O.K., so i have got evrything for the body that i want on my KFX, and I think its time for the motor[img]i/expressions/face-icon-small-smile.gif[/img] So I have new tires, and rims, nerf bars, bumper, pipe and filter with jet kit, and will be getting handlebars shortly. Now I want somthing to run with the big boys. i mostly do short STEEP hill climbs, and tight woods, with some road riding to get there, so I still want to be able to outrun a piped raptor. so what should I do for about $250? A high compression piston, and cam? I have also heard of putting the head gasket off of the DRZ onto the Z, and raising the compression to 12.5? would that be just as good as a piston? Any ideas guys?

 

No one has any ideas?

 

I would go with the piston next

 

O.K. would just a stock bore high compression piston do well, or should i go 440? If 440 what is the cheapest kit out there for the Z? also how much am I looking at for someone to do the machine work? Also what bore would .40 be? What about .60, and .80?

 

Personally, I would go with the stock bore. I think big bores effect reliablity. SOME, not alot. I would also throw a set of Hot Cams in while I had it apart. Heck, just as well have the head ported to. I'm pretty sure that combo would make most Raptors look silly. Thats what I plan on doing to mine this winter.

If you have a big bore kit put in, I would go with Sparks Racing. I heard his motors FLY. Curry Brothers here in Nebraska do good work on Z's to. Their Z won the 400cc drags at Genoa. The guy winning all the MX races here also said his motor was built by Curry Brothers.

 

I just did the DRZE gasket, head porting, and the exhaust cam (already had the intake). It really woke the quad up on the bottom end and mid-range. The topend doesn't feel right yet but I think I have some jetting issues to sort out still. I've only taken one short ride on it since I put it back together.

I'm not really sure which of the peices had the biggest impact but as a set they are working amazingly well. I did the port work myself so it was just a parts cost. Gasket was $20 something, exhaust cam was $125, DRZE valve springs $48 for set (just wanted the insurance down the road for dyna), machine work for 5-angle valve job and reassembly $80.

I'm going for the FCR40mm next and a dyna. If it's still not enough I'll look into more compression or a little more displacment. I'm already getting to the point where it's making more power then the suspension can handle (at least and keep me on it).