I'm brand new around here. In fact, this is my first post. Hopefully I don't get ripped apart.

Long story short, I'm an old guy who's new to riding. Picked up a 2008 KFX 450r. I really like it, but I need more low-end speed. I don't know anything about fixing, upgrading or maintaining any type of motor, but I'm willing to learn and I'd like to make a project out of this bike. I want to start small, though. The only thing I've done with my new ATVs is change the oil and spark plugs. That's about the limit of my knowledge. I did shear all 4 of the bolts on the rear sprocket of the KFX, but that was just a matter of replacing them with bolts from Lowe's and tightening the chain (which was quite the learning experience).

All I know is that I'm running a 14/37 sprocket combination and I have some sort of aftermarket steering stabilizer on the quad. Other than that, any add-ons are cosmetic, I think.

I need more bottom-end speed because I'm trying my hand on the motocross track and I don't seem to have the start speed that others do. A small berm, followed quickly by a large jump... I just can't get speed. Admittedly, some of that may have a little bit to do with me being kind of a puss.

Obviously, I'm looking for things that can help me out off the line, but I'm also looking for upgrades that can help out overall performance. Knowing what you know as an experienced rider, what would you suggest to someone new, keeping in mind that they have to upgrade without much assistance and no experience.

I'm more than willing to do the research on installation (YouTube is my friend, as are these forums) and I have a buddy who knows very little that is willing to help me out with installing new parts. I'm just looking for a good place to start. I want a bigger, badder, stronger, meaner bike and I also want to learn engines... a little bit at a time.

Your help is greatly appreciated.

 

taller rear sprocket will gain more low end, but it will also take away from ground clearance.

Be certain to get the same grade bolts, if it has 3 marks on the head it is a grade 5, if it has 5 marks it is a grade 8.

 

welcom to the forums! you're not going to get ripped apart! we're not a bunch of sharks waiting for a feeding frenzy when a victim presents themselves we're here to help. once again, welcome.

 

Quick get him!!!

seriously i would leave it with stock gearing until you get used to the bike, unless you need to replace the sprockets.

 

Welcome to the forums.... Hope you are able to find what you need.

As for improving the bike, I'd say you should start small and upgrade things that will help all around first. I'm not a big fan of replacing pipes due to more noise, but that would be a start, then maybe a fuel map upgrade and air filter upgrade.
That's about all you can do to the engine without breaking into it, which I don't think you want to do to gain VERY little HP per dollar. Not to mention it reduces the dependability of the bike as well.

Sounds like you want a bit more umph from takeoff, but these 450's set up for MX are pretty hot already. They are tall geared, but rightfully so. That way you don't have to shift every two seconds and have more time to keep power going to the wheels. Sounds like you just need to rev the crap out of it out of the turn. Remember these bikes are made to rev a lot higher than something like a 400ex or the raptor that was originally designed for trails. They are similar in ride design as the two strokes so they have to rev to make power and shoot you out of those corners.

Money spent on a MX bike is best spent on suspension upgrades hands down. Another thing you might want to consider is different tires for the track you ride. Stock tires are good for general use, but a good set of biting MX tires will surprise you as to how much power these bikes loose to spinning that would otherwise be used to propel you forward over that big jump your talking about.

I know that might not be what you want to hear, but If I were spending the money, that's where I'd put mine.