Carb cleanout

[ThatOtherGuy]

So I balanced the carbs a few weeks back and since then I think a bit of gunk slipped through the fuel line into the carbs blocking something and generally causing some issues.

Diagnosis so far.  Overflow from air box will leak raw fuel and lots of it, I have checked inside the air box which is standard.  Turn petcock grub screw to off and it stops, turn it on it starts overflowing, but not all the time and sometimes it doesn't even do it (leak fuel).  Bike runs rough under 4k, then picks up fine, idle is a problem most of the time, occasionally its fine.

I have eliminated any other issue such as spark, plugs, electrical, charging etc etc.

Being a leave well enough alone and a "if it ain't broke don't fix it" kind of person, I am not keen of a full carb rebuild if it is not necessary, I see no point in creating an issue where it does not exist, though it does not scare me or is beyond me to do that.  If it is a simple drain and clean issue, which is what I think it is, then that is all I will do, at least to begin with. 

Thoughts!

[jestercinti]

Float height?   Weak or worn float needle seats? 

[ThatOtherGuy]

I'm guessing it has something to do with either of those.  I did scour the forums for a few hours last night trying to find an answer.  I am leaning toward something dirty though since it only happened straight after the balance and that is the only time a foreign material could have been introduced.  The problem never existed prior to the balance and is intermittent after the balance.  I'm leaning towards floats stuck based on what I've read so far, so figuring a drain and clean out is my first course of action.  As I mentioned trying to reduce additional issues I could introduce, I like to be methodical in my approach and tick of the obvious before trying to find the obscure.

[dread_au]

i will be interested how you go as mine is doing similar things to yours. What model is yours?

[salamander]

Float height?   Weak or worn float needle seats? 

If not these, try giving the passages a quick squirt of carb cleaner.  Probably means taking the carbs apart farther than you wanted, though.

[ThatOtherGuy]

i will be interested how you go as mine is doing similar things to yours. What model is yours?

2005, been very good up until the balance and hence my reason for not wanting to mess with it unless I really have to.

[ThatOtherGuy]

Float height?   Weak or worn float needle seats? 

If not these, try giving the passages a quick squirt of carb cleaner.  Probably means taking the carbs apart farther than you wanted, though.

yeah going to stop by the auto store on the way home and pick up a few things like carb cleaner etc.  really want to avoid a dismantle for two reasons.  not introducing a new point of failure and most importantly I'm riding my wife's bike as a commuter and both of us don't like that.   she because I am riding her bike (she's quite adamant about that), me because its a cruiser and it hurts my back.

[ThatOtherGuy]

May have got a break using the carb cleaner.  Set up the tank, picture below, started up the bike after giving the carbs a spray with cleaner and leaving to dissolve the accumulated gunk.  Ran the engine for a bit warming it up, then sprayed in carb cleaner in intervals into each carb whilst revving it.  Let sit idle and off for a time, restarted engine, rinse and repeat, did this about 3 times.  Engine now idles steady without issue, also does not seem to leak fuel into the air box, so I am thinking it was just a glitch in the carbs, hopefully the problem is solved.  However I will be monitoring it and not using the bike for a week or so while I do other maintenance that is due.

However I do have another query, in the second photo below you can see a tube that I have for now folded and cable tied.  For the life of me I cannot determine if it should attach to anything and I cannot remember ever detaching it at any time.  The end is flared suggesting it did attach to something.  The other goes to the carb manifold and if I gently blow in it, fuel leaks into the air box, sucking and I get vapour and probably a mouthful of fuel.  The only tubes I disconnected were the two fuel lines and the tank filler drain line.  Any help identifying its use would be appreciated.

Ghetto fuel sling using my bicycle work stand and a piece of rope:


Random tube I would like to identify:

[snOhio]

is that the float bowl vent tube?  connected to a tee that runs to the carbs?  if that's the case, snip the zip tie and let that puppy breathe.

[ThatOtherGuy]

you're probably right, will do that when I put it all back together.  when running , open or closed it made no difference, no vacuum or pressure.  it just looks weird because the end is flared like it should be connected to something.

[jestercinti]

Carb vent tube.  DO NOT have any kinks.  Your bike will not run right.  Search for "Crosswind Engine Stumble"

Found this out the hard way.

EDIT:  Route the hose on op of the airbox and have the end between the airbox and battery.  That's how it's supposed to go.  Do not have any kinks.

[Calpantera]

Carb vent tube.  Route the hose on op of the airbox and have the end between the airbox and battery.  That's how it's supposed to go.  Do not have any kinks.

Not to hijack but that is a great piece of info there Jester, mine ran down to the bottom of the frame.... Thanks!

[bombsquad83]

Carb vent tube.  Route the hose on op of the airbox and have the end between the airbox and battery.  That's how it's supposed to go.  Do not have any kinks.

Not to hijack but that is a great piece of info there Jester, mine ran down to the bottom of the frame.... Thanks!

The point is to keep the vent out of the wind, lest you experience the "cross-wind stumble" that has been discussed here before.

[ThatOtherGuy]

yes aware of the cross wind stumble, thought that was another vent tube elsewhere.   dammit, just when you think you're starting to understand your bike, you learn a little more.

thanks guys, consider the zip tie gone.

[ThatOtherGuy]

so after a few days of sitting in the garage, no leaking fuel now.  typically just prior to this issue, there would be a constant smell of fuel and occasionally a pool under the vent tube.  looks like a basic carb clean has solved the problem.  thanks for all the assistance, suggestions and ideas.

[jestercinti]

No problem.  That is what we are here for.

[kbankovi]

I too wanted to know what that other tube was used for.  I was putting my bike away for winter  last weekend and noticed that tube wasn't connected to anything.  If I stuck my hand against it the bike would almost stall.  I put it all back together thinking I would deal with it when I get it back out. Luckily this solved my issue.  Thanks! 

[crzydood17]

If you have a K&N and a late model (04 and above) the best place I found for it was under the K&N sorta between the carbs, I had it route to below the bike, and got a stumble, couldn't get it up to the battery then i moved it around though the bracket for the vacuum switch and it works great!