GY6 exhaust valve corrosion driving me nuts.

[Robert3165]

I have a GY6 scooter, a 150cc (SUNL). It has 3k miles on it. My issue is the exhaust valve corroding with resulting loss of compression because the valve isn't seating properly until it quits. This is the second head I have installed on the machine (returning the old one when it failed). The valves are properly adjusted during install and the scooter burns nonethanol gas. What I cant figure out is rust and corrosion build up on the exhaust valve within 300 miles. The scooter has been taken on about 25 mile trips so its getting up to temp. I am now down to trying stainless valves. Has anyone else had this problem??

820

Picture is kind of blurry but you can see the exhaust valve on the left and the rust/corrosion build up. I should also say the plug is clean and tan.

[blueboy5000]

That looks like rust. Oil starvation or overheating would be the cause of that

[Gene563]

I had read somewhere about the benefits of upper cylinder lubrication.
I added Lucas treatment to my fuel during my break-in period and occasionally since then.
I don't know if this would be any type of help, or preventative, but I'm just throwing this out there.

[Robert3165]

Its been a month and a half of regular riding with no loss of compression issues so I assume stainless did the trick. I am assuming it came down to bad Chinese steel that was causing the problems.