and when picked up off the stand just died.


I thought about dirt or water but it would seem odd to get to all 4 carbs at the same time.  I have ridden 1000cc 4 cylinder bikes running on 3 cylinders.  I don't remember them being smooth but you could easily ride down the freeway.  I wonder if you could get by on 2 cylinders.  I wonder how much power compressing the 2 dead cylinders would take.     

[jettawreck]

One fuel line feeds all four carbs.
I plugged up all four pilot jets during a tank reinstall while doing a exhaust sprocket install, valve adjust and carb installation. Carbs which had just been to SISF fo the works. Took them back off and cleared the jets and all was well again. Other than my irritation at myself. Flushed the tank prior to the install and figured the inline filter would catch any stragglers. Wrong.

[Two Skies]

I once had a somewhat similar issue when I overfilled my tank (I have Cali emissions stuff on my bike).  That is to say that when the cold fuel warmed up and expanded after a fill up, some fuel worked it's way into the california emissions stuff, and really messed up how the bike was running.  As I remember, I detached the vacuum lines and used my lips/lungs to blow some air through the line, in an attempt to 'clear' the liquid blockage.  This seemed to help, and once the charcoal cannister had a chance to evaporate the fuel/dry out, it was running fine again.  The moral of this story I suppose (if you have Cali emissions) is to not fill your tank all the way to the cap/overflow, especially on hot days.

Some people have removed the Cali emissions stuff (and most Connies don't have this stuff to begin with) as it isn't really needed at all, but if you live in California the State might get upset with you...

So if your bike is running fine now, chalk it up to the emissions hardware getting temporarily gummed up.  Also, the comments about sediments above could  be valid if you are still having issues.  I had a piece of debris partially block one of my float needles once, and by using the 'on/prime' position on my tank petcock while opening the drain screws on each float bowl to quickly flush each bowl, I was able to flush this little bit of blockage away.  Of course, if you have debris in your carbs (I suggest draining into a cup, using a length of hose to attach to the nipples at the bottom of each float bowl as you open it, that way you can see what gets flushed out besides fuel), this might be a good excuse to clean/rebuild your carbs, or even better, ship them to Steve at Shoodaben so he can install some overflow tubes and give you some better/more efficient jets.