Flooding Engine at Low Throttle

[Motofool]

Originally Posted by choneofakind

Nope, at least not that I ever experienced. The only symptoms I got from enlarged slide holes was a funky stutter at 6k during constant throttle.

Thanks, Chone.

Care to diagnose this mysterious case?

[choneofakind]

Nothing is coming to mind right now honestly. I'd just say to make sure the mix screws are at 2.5 turns out. When I had mine 1/4 turn too far out, it made a significant bog when I added throttle slowly. Although, it did start very nicely when cold.

[csmith12]

You have 2 gas jugs in your garage? Your not putting 2cycle in it are you? You adding anything to the gas? Drill the caps off the mix screws and check. The last set of carbs I worked on still had the caps on and they were set totally whack.

[DaBlue1]

Originally Posted by xaple

...My bike is completely stock, no adjustments have been made.

When I start up the bike I get a nice good idle, and when I turn the throttle fairly fast the bike responds well.

If I slowly turn the throttle the engine seems to run super rich and flood. My spark plugs are very black.

I suspect it is flooding because when the choke is on and i slowly give it throttle I get the same result, also when I slowly give it throttle and it starts to bog down the idle drops really low and either stalls or recovers. Once the bike stalls I can not get it to start back up again unless I hold the throttle open max.

What could cause the bike to all of a sudden run so rich that it floods.

I know this has been a long standing problem and I may have missed it, but are you sure your jet sizes are stock 98 mains? And have you tried using any correction factors for your current elevation, temps and humidity. Based on a quick calculation a slightly smaller jet might be a good starting point, to see if you get the same affect. Also another thing to look at is your needle jets. Are they worn?

[tyrone393]

i am new. Thanks for all the info everyone has given. I am not sure if i should start a new thread but this one was close.

i am having somewhat of the problem. i have a 2012 with only 5600 miles (just bought it) so it had been sitting awhile. Same running very rich at idle and i have even found some fuel in the vacuum lines when i pulled them off to check the sync. Main problem right now is that it will run great at times idling at 1500 and then it will idle down to 1000 or a little below and sometimes when coming to a stop after riding strong it will just sometime die.

checked over the carbs and pulled the plugs and are set at 2 turns.

[Motofool]

Originally Posted by tyrone393

i am new. Thanks for all the info everyone has given. I am not sure if i should start a new thread but this one was close........

Welcome to our site, Tyrone !!!

We can only deal with one carburetor's mystery at a time

Bonus info about how our type of carburetors should work:

Link to original page on YouTube.

[DaBlue1]

Originally Posted by tyrone393

i am new. Thanks for all the info everyone has given. I am not sure if i should start a new thread but this one was close.

i am having somewhat of the problem. i have a 2012 with only 5600 miles (just bought it) so it had been sitting awhile. Same running very rich at idle and i have even found some fuel in the vacuum lines when i pulled them off to check the sync. Main problem right now is that it will run great at times idling at 1500 and then it will idle down to 1000 or a little below and sometimes when coming to a stop after riding strong it will just sometime die.

checked over the carbs and pulled the plugs and are set at 2 turns.

Your carbs are set below factory specs. Since you pulled the plugs out you might as well set both carbs idle mixture at 2.5 turns out and go from there.

[tyrone393]

thanks will set them to that. And thanks for the video!

[alex.s]

idea: sell carbs on ebay for 50$ "as is", then buy a new set? :P

[xaple]

Originally Posted by DaBlue1

I know this has been a long standing problem and I may have missed it, but are you sure your jet sizes are stock 98 mains? And have you tried using any correction factors for your current elevation, temps and humidity. Based on a quick calculation a slightly smaller jet might be a good starting point, to see if you get the same affect. Also another thing to look at is your needle jets. Are they worn?

I used to run 98 dynojets when i ahd the exhaust on, now that im back to stock i put in the stock 96's
Put back in stock needles too.

[xaple]

Originally Posted by alex.s

idea: sell carbs on ebay for 50$ "as is", then buy a new set? :P

Considering this since school is starting soon and I will need a vehicle within the next month.

[xaple]

I think I figured it out. It is either the bowls or the float valve.

Due to my super high tech experiment using a funnel and clear tube I set up a controlled gas tank. I put gas in the funnel and let the bike run on idle with the adjustment knob turned all the way up.

By turning this up this far the bike was in a constant state of "bogged down" at 1k RPM ,as if I was opening the throttle slightly. Which is what the knob basically does. Once the fuel started to run out in the bowls the idle shot up to 5k, which is how it normally should.

Once that happened I knew the fuel level had to be where it should be. I tested by changing the idle back to normal and then slightly opening the throttle on my own to see if I still had the same symptoms. The bike ran like new. No hiccups at all.

This is pretty pinpoint that the fuel level is not correct and I have adjusted the float height and it did not work. So I ordered 2 new float valves, and will also check to make sure the floats actually... float when i take the carbs off again.

Thanks everyone for the input, this took a ton of time but honestly worth it. I have learned so much and saved some money. Hopefully this is it!

[csmith12]

After all the trail and error, I would feel like this



But glad progress is being made!