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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Please help - TTR dies after 20 minutes running????
Post Info TOPIC: Please help - TTR dies after 20 minutes running????
jonp


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Please help - TTR dies after 20 minutes running????
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I bought a used 2006 ttr250. Bike looks like it is is phenomenal condition very little case wear marks engine looks clean, took the tank and seat off and cleaned out the carb all look practically new.  Problem I am having is that the bike starts up fine with choke runs great for about 20 minutes then just dies and will not restart until the bike has cooled down.  I am not sure what would cause this kind of issue.  the bike is stock and has the factory 50 pilot jet.  I also live at about 4500' ASL.  I cleaned and oiled the air filter and I even tried to start it with the airbox cover off thinking maybe it was an airflow issue but it did not help, removed the spark arrest with hope if it had the ability to breath it would help, trying to rule out that the altitude might make it run rich and letting it breath would help lean it out since I do not have any jets to try that.  What could be causing this?  Thank you



-- Edited by TTRfan on Monday 16th of February 2015 08:54:45 AM

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Terrence R


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RE: Please help
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Sound like a fuel delivery problem. Could be the tank pet**** valve, low float height too low making the bowl run dry quicker than it can fill up. But I bet that it's the breather on the gas cap. Try starting the bike with the gas cap off the tank.

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jonp


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ill try that, why do you think it runs fine for about 20 to 30 minutes before the problem occurs? I was thinking maybe the valves are tight and when they get hot they expand and seize up. plan on checking the clearance to verify, the other thing I thought is maybe the CDI goes bad when it gets hot. Never seen a bike run perfect then just die, this happens every time I ride it so Its not an isolated incident. I also have new fuel in the bike.

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ttboof


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the tank breather is the next place to check , it takes about 20 mins to use enough petrol to create a slight vacuum in the tank and stop the fuel flowing . 

float level and cdi would  tend cause a problem much earlier ,



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jonp


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I have been reading that that could be a cause. Any mods for the cap to open it up to breath better?

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TTRfan


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A while back I had a look at some spare petrol caps. Using a short length of clear pipe I was able to easily blow down through all 3. There was no feeling of restriction and I could get a lot more air through than even the biggest jet could pass petrol.

I therefore don't think it would be necessary to mod the cap once it is cleaned and working as Mr Yamaha intended. 

The photos below show what the mechanism looks like. Very simple and just needs to be clean wink

Brian

 

Blue petrol cap dismantled 001.jpg

Blue petrol cap dismantled 002.jpg



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jonp


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RE: Please help - TTR dies after 20 minutes running????
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Thank you for the help I'll try that in the next few days. Hope it's that easy.

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jonp


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So I cleaned out the fuel cap and tried to start the bike but it started and died within 2 min. Ran fuel out of the pet**** and it flows free. Noticed when the float bowl drain was opened no fuel came out. Took the carb off and cleaned everything out. Went to check the float hieght and noticed that someone had tried to repair a broken float bowl post. When checking the post it broke off again. I am attempting to fix it now. Not sure what to do if i can't get the post fixed. Saw that a new carb is $400 dollars. Any suggestions?

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Markvan


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There was a carb. Ebay Australia. $150 au.  But postage maybe a prob. 



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 Tweed heads Australia. 
Cubber


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A post was shown HERE in August 2012 regarding a repair to the float pin.

It is described plainly enough but, unfortunately, the pictures were no longer there. disbelief

I found some copies and put them in the post - but not all of them no

Martyn



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jonp


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Thanks for all the advise. I was able to use fuel resistant adhesive to re-seat the post and made sure the float bowl was the correct height, I cleaned out the carb completely and reassembled, verified fuel flow and the bike has started up and is running good. Not sure if it was the fuel cap the float post or a combination of things but you guys definitely got me in the right direction so thank you again.



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