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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Ttr running rough
Post Info TOPIC: Ttr running rough
Jordandenton


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Ttr running rough
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So I was out with the TRF today and about halfway through the day the bike starts coughing and sputtering and then dies.

Thinking it was lack of fuel I put it on reserve, I manage to get it going but then it still didn't run properly and died again.

Got it home and looking round it I can't see anything obvious I've had the carb off and the jets are all clean and the bowl is clean too.

It has a spark although not massively bright,  the air filter is ok and fuel flow is good, but when running it coughs and splutters when bring revved I'm well and truly baffled tbh

Cheers in advance 



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TTRfan


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Bad luck Jordan cry

When you say the jets are clean, did you ream the pilot jet with a bit of copper wire? Notorious for looking clean but still being partially blocked.

It is rare for the main jet to block so I am puzzled as to why it doesn't rev.

No water in the fuel?

When you say fuel flowing freely, is that when you undo the carb float bowl drain?

Brian



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jasparach


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Will it run with the choke on?


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ttr steve


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Main jet blockage by the sounds of it.

This is a bit weird though, I had the same symptoms a while ago and thought balls, I am going to have the carb off mid ridecrycrycrycry But I took the pipe of the emulsifier and loads of oily / watery crap came out, I revved the bike for a bit and lot's more came out. When it had stopped I put the pipe back on and the bike ran perfectlyconfuseconfuseconfuseconfuse I am still confused to this dayno

As Bri has stated drain the fuel out of the bottom of the carb to release any water contamination.

Steve



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ttr steve


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And check that pesky carb inlet stubbfurious



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Jordandenton


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The main jet looks cleans enough to be brand new and it's the same for the idle jet too.

It starts when the cgike is on and runs but when reving it just runs rough almost like it's bogging down.

The fuel flowing from the carb drain is clear and a good flow on it.

I will check the emulsifie tomorrow 

The only other thing I can think of is if the coil or spark plug cap is breaking down



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TTRfan


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Did you try it with the choke on?

Also, did you actually pull the pilot jet and ream it?

Very very unusual but I did have a customer who spent ages trying to sort out a misfire that turned out to be a problem with a loose or broken resistor in the plug cap.

If all else fails, check the cam timing is correct. It involves getting the tank and can cover off but.........



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Jordandenton


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Yea with the choke on it'll start but doesnt run properly.

Yep all the jets were pulled out and put some wire down them.

Also I checked the timing and that's bang on.



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jasparach


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What colour is the plug tip if you take it out for an inspection to see what is happening with it?

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jasparach


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www.motorcyclecruiser.com/motorcycle-jet-kits-carburetion-basics

It might be of help to you diagnosing what jets do what in the carburettor and where they might affect it.

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1996 TTR 250 OE, 1996 YAMAHA WR 200, 1990 YAMAHA FZR 1000,2001 HONDA DEAUVILLE 650, 2005 TTR 250, 1998 Honda CR125R( in pieces) 1994 Kasawaski KX 250.
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