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Discussion Starter · #1 · (Edited)
I'm new here, so hello everyone.

I bought a 2003 Honda 300ex the Monday after Thanksgiving. I did a test ride and looked the engine over for any sign of oil/gas leaks. It ran very strong and I didn't find any leaks. The guy that I got it from lived less than a quarter mile from me, so I paid him and took off on my first ride. A couple of days later It started to run rough at full throttle. A few days after that it started to pour oil. I took the gas tank off and gave it the white vinegar treatment to remove rust and any build up. I washed out with water and sodium bicarbonate. Next I filled the tank with ethanol free gas. I shook the tank around and immediately dumped it out. I also cleaned up the petcock and made sure that gas would pass through it. I put the tank back on and fully expected it to run better. It ran after I got back together, but if anything it ran and smoked even worse. It also wouldn't idle. I accidentally let it go dead while trying to shift it into reverse and it wouldn't crank back up. This morning I went throught the whole process to hopefully get it going. It cranked after I shot a little starting fluid to it, but it ran rough and smoked like a loaded freight train. The minute that I let go of the throttle it died again and wouldn't start again. I can't even to begin to look for the oil leak when it won't stay running so right now all I have is a 300+ paperweight. I'm not a mechanic by any means so I was hoping someone here could offer an idea what is going on with it. I've had the thing for a month and only got to ride it 5 hours or so. I'm so disgusted with it that I can't even stand to look at right now. Any advice on how/what to check would be greatly appreciated.
 

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Start by opening things up. Check valve adjustments, do a compression and Leak Down test.
Monitor the oil level. If its going up, you have a leaking fuel valve and float valve in the carburetor.
I've seen instances where one of the jets in the carburetor have fallen out which will cause huge
problems. Check air filter and air box for obstructions too.

Mad
 

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Discussion Starter · #3 ·
Start by opening things up. Check valve adjustments, do a compression and Leak Down test.
Monitor the oil level. If its going up, you have a leaking fuel valve and float valve in the carburetor.
I've seen instances where one of the jets in the carburetor have fallen out which will cause huge
problems. Check air filter and air box for obstructions too.

Mad
Thanks for the reply Mad. The quad is going to have to wait a little while. I came down with Covid 19 the first week of January and it turned into pneumonia. I'm doing better, but I have to see a respiratory therapist tomorrow. It looks like it'll be a while before I can walk to my bike, nevermind working on it.
 

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Oh no. Well I certainly hope you're getting better. So far the wife and I have avoided it. I guess living in the mountains
with nothing but bears and squirrels for neighbors ain't all bad. When you get back to it feel free to ask questions.

Mad
 
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