Carburetor Acting Strange...

mq1991 · 06-15-2016, 09:30 PM

Hey everyone! Need some advice on my carb tuning..

Heres the deal:

- Jets are 25 pilot, 110 main, needle clip is on the 4th spot down from the top.
- Carb was just cleaned
- Checked for air leaks with a propane bottle, couldnt find any.

My idle mixture screw is making me scratch my head, If I have it open at all, the bike idles way too high and I cant get it to come down (3000rpm ish). If I put the choke ON, it brings the idle down to almost perfect.

I tried completely closing the idle mixture screw, and now my bike idles at 1800rpm almost perfect, every once in awhile ill blip the throttle and the rpm will settle back down after a WOT run.

Any ideas on why this is happening? The video is with the idle mixture screw completely closed.

'16 TT250 · 06-16-2016, 12:41 AM

Have you tried backing out the idle speed screw? Also make sure the throttle cable isn't too tight and holding the slide up.

Adjuster · 06-16-2016, 09:19 AM

Sounds like possible air leak into the carb.

/

'16 TT250 · 06-16-2016, 10:39 AM

The link to your video doesn't work for me, being able to hear it might help if other suggestions given don't pan out.

mq1991 · 06-16-2016, 12:36 PM

Quote:

Originally Posted by '16 TT250

The link to your video doesn't work for me, being able to hear it might help if other suggestions given don't pan out.

Wasnt sure if it would work unlisted... lol should work now.

pcspecialist · 06-16-2016, 01:28 PM

Open up the stock carb, put the 110 in it, shim up the needle with three #4 washers, turn out the idle mixture screw 1 5/6 turns.

newrider93 · 06-16-2016, 11:21 PM

Before you mess with the carb anymore I recommend you check the pipe from the air box to the carb. When I first got mine I had an air leak where the pipe goes into the air box. Check that seal there. Mine had pulled away from air box so I just resealed it. No issues after that.

dpl096 · 06-17-2016, 08:55 AM

Quote:

Originally Posted by newrider93

Before you mess with the carb anymore I recommend you check the pipe from the air box to the carb. When I first got mine I had an air leak where the pipe goes into the air box. Check that seal there. Mine had pulled away from air box so I just resealed it. No issues after that.

He's absolutely correct. If the carb boot has failed in any way it wont matter how much you tune on that carb it'll never be right.

06-15-2016, 09:30 PM	#1
mq1991 Join Date: Mar 2016 Location: Gurnee, Illinois Posts: 277	Carburetor Acting Strange... Hey everyone! Need some advice on my carb tuning.. Heres the deal: - Jets are 25 pilot, 110 main, needle clip is on the 4th spot down from the top. - Carb was just cleaned - Checked for air leaks with a propane bottle, couldnt find any. My idle mixture screw is making me scratch my head, If I have it open at all, the bike idles way too high and I cant get it to come down (3000rpm ish). If I put the choke ON, it brings the idle down to almost perfect. I tried completely closing the idle mixture screw, and now my bike idles at 1800rpm almost perfect, every once in awhile ill blip the throttle and the rpm will settle back down after a WOT run. Any ideas on why this is happening? The video is with the idle mixture screw completely closed.
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06-16-2016, 11:21 PM	#7
newrider93 Join Date: Jun 2015 Location: Missouri USA Posts: 164	Before you mess with the carb anymore I recommend you check the pipe from the air box to the carb. When I first got mine I had an air leak where the pipe goes into the air box. Check that seal there. Mine had pulled away from air box so I just resealed it. No issues after that. __________________ My YouTube channel where you can check out my hawk and other cool stuff: https://www.youtube.com/c/Andrew93 newrider93 AKA Andrew93
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06-16-2016, 12:41 AM	#2
'16 TT250 Join Date: May 2016 Location: Hacienda Heights, Ca Posts: 281	Have you tried backing out the idle speed screw? Also make sure the throttle cable isn't too tight and holding the slide up.
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06-16-2016, 09:19 AM	#3
Adjuster Join Date: Dec 2014 Location: Deerfield Beach FL Posts: 1,410	Sounds like possible air leak into the carb. /
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06-16-2016, 10:39 AM	#4
'16 TT250 Join Date: May 2016 Location: Hacienda Heights, Ca Posts: 281	The link to your video doesn't work for me, being able to hear it might help if other suggestions given don't pan out.
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06-16-2016, 01:28 PM	#6
pcspecialist Join Date: May 2016 Posts: 583	Open up the stock carb, put the 110 in it, shim up the needle with three #4 washers, turn out the idle mixture screw 1 5/6 turns.
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