Little update here, I tore down my top end today (not much to it with a manual) and my piston rings look good and my piston walls (sleeve, bore wall or whatever the real trem for it is lol) look great. I heard that the oil could be leaking from the valves onto the piston. Well any how I am taking everything to a shop in the morning and letting them check everything out and see what they say. Any other suggestions that might help me???? Thanks everyone!!!!!!

 

hey get a manual, i bought a 06 trx 300ex for$1800 becuse he beat the crap outa it
good deal aye....17 years old

 

sounds like a wrist pin is slapping around in the engine. when this happens it makes noise...louder and louder. then the smoke comes because your rings are wearing in the shape of an egg and oil is passing through the rings.

do a leak down test. break an old plug and screw a 1/4 inch brass air fitting in the top of it. hook it up to a air compressor and put the engine at top dead center(TDC) blow air through the engine and listen where its leaking from.

 

Now that it's apart, someone with a micrometer set should be able to tell you quickly if the cylinder is within spec, if the piston is worn, if the wrist pin has too much clearance, and if the valve stem/valve guide is OK.

To me, new rings would be a given, while it's apart.

 

Ok i took it to the shop today and they told me that i had to get it bored out and the tapping(rattling) noise was the piston tapping the walls. I guess my dore walls got worn down and the piston had room to move. Well anyway i should get my topend back tomorrow and i have the piston and gaskets for the motor just got to get rings. The person at the shop said to take my bottom end off and tare it down to the fly wheel and clean the dirt that got in there through the pull start (recoil starter). He said that mud and water will get throught the little hole that the rope comes out of and make its way inside the motor. Well as i write this I am sitting on my floor in my house with my bottom end beside me lol. There was mud and dirt in the pull rope casing but i cant get the driven pully bolt broke loss for the life of me. so i just took off my starter and looked at the fly wheel (as much as i could see) and turned the motor. As far as i can see there were no signs of any mud or dirt on the fly. I cleand the pull rope casing and sealed that hole since there was no rope anyway so maybe i will be alright. So what do yall think happen to my bore walls. How does it get worn down like that. Well Thanks and i will keep yall updated on how it goes when i put all this back together. Thanks Again!!!!!!!!

 

If indeed you got mud and grit inside the motor, that would have worn the piston and cylinder.

If there's any little bit left in an oil passage, in the oil pump or anywhere else in the bottom end when you put it back together, it won't likely last long.

I don't recall if that machine has an oil cooler, but if it does you might want to just replace it. You can rinse it out with solvent, but there's no real way to know if it's clean or not.

It might also not be a bad idea for you to take the whole bottom of the engine to the shop. You may have some damaged bearings and so forth.

Lastly, if you dunk the thing in mud you might want to see if there's a starter block off cover available (maybe high lifter).

 

Well guys I got my motor back together and everything works like new =)!!!!! Well i just rebuilt my first atv motor and did alright if i say so myself lol. My trusty old Rancher runs GREAT. Thanks for all the input it helped me out a lot. Time to ride lol. Thanks again!!!!!!!!!!!!!!!!!!!!!!!!!

 

Take a REALLY, REALLY good look at your aircleaner. Look for holes and gaps or voids. Make sure everything is mating up and sealing. Have one of your friends over and have them look at the aircleaner also.

Congrates on the rebuild and good job!!!!

 

Good point. Unless the thing has super-high hours, something abrasive made it either through the intake, or into the oil...