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The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Difficult start
Post Info TOPIC: Difficult start
TTRinEgypt


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Difficult start
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I have a strange one here... I had my bike sitting for quite a while (years) and took it out a while ago. I cleaned out the carb, airbox, oils etc and put in a fresh plug. For some reason it is very difficult to start. It starts with choke full out, but dies immediately (2 secs). And dies even quicker if I try applying any gas.

Once I do this a couple of times (to give it a chance to warm up slightly) it start normally. Then, if I let it cool down after a ride (for a half an hour) it acts up again!

Any ideas?

Cheers



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Cubber


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At a guess, I'd say it was carb. gunge. cry

Sounds as if at least one of the jets is blocked (or partially blocked). bleh

The holes in the main and pilot jets are very tiny and are easily blocked. Don't be tempted to clean them by threading wires through or they will be damaged.

Best method is to put them in an ultrasonic tank, but copious carburettor cleaner spray applications are a cheaper alternative. Repeat as necessary. aww

I take it that, after laying up for the years, you put fresh fuel in the tank. confuse

Martyn



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East Budleigh. Devon
TTRinEgypt


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Thanks, Cubber. I'll take the carb apart again...
I did put in fresh fuel after cleaning the tank out. What else it does, is that it misfires occasionally. Once it is warm and seems to run ok and I adjust the idle speed to normal, it pufs a couple of times and dies, but starts right up again...

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TTRfan


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I am sure Martyn is correct regarding one or more blocked or partially blocked jets.

Another possibility is that the carb float valve is sticking. The way to check this is to open the drain valve at the bottom of the float bowl (make sure you have a container under the overflow pipe to catch the petrol!)  and check that there is a constant flow of fuel through the carb.

Good luck and let us know what you find please wink

Brian



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Exeter, Devon, UK

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TTRinEgypt


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OK, jets and orifices thoroughly cleaned, but no noticable change.

It starts with choke, but dies after 2 sec, or any attempt to apply gas. After 10-15 attempts, it catches on, and works ok once warmed up. It still misses occasionally and dies if revs are low. Also, idle is not stable. Need to adjust idle adj screw up and down, as idle drops or it starts to race...

Could it be a vacuum leak? I will take out and inspect the intake rubber/carb mount dealie today...

What is the recommended idle mix screw adjustment? How many turns out?



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Yuraku


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I bet it'll be a leaky manifold to blame - rubber/metal bonding maybe miffy on Mr Yamaha's TTRs. biggrin

Yuraku



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