KX80 '89 (WaterCooled) Excessive Oil

Hi All,

While at the track a while ago, my '89 KX80's powerband disappeared, i continued to ride without it for a while, and eventually the bike died. I'd try start it straight away and get nothing. If i left it a minute it would start 1st kick and stay running for 5-10secs. I've tried different spark plugs and it's the same result.

While reving it up on the stand just now for like 5 secs, i looked back at the wall 1m behind me and noticed it was covered in oil! This bike has always spat alot of oil out the exhaust, but i never thought to this extent. I then took out the plug and smoke came out the cylinder, for quite a while. I then put in a different plug and ran it for a bit and it died after 10-15 secs, and oil had somehow gotten out the edges of the spark plug(apparently i hadnt tightened it enough). I've come to the conclusion, that the plug is being fouled and can't ignite anymore after these few secs. And yes the plugs are black and not dry.

I've been running a 32:1 mix since i got it about 2 months ago. Going to change to 40:1 from now on. Spoke to a Yamaha mechanic, and he recons i should clean my exhaust, burn out the excess carbon, repack the silencer, and clean my powervalve. (and change the fuel)

What i would like to know is what is the process of doing this?

I'd think i need to drain my water, take the head off, take the power valve out? or leave it in there and clean it. Have never been inside an engine yet so please bear with me. What can i clean the power valve with? Is there anything else in there that would need cleaning from all the oil?

Any help is appreciated!

Thanx, BirDMaN

I would strongly suggest that you start by getting a service manual. Not only does it tell you the steps, but it also has important measurements to check while inspecting it.

The general consensus among most people here, is that if you recently bought a 2-stroke and dont know the total history of the bike, its best to refresh the top-end right after you purchase it. The top-end usually involves a piston, rings, gaskets, etc. After you disassemble and measure everything, it might require more. I would suggest ordering a service manual, along with the top-end parts, roll up the sleeves and have some fun! A KX80 will need top-end replaced on a fairly regular basis, so you might as well get used to it. You will also need a decent micrometer to take measurements with.

Make sure you inspect the cylinder for damage. It may look good but if you don't take proper measurements and you just throw a new top end in you will be wasting your money. I would not go to a 40:1 mixture. 32:1 is what is recommended. You can make changes with the jetting, but you will need to inspect your plug after making changes. Look for a consistant brown color. I will bet that your pwer valve is stuck open with sludge, so that will have to be cleaned. Repack the silencer like you said. Have someone look at your cylinder if you are not sure what you are looking at. This bike requires you to be on the pipe. Its not a trail bike. You could buy a new powerband, I think they come in green, blue and hot pink, LOL. Seriously, start with top end. Good luck.

Thanx for the replies.

I'm on a tight budget, so really don't want to be forking out cash for parts, they are mighty expensive for me here in South Africa. Will be selling the bike soon enough anyways. Have been buying cheap 2nd hand bikes and putting work into them and selling them for more, to get cash to buy a better bike, and repeat. When i've sold my current bikes and got myself a decent 250 i'll be willing to put money into it and keep it for long.

For now i will clean everything up and hope for the best!

Good Luck

Turns out the oil issue was that the muffler packing was soaked very badly and i was running a little rich on the pilot. The reason the bike was dying after a few seconds was that the outer stator section had ripped the holes it bolts to the magnet section so it was loose on there. Got it welded by noob mechanics who welded it on so it wobbled when turning, eventually got it welded perfectly centered and changed out the muffler packing and the bike is running 100%! :thumbsup:

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