Start and Idle Issue

[lboaman]

Hey Folks!  Another newb looking for assistance for what is likely another carb issue!

So backstory ->  Bike had a hanging idle issue and a stuck choke cable.  Replace the choke cable and took out the carbs for my first shot at cleaning them, and hopefully finding something alleviate the hanging idle.  Carbs were cleaned, new stock needles & valve seats installed, new air filter, replaced several o-rings.  Put back together, and set my float heights; were high, they look good now.  Air/fuel screws are 2 turns out.

Now I'm having what looks to be a nasty rich fuel mixture or overflow.  I can start the bike, but only with full choke and giving a bit of throttle.  It will sit at 1-2K rpms for a couple seconds, then jump to 5-7K rpms.  After about 30 seconds or so, it will bog down and stall out.  Half the time fuel will start flowing out of the air box drain hose.

What would cause this overflow if my floats are the correct height?  It seems like its just running really rich, which is causing the trouble starting and eventually causing the bike to stall out. However, this is coming from the guy who is doing tons of guessing/checking and not getting too far...

Appreciate the help folks, any and all ideas would be greatly appreciated!  Feel like I'm one step away from getting this thing purring!

-lboaman

[kylegod]

perhaps your floats are sticking open? but i dont think that would make fuel in the airbox... are you running stock filter and pipe? jets? also, that jumping to 5-7k could be a vacuum leak.

[lboaman]

Thanks for the reply, kylegod.

I don't think the floats are sticking open, otherwise the float height tube check would be way off.  Everything is stock: filter, pipe, and jets.  I sprayed WD40 on the boots to the cylinder head and air filter, but never got a change in engine speed...

[JAY W]

sounds like float height,carbs flooding.Have you tried using a clear pipe on the drain outlet running the tube up the side of the carb,opening the drain screw it should level to just under the bowl gasket,if not you will need to readjust float height.Combo Jay

[centuryghost]

Maybe when you installed the new needles the washers were placed in the wrong spot making it super rich? I would pull the carbs and double check everything.

[lboaman]

sounds like float height,carbs flooding.Have you tried using a clear pipe on the drain outlet running the tube up the side of the carb,opening the drain screw it should level to just under the bowl gasket,if not you will need to readjust float height.Combo Jay

I was having this issue earlier, but solved it.  One of the new valve seats i bought was not seating correctly and the fuel would constantly seep through, overflowing the carb.  Took the new o-ring off of the new valve seat and put the old valve seat back in with the new oring.  Tube method of showing the float heights has them dead on now. 

Maybe when you installed the new needles the washers were placed in the wrong spot making it super rich? I would pull the carbs and double check everything.

Maybe... I placed the needle back in as how I believe it came out.  Never took the, what looks to me like the washer, and little plastic orange piece off of the needle.  I can pop the tops and post a picture of how I have these inserted and what they look like tomorrow.

I've double checked everything best I can... Had the float bowls off several times adjusting the float heights, and took the tops off the carbs to make sure that tiny o-ring was still sitting there (not sure what that spot is used for, vacuum something?).

Also, I've did the quick mod on the frame petcock that spins the selector 180 degrees to avoid the vacuum operation.  However, I haven't capped off the hole on the left carb that runs to the petcock.  I still have that hose connected at both ends.   Don't think this would affect anything?   

Thanks for the reply guys!  I'll keep checking if yall keep coming up with suggestions!

-lboaman

[lboaman]

Here is my needle...


and how it is inserted in the valve.


Anything wrong?

Also,  I'm not having the overflow and leak out of the airbox drain hose anymore.  I believe this was either caused by my earlier float height issue, or by giving the bike too much throttle when trying to start it, thus flooding it.

Now the bike fires right up with no choke and jumps right to 7K rpms.  I hear kind of a 'gurgling' noise from the exhuast, and am getting a backfire when I cut it off.  I have the air/fuel screws at 1.5 turns out now.

If it wasn't for the fact that the bike starts right up with no choke, I would say it was lean and I have a vacuum leak of some kind.  I don't think this is the case though, this sounds like rich right?  Throttle cable doesn't look stuck.  I've also tried running the bike with no air filter in it for about 20-30 seconds; didn't get any different behavior.  What other factors could cause it to run so rich other than float heights, air/fuel screws?

Thanks guys!

[kylegod]

If it jumps to 7K, it sounds like vacuum, but you said you checked.

So if its just revving and hanging or slowly coming down, means its super lean. Dunno why it would be so lean though with no mods. So turn out two turns to start and go from there. also let it warm and check your idle screw. also synch carbs.

[jeremy_nash]

turn the idle screw way out, then try starting it again.  you may have adjusted it way too far in when you were trying to get it going, and forgot to adjust it back out

[lboaman]

perhaps i've been thinking about it wrong then.  Since the bike is able to start without any choke, I was thinking that it was running rich  .  However the hanging idle seems like a lean issue; which forms a contradicting issue...  I've been adjusting the air/fuel screws to lean it out; perhaps i need to try and increase the fuel mixture.

Idle screw is just a couple turns in after hitting the throttle.  Throttle snaps back with no sticking.  I haven't tried synching the carbs yet though.  I'm in the middle of tearing the carbs all with way down and double/triple/quadruple checking everything (though probably don't know what I'm looking at!)  Syncing the carbs and adjusting the mixture screws out rather than in will be my next steps.

Thanks!