My KX550 is straight stock. Running down the interstate with the tack at about 5500 RPM, I twist the throttle. The bike feels like it sags and then pulls away strongly. If I do the same thing at 4500 RPM it just pulls away strongly.
I think the main jets are lean. So the question is why? And what could make it happen. Stock exhaust, stock, carbs, stock airbox????
I first noticed it about 8 months ago after replacing the airfilter. I had owned the bike about 4 months and was doing a tune up. New plugs, air filter, such as that. When I looked at the old filer it was oil soaked and had big holes in it.
So I am wondering, should I rejet, or figure out why it is running lean. And what are the things that could cause the running lean assuming the jets are correct.
Thanks.