fouling plugs

[lumberjack]

 any thoughts on why my boy's rm 85- 2 smoke keeps stoping after every 2 hours of hard rideing, the plug is fooked every time it's costing more in plug's than fuel  , the 2 smoke oil is the best, the mix is spot on at 40-1, cleaned the air filter gone down 2 on the jet in the carb to 125, engine is good inside, gone from a 10 plug to a 9, dont know what else to try

[Day7936]

Try different type of oil mate wen I had my ktm 200 first I ran it on silkoline and it didn't like it one bit kept on gumming the plug at 40-1 but then I changed it to motorex and leaned her out to 55-1 and she ran perfect either that or try a fuel additive like boost to thin the mix only trouble with that is the rings wear more quickly

[lumberjack]

Try different type of oil mate wen I had my ktm 200 first I ran it on silkoline and it didn't like it one bit kept on gumming the plug at 40-1 but then I changed it to motorex and leaned her out to 55-1 and she ran perfect either that or try a fuel additive like boost to thin the mix only trouble with that is the rings wear more quickly

   ill try silko

[jasext]

Agree, try different oil and drop the amount in the mixture, old 200 ktm i had would run sweet on 85ml oil instead of the usual 100ml in a 5 litre mix, also had a gasgas 300 that i found to be the same, ran both on Putoline