Mostly I'm just venting, but please send happy carb thoughts my way

I was close to pushing Scarlet over a cliff at 6:30 this morning. She's essentially a good daily driver, and frequently I ride her to work, which is what my plans were today.

But every third or fourth morning I decide to ride, carb #3 starts puking fuel when I turn on the fuel valve. Once I jumped up and down on the foot pegs, and jerked the bike from side to side, the float valve seated and the engine started fine. But when I turned off the choke, the engine started racing, wouldn't return to idle, and I had to shut it off and eventually just wheeled it in the garage. A new, random problem. SO IRRITATING at that time of morning, with the expectation of a nice ride.

Especially irritating because I've had the carbs apart forty-eleven times over the last 20 years of ownership, and went over them again -- and again -- thoroughly last year, to try and finally exorcize these types of demons. And with all the help and education I've received on this forum for nearly two decades, I feel like I'm no slouch in what to look for and how to adjust them.

I guess I'll be adding yet another carboscopy to my already long to-do list.

 

Hello , you stated you had carbs tore down , it sounds like your float needle is hanging up , if you pull float bowl check the tip of the needle if it has a groove ot tip is stiff replace it . You can also use a Q tip with some metal polish chucked in a drill a couple of pulls of the trigger will polish it up. Also check float height 17mm measured from the fwd flange to bottom side of the float .

 

I feel your pain as do many others that are on this site, my bike is running good now but it wasn't easy for me ether.
As for your issue I agree with Jetfixer,and are you getting the best parts possible for the needle and seats for your float bowels. Wet set is also critical adjustment for the floats as I'm sure you have read a few time's.

My next bike will be fuel injected LOL

 

Then you get to dral with even more electrical/electronics! Obviously not that big an issue if you are able to work with electrical/electronic systems, lol

 

When I got back into it a few years ago I vowed that I would only go EFI because I didn’t want to deal with carbs. So far that plan is not going well.

 

Hahaha, yes, my dream is of fuel injection, too, but I've never really been afraid of carbs. They don't usually give me too much grief that I can't deal with it.

To Jetfixer and JCH, the most recent carb teardown/rebuild was in 2018/2019, using a carb rebuild kit from Len/XJ4Ever (as always). I've had the intermittent needle no-seat/flooding issue the whole 20+ years I've owned the bike, so I'd guess it's not a needle quality issue... but may be a seat issue or a float-hang issue (i.e., catching on a too-large gasket, increased slop in the float-pin assembly, etc., etc., blah-blah-blah). I'll definitely dig into those areas with a fine-tooth comb.

Now for the update on the new problem, the sudden racing idle at startup.

This morning was a great morning to ride to work. I had let the bike set for several days because of my irritation, and walked into the garage this morning with a clearer head and more patience.

I stepped back, and asked myself what had changed since the last time I rode it two weeks ago, when there was no racing idle. Aha! I had tinkered a bit, and had unbolted and moved the handlebar assembly out of the way to re-torque the steering head bearings... so I had to have disturbed the throttle cable by moving the handlebars.

Sure enough, the end of the throttle cable was pulled slightly out of the handlebar hole, putting the least amount of constant tension on the cable. So all my free-play was gone, and wouldn't let the carb butterflies close. Problem solved, and I rode to work this morning with better steering feel and no other issues.

I have met the enemy, and it was me.

 

UPDATE: It turned out that the handlebar issue wasn't the entire problem with the racing idle. And it turns out that 20+ years of tinkering on these doesn't make one an expert (this is not news to most of us).

It was revealed to me again that engineering types like me overlook the obvious, searching for the complicated.

The racing idle continued off and on after last July's post above. I checked again for air leaks, readjusted mixture screws with the Colortune plug, re-synced the carbs, checked the floats, checked the slide vacuum diaphragms, etc., etc.
After yesterday's ride, I pulled in the driveway and parked it while it revved up to 3,500 RPM (from 2,500) by itself! My last idea was, "I guess I'm gonna have to break the carbs apart AGAIN and recheck the throttle shaft seals for leaks, even though I know they're still good."

Then a thought came to me. "The simplest answer is often the best." So... I pushed down on one of the throttle shaft screws, and... it idled down immediately. THE THROTTLE SHAFT IS STICKING. Or the throttle-return spring is misadjusted and doesn't have enough torsion.

Many of you would have checked that first thing. Oh, not me!! I'll waste hours... days, even... looking for other problems.

Either way, it was there the whole time and I missed it, assuming the more complicated, more involved solution was needed. So now I'll just check/adjust/replace the throttle-return spring. And hope there's not a THIRD cause for a recurring fast idle.

Oh, and regarding my overflowing carbs (the original post above)? The tabs on the floats weren't bent far enough (some not at all), which let the floats drop too far when empty. Others have suggested that in other forum posts, and it was accurate for me. The needles probably cocked slightly, and wouldn't align to the seat when the bowls filled up with fuel. I haven't had any overflows since adjusting them to a more reasonable hanging height.

Of course, that's an engineering-type assumption.

 

Just a thought, you have a filter inline between the petcock and the carbs? Not the one in the tank or in each carb, but do you have one spliced into the line?

 

Yes, I have an inline fuel filter between the petcock and the carbs.

 

You really don't.

Electronics can be a problem when they go bad, but they go bad far less often than carburetors get dirty. And you don't need to adjust them.

I have now owned four FI bikes. Only one of them did I do anything on the FI, and really only because I wanted to. It was a $500 bike that was clearly neglected. I replaced injectors and the filter. The whole process took less time than it would to just pull the carbs.

 

My one FI bike woe (2008 WR250R) was a bad fuel pump - there was a bad batch in the early models and mine lasted far longer than most. Just replaced it last year.

 

Love the video. I work in a large machine shop, and this instantly resonated.