few more MPH??

[pwrjnky]

I've got a 2005 yamaha kodiak 450 with only 210 miles and seems to top out around 49 mph. Seems like it should be a little faster. I've been reading about them reaching 55-60 mph. I have no mods at all. Are my ITP terra crosses slowing me down. I'm not racing the thing at all, but seems the should be a little more top end. Thanks

[pwrjnky]

will I get a little more umph if I remove the restrictive exhaust tip and put one on that will let it breathe a little better?

[pwrjnky]

I just changed the plug and managed to get 51 out of it.