I just picked up a 2007 KFX 50 atv for my boys for Christmas. As far as I could see, there was very few hours on the machine and it is in good condition. I don't think any restrictor mods have been done and probably will not do them until I see how my 6 year old does with the tav. The only thing that I found is that you have to get the RPM's up a little higher than expected before the transmission finally engages. If I turn the throttle limiter screw in to where I want to start out, the transmission will not engage. Also, when it does finally engages, it jumps forward rather than a smooth roll on response. Does this indicate a problem with the transmission or the drive belt or is there something that needs to be adjusted? How soon should the transmission start to take off?

 

im not sure you will be able to find a lighter set of springs but it would help the clutch enguage faster,

 

Well you are probably right. I took the cover off to check the belt and it looks new and measured within spec. I cleaned and lubricated the clutch shaft so it could move a little easier. It still does not engage early enough so that may just be the way it is intended. There should be something you could do to make it work at lower rpm so the kids can just get the feel of the machine. I thought about test riding a new one at the dealer just for comparison.

 

I just purchased a 2009 kfx 50. I felt that it had to rev too high before it could pull off. I watch other ones on youtube and it didn't seem like they had that problem. Could it be that something is slipping? How can you fix this?

 

Welcome to the forums.
Maybe service the clutchs and see if something is wrong.