Originally Posted by robmoto
Just a little tip for you , only use suzuki valve stem seals, the after market ones go hard in no time.
3 sets of valves why , maybe tappet settings could be a little tight, and or runnung a little lean, have a look at the colour of the carbon on the valves may help you determin whats going on.
I've used only suzuki valve stem seals and orginal mikuni parts in carbs, learned that hard way...
original valves were replaced when there was some 60 000km in clock, also pistone was replaced by first versize 050 then. I rebuild engine bottom at 85 000 km (if rebember rigt) the top end was like new.
No I have damaged cylinder (heavy oil consumption) and damage in valves. And yes, there were some carburetor problems and some serious overheating while offroading... i was riding too lean.
So i think your dianosis is right.
I'm just wondering how long these valve stems last? Seals for those are easy to change but stem itself reguires some professional help.