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2004 yz 85 rich or lean?

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I bought my son a 04 yz 85. I test rode the bike down the street when I bought it and it ran ok, hesitated a bit but did feel strong when it came on. I thought dirty carb. The bike was in great condition so I bought it. Got home cleaned out carb and bike runs better but still not clean. It is stock except for a fmf turnbine core silencer. It is drooling oil out of the silencer but plug appears to be tan. If you give it too much throttle quickly it dies, if you are rolling on the throttle and hit the pipe it runs good but if you back off it feels like there isn't any gas there. Is this a jetting or float problem? Help! Thanks.

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if its drooling oil its probably ritch. it sounds like you might just have to move the needle down though.

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First things first, make sure the gas is fresh or your wasting your time. If your'e not sure drain it and fill with new, second replace the plug and go from there. It is normal for a 2 stroke to spooge a little not to much very little. If the old plug is tan then probably just old gas, also I run some amsoil quikshot every 3 or 4 tanks to keep the carbs clean in all my bikes, just cause cali gas is terrible.

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Are you running the same premix ratio as the PO?

Does it splutter before getting on the pipe or just die.

It could have been jetted for warmer temps.

As stated before, start with fresh gas and a new plug.

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Kind of sounds like my kid's bike when I first got it. I did some research--these bikes come very rich from the factory. I leaned pilot, main, and lowered the needle and it ran much better--less spooge and cleaner/crisper when running at lower rpms.

Check your jets sizes against what came stock and lean a little at a time to see if it cleans up the bottom end and spooge--also compensate for your altitude and premix ratio against stock jetting.

Keep in mind--in stock form--the YZ85s do not have a very linear power band--they lack bottom end and have a hard mid and top--this can be confused as a slight hesitation also. The engines favor the more experienced racer and are not intended to be lugged around. :lol:

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Thanks everyone. I will try some of the suggestions. It is old gas that I started with. I did add some fresh gas but I guess I should drain it and start fresh. It definitely wasn't a hesitation in the powerband because I had to actually back off on the throttle and then turn it again and it would kick back in.

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