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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Flat Spot at Idle
Post Info TOPIC: Flat Spot at Idle
BM Steve


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Flat Spot at Idle
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Couldn't find anything on my problem, I'm sure it's an easy fix but it would be a bit easier if I new where to start.

So never having any carby problems I'm a bit lacking on skills in this area

the bike starts perfectly but just above idle, I mean as soon as you open the throttle and up to about 10% open there's a big flat spot

above that it's all good

flat spot is a lot less noticable with choke on and when it's warned up with choke off

blocked jet,  I guess, but which one ??

any help with pictures would be good

biggrin

by the way, I have done the snorkle and jet mods with std exhaust



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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
hanzo


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I think that will be the the pilot jet as it controls about 25% of throttle and obviously when your chokeing it your adding fuel thats the jet on its own not the main jet on the emulsifier tube .but I would have a good clean on both as a reference point and obviously the easiest route is a good clean through.



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mossproof


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Has it started happening directly after you did the jetting mods, or had the bike been running fine and just started playing up?

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BM Steve


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I did the jet and snorkle mod ages ago, this started about a month ago and got worse

It's been sitting for a while with irregular use.

 

.

 



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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
ttr steve


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Hi Steve

Now this may not be related, but worth a try.

I was out the other day and my bike started playing up, giving a bit of throttle and would die, then it would go again and then die again.

I pulled the pipe of the emulsifier and a load of white oily water came out, I left the pipe of and revved the bike a bit and more stuff came out. When it had stopped I put the pipe back on, and the bike ran fine again.

Doesn't sound the same as your problem, but thought I would share.

Steve



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BM Steve


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Mine is definitely carby related.

I got the exploded diagrams from thumpertalk, so now I know what I'm looking at and which ones to clean.

It's been at least 4 years since I had the carb off so probably due for a general clean and tune in

 

..



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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
ttr steve


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If you need any more diagrams, just ask, I can do them

andrew carb.png

Let us know how you get on.

 



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BM Steve


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I have the thumpertalk ones, they are for the american bikes, don't know what the difference is, shouldn't be much though

 



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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
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