First, the bike is a 2009 KLX250SF, Don't even have 300 miles on the bike yet however I think I hear a knocking noise in the engine. I've tried to research this out but I've come to realize I'm going to have to get some input. FYI I just want a good idea of the issue before I head to the dealer.

What is happening is when the engine starts to reach ~5500+ RPM during acceleration after I hit 3rd or 4th gear I hear what I believe is a knocking noise from the cylinder. Now seeing as its break-in period I try not to run the engine beyond 4000 RPM anymore then I must, but either way it's there. It doesn't happen when not in gear or in lower gears.

I'm wondering if I'm being paranoid or if it's a legit issue, it's been a long time since I was on a bike and I can't claim I would know exactly what to listen for, but it deffinently sounds abnormal.

any ideas before I head to the dealer?

 

so, a good chance of detonation while under a loaded condition. Up the octane and try that. What is the bike?

edit- I see your edit now and it seems like your ride would be lugging away in 3rd gear at 4k rpm. But we will need to hear from the klx guru's.

 

I suppose I can try a different brand, already running premium (93) here in NC. But it's been from the same station.

 

I am going to copy this thread and post it up in the klx section since there have been no guru's noticing this thread yet.

 

My 2006 (bought new) did the same thing, after a while it went away and caused no problems.

 

Let it rev a bit more. The break in that Kawasaki has "recommended" for the past 40 years has seemingly never changed. They even recommended not going over 4000 rpm on the triples... do that and they'd load up so bad they would barely run.

Break in is about varying engine speeds without lugging or overreving the engine. Work your rpm between 3000 rpm in easy going, 4000 in harder running to maybe 7000-8000 max for about the first thousand. Best break in is riding back roads in a comfortable way without lugging the engine.