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Discussion Starter #1
I have a 2013 TW with 4600km (under 3000 miles) it’s mostly stock with the exception of some jetting.
I’ve changed that trying to chase down a hesitation issue.
I went from a 128 main to a 130. I went from a 31 pilot to a 34 pilot.
I tried needles shims. 1, 2, 3, none... nothing really changes it.
I have my air fuel at 2 turns now, but have tweaked that with no change to my issue. It affects idle speed and initial throttle response but that’s it.

I have stock filter and exhaust and have installed new plug.

When riding at lower rpms and I whack the throttle, it chokes, Hesitates, sputters... (whatever you want to call it), then revs up.
The bike idles perfect and works awesome on top end with no fuss.
It’s just the quick throttle opening that chokes it.

What can I do?

I’ve tried a couple different carb slide springs I had in a tool box, no real change.

It’s really annoying.
Please help.



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Sounds like you are overly rich.
Well not necessarily YOU...but the air-fuel mixture sounds to be overly enriched.

Is the inside of your exhaust pipe black with soot?
Do you get any backfiring while riding?
What does your spark plug look like?
Can you start without choke?
Did you have this problem BEFORE you changed jets?

My 01 was completely stock and would go from sea level to over 5000' without issues.
 

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So when you whack the throttle, you’re shifting the potential from the idle jet, to the main jet, but only after around 35%. But if the idle is running rich, that will choke the entire process before the main jet takes over

Wind it back down to a 31 pilot and see what happens ….
 

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Discussion Starter #5
I had the problem before the jetting change. It’s the reason I was jetting.
I thought sure it was just a lean pilot and a lager one with some needle shims and fuel screw tweek and it would be good.

The tail pipe is clean like almost white glove clean.
The plug is clean as well

The cleanest plug pic is the newer one with 50 miles running on the new jetting. The old one was what I removed from before the jets and after. I swapped plugs to eliminate as an issue.

I used to get major popping on deceleration but now that’s almost completely gone. If I’m going down a long hill and off the throttle, I might get one or 2 little pops in 10-15 seconds.
The bike needs a touch of choke to start, but not for long. Also before and now, I needs a little throttle input to fire up smoothly . Like just a little blip as you hit the starter button.


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Try removing the air filter and cover to allow as much air into the air box as possible. This would be a test. It might be wanting a little more air. If this works maybe a higher flow filter may help. It may not do a thing, buts it a cheap test.
Also check all your carb boots for good seals.
 

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Hesitation/balking/stumbling is usually a lean issue, as opposed to blubbering, if rich.
Check for a vacuum leak, which has the most effect at low RPMs.
 

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Pull your petcock and make sure the screen isn't clogged. Replace any other fuel filters you may have. Make sure your fuel line is not kinked.
 

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Hesitation/balking/stumbling is usually a lean issue, as opposed to blubbering, if rich.
Check for a vacuum leak, which has the most effect at low RPMs.
That would be the next thing to check when the signs of "overly rich" aren't there...
Make sure the diaphragm is whole, without cuts or holes and/or isn't pinched under the cap.
Also check float level if you haven't already.
Go back to STOCK jetting and start from scratch to establish a baseline, as I mentioned...mine was bone stock and I had no issues with stumbling or hesitation, so you can go back to stock jetting, since that obviously isn't the issue. Once you've got the problem worked out...you can play with the jetting and note how each change affects performance.
If you try to solve the problem without a STOCK engine...you're going to be chasing your tail for a while.

Here is the test I was told to perform on my old XT225 - which has the exact same engine as the TW (minus the extra long output shaft).
Once you think you have your jetting/carb/exhaust/airbox done right...get the engine warmed up and head for a long, straight piece of road...
Start rolling and shift into highest gear (5th)...and while moving about 20 mph give her full throttle.
She should accelerate smoothly, all the way up to top speed without missing, burbling or backfiring...once this test is successful, you have everything right.
 

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I agree with TW in BC to check your float level. Maybe even raise it a teeny bit. And with SportsterDoc to look for vacuum leaks.

Other than that get a carburetor with an accelerator pump......or live with it. My TW does the same thing when it is cold but once thoroughly warmed up it doesn't.
 

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Discussion Starter #11
I did a thorough carb cleaning, adjusted the float height and even checked it with the clear hose trick. It’s 1mm above the seal.
The bike runs about 95% now. Way better response. I had already cleaned the jets, but this time I stripped it down to a bare carb body and used carb cleaner and air.
I didn’t find any dirt but who knows if it was there.
The float was a bit high so I tweaked it.
That’s a frustrating job.
Anyhow, thanks for the suggestions and pointers.
I’m back to riding.. yeehaw!


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I agree with TW in BC to check your float level. Maybe even raise it a teeny bit. And with SportsterDoc to look for vacuum leaks.

Other than that get a carburetor with an accelerator pump......or live with it. My TW does the same thing when it is cold but once thoroughly warmed up it doesn't.
The TW carb doesn't have an accelerator pump?
 

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The TW carb doesn't have an accelerator pump?
No
Neither did the 1988 H-D Sportster with a Keihin CV carb, but it had a skinny (rich) needle to compensate.
That needle (N65C) then became the cure for 1989 up carbs with hesitation from low to mid-range.

There are several parallels with the Sportster constant velocity (vacuum operated slide/needle).
Typical changes to a new Sportster, jetted very EPA lean were:
Change pilot from 42 (0.42mm) to 45 (a 48 would bypass changing the needle, but don't expect it to idle at 8,000 feet elevation)
Open mixture screw to 2 1/2 turns (I liked 2 3/4)
Many changed the main jets unnecessarily. I did so only to reduce engine oil temperature running sustained WOT up a steep grade

However, my TW did fine up to 8,500 feet (that is as high as I had it) with only opening the mixture screw.
 
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