so i finally got use to my 2004 kfx 700 it seems to be run good and it has alot of potencial power, but for some reason when i ride up hill or a flat surface my top speed seems to be only around 40mph which is i did a research that my kfx 700 suppose to be exceeding a top speed of 70mph + but when i do ride downhill it seems to be going pretty fast like i could hit 60mph + easily.
i know an older lady used to own this and the husband mentioned that she flipped it twice trying to do a 360 and broke the right side of the fairings but i inspect everything nothing bend or crack on any parts besides the plastic fairings.
could somebody help me to fix this problem? its pretty sad when im following a 250 honda recon and all i see is taillight fading away! thanks for your support!

 

sounds like its jetted wrong, pull the plugs and see if its black-too rich brown-about right white-too lean then go to larger or smaller main jet, adjust air fuel screw, ect check air filter too

 

Could be lots of things.
Is it box stock? If so it could be like Kerbbirds said. Jetting is very important with the 700.

Could also be things like the clutch. How does it run?

 

I just found out that the foam filter is missing only the metal screen is on and for some reason it look like the muffler has been tap a little I guess to get a better free flow.
I just hope that the problem is just the jetting!

 

Holy F.......reaking hell. NO FILTER?

If you rode where I do, that engine is done, even if rode for like 15 minutes.

Do a leak down. Bet you get a hurricane out of the crank case!!!

 

I guess the best thing is bring my quad to a mechanic!

 

That would probably be a good idea.

 

The lack of a filter is not good but it doesn't necessarily mean your motor is junked. No filter with stock jetting is going to be lean, which would result in poor performance.

I would definitely have someone check it out. Whatever you do, get a filter on that thing. Also, checking jetting by way of the plugs on these things is hard to do. You need to do a Plug Chop to get an accurate reading. A plug chop is making a sustained full throttle run, shutting off the motor and pulling the plug out immediately and checking it. Simply riding it around and then pulling it out and looking at it will tell you nothing.

Good luck with it.