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xt350 finally took off top end, yikes!!

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hi, been a while since i requested help and advice, but i finally tore the top end apart and the piston was shot. see pix, in profile... i found all the replacement parts at south seattle sports plaza, ( advice from somewhere here in forums, it really was the cheapest price anywhere!!! :) ) i got everything for the top end there, piston, rings, pin, clips, gaskets and a few other piece parts for under $160.00 including delivery.

i presently just glass beaded the jug and painted it high temp black, and am dropping it off at the machine shop this morning, meanwhile, cleaning and painting up all the other stuff.

thanks to all that gave me advice and help in the past, this project is much easier than i thought,

i hope to have more updates soon

my 2 year old son (one of the triplets rest are girls!! ) is my big helper! and had a blast helping me, i just hope he didnt drop anything in the crank case while i wasnt looking!

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host the pics on photobucket. they post much easyer that way. that is how all mine are done on here.

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ouch! that is not pretty. looks like it ran way lean. carb boots ok?

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suprisingly, the boots are perfect! the bike sat for many years in a storage locker then sat outside for a couple years covered with a tarp. (previous owner has told me....) only 3100 miles as of now, local mechanic told me that sitting so long is what probably did it in, i pressed into service "gently" but after about 120 miles, this is what happened.

bike is very clean for age and storage issues, i am very anxious to get it running, but need to be patient and follow breaking in rules very carefully.

i have not messed with the carb, it seems to work nicely, after i get it running again, i hope to do the little trick i read somewhere in here about drilling out the little cap on the side of carb and readjust it.

more pix soon.

any more advice or ideas for cheap performance while its apart?

I polishe the crown of the cylinder head with a dremel tool it is nice, smooth and shiny now. i "wire wheeled" the ports and used a flexible plumbing/heating brush to clean out the exhaust pipe

i took a gamble and used high temp BBQ grille paint, the guy at the local paint shop said that it is supposed to withstand hotter temps. and it has a nice "sheen" to it, the paint looks nice, we will see if it burns off! at least it will smell like i am cooking a steak or burgers.

more to come.....

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ouch! that is not pretty. looks like it ran way lean. carb boots ok?

I have to agree with Maim. If your boots are good I would take the carburetor apart and check the jets. If the carb had any gas in them at all while sitting it probably varnished the jets. Better to be safe than sorry and end up with the same thing in another 120 miles. You might check the screen in the petcock of the fuel tank also.

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i didnt know that would make the piston and cylinder fry like that. i thought that would be a dry oil result. just as well, the machine shop told me the local yamie dealer told me the wrong size piston to get. i have to ship it back to washington state, eat the shipping, restocking fees, etc.... and prolong the wait for at least another 12 days of ordering and shipping. i was afraid to tear the carb apart since i read in here they are very "tempermental"

i will tear it down, polish the outside with the dremel and try to rebuild it too.

i am sure i read somewhere in here about doing that in past posts.

thanks for replies again.

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I would have said no oil too. My cylinder looked very much like yours It had been using oil for a while(rings), and I forgot to top it off and had a mild sieze. Wasn't quite as bad as yours, but close enough.

It might not be a bad idea to check the oil pump since you have a little more time now. They use plastic gears and mine was pretty worn out. It didn't fail, but the gear is cheap and I put a new one on anyway. I also took it apart to make sure there wasn't any junk in it. Check the oil screen that's on the bottom of the case too.

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boy this has turned into pandoras box. murphys law all in one!

parts are all ordered, i am going 1mm over on the piston, does that mean i have to rejet the carb and how does that affect the horsepower?

since i have the time, i am going to do a little more detailing and maintenence.

what exactly would have caused the piston/rings to get like that? the motor smoked really bad for a while, thought it was valve seals, but it stopped after a while, i assumed they got "moist" again and the bike ran great.

the oil change only had 100 miles on it. cleaned screen and all. the "window" is hard to read, glass is cloudy. so i drained completely and poured in exactly what the manual said. ( it ws like 1.48 quarts.)

more as develops....

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Oil related failure for sure, not jetting. Most likely a ring seized, ending your day. The damage was probably done before the last oil change.

+1mm will not affect the jetting at all.

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