no top end

[presterminator]

well i'm new to riding but i just bought a 93 kx 125. anyway when i first got the bike it felt like it had a lot more power. the guy i bought it from said that it might need a new spark plug soon. well he gave me a spare one and i was wondering if a bad spark plug would hurt power?

 

[PINGERS4LIFE]

yes a bad plug can effect the topend i would replace it and see how it runs

 

[matt-itude]

How would he have known if he hadnt been having problems with the plug? thats beside the point check the plug color when you pull it and change the bike over to your favorite/a good oil.