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Post Info TOPIC: Bike smoking when warmed up


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Bike smoking when warmed up
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Hi guys,

just got my 2005 Up and running after a tidy up in the workshop.

Starts lovely and runs well from cold. Left it to warm up to change the oil but once warm it smokes quite a bit, puffs as it is revved I would say white or blue. Im not sure how old the fuel is but I will change this. 

was thinking of doing a compression test, will this tell me if it is valves or rings? 

anyone else with any other ideas to check? 



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Ok so warmed it up this evening to do a compression test. Smoking straight away from cold now.. I would say white smoke, filled the workshop within a minute so had to run it outside.
Took out plug and it looked oily.. (brand new plug so only run twice in workshop)
Carried out compression test holding throttle fully open and 170psi shown. So well within what it should be.
Tempted to give it a run on some fresh fuel and see if it clears.
Otherwise check Valve clearances?

Could it just be carbon deposits on valves letting in oil from it sitting not being used for 6months?

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Super Guru

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stem seals common good compression though

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Super Guru

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Definitely give it some fresh fuel anyway! Fuel will be quite stale in a plastic tank after 6 months.

What condition is the air filter in?

Could easily be stem seals as John suggests. I have just been rebuilding an old Honda TL250 with the same symptoms. Actually turned out to be a loose valve guide, but a hardened valve stem seal would allow oil past in the same way.

Good luck!

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Air filter brand new twin air.

I started it again tonight after compression test, started instantly and stood idling for a good while with no smoke. As soon as I opened throttle it started smoking straight away and then continued.

I held it at 1/4 - 1/2 throttle for a few mins to get some heat into it and see if it would clear the smoke, downpipe was glowing cherry! I guess it is running lean? Will drain the fuel and take carb off and inspect it.

How hard of a job are stem seals?

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I have heard glowing pipe can also be rich running - from fuel continued burning in the pipe instead of in the combustion chamber, but I don't know if it is true or just "internet diagnosis"
Stem seals - ok if you have the right tools, patience and general skills!

Brian's cylinder head rebuild sticky here: www.ttr250.com/Rebuilding_cylinder_head/TTR_cylinder_head_rebuild.htm
His cylinder head removal sticky here: www.ttr250.com/Removing_Cylinder_Head/TTR_head_removal.htm



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I have had a similar issue and spent ages messing about with the carb, etc.

Turns out TTRs don't run well on diesel and even a small remnant of it in your petrol tank or can can create quite a smoke haze!

Just a thought.......



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Thanks everyone, will start by changing fuel for fresh superunleaded, then will look at carb and stem seals.

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