Ok, I bought a used 2005 Raptor. The bike had an aftermarket GYT-R slip-on exhaust and I am assuming the GYT-R Jet kit. I am looking for a little more power. I want to put the K&N Pro Air intake on it and the GYT-R header pipe. Since I know very little about jetting I have a question. If i add the intake and header pipe would i need a whole new jet kit, or can you adjust the present jet kit?
Also I am looking at a Wiseco High-Comp piston, does anything need to be done with induction when you do this?

 

Okay GYT-R sucks for performance better than stock but not by much. This is what i would do. I wanted a raptor so I looked into it and the parts I would have wanted are the LRD full exhaust system (pipe and silencer) which adds 15 horses (around 48), and a k&n filter with powerlid air box cover, and then i would get better rear tires like holeshots, or razr's on aftermarket rims (stock 2 ply) then I would widen it out like 4in. up front, and 5in. in back maybe more because the '05 is kind of tippy. that should get you started on a more powerful raptor. But that is only what i would do. but if you want to stick with GYT-R that is you choice. And you probably will have to get a different jet kit for the most performance. But your jet kit might work. As for the piston I dont think so, but i am not quite sure.

 

If your not sure if your bike is jetted, just get yourself a DynoJet Jet Kit on ebay and call DynoJet and buy some 155,160,165,170,175 DJ jets. Your gonna need bigger jets than the ones in the kit if your gonna run a pro flo intake without the lid and that wiseco piston. When you order the piston, get a 100.5 (666cc) or 101mm (673cc) bore. If you go with a stock bore piston, 100mm, you migt just need to get the cylinder honed. If you go with a bigger piston (which I would recommend) you will need to get the cylinder bored/honed. Any competent machine shop can do this when you take them the cylinder with the new piston. As far as costs go, your looking at:

Jet Kit: $50
Pro Flo: $75
Piston: $130
Bore/Hone: $40

I wouldnt bother with the GYTR header. I got the FMF powerbomb and didnt notice any HP gains.

 

If you go with a high comp piston, you might consider a better rod too. Some guys are still runnin the stock rod with igh comp pistons, but I have read too many stories of rod failure to use it with anything other then the stock piston. I agree with fastestkid. Get something else for an exhaust. I have the LRD and love it. I haven't heard too many good things about the GYT-R, but I have also never used it myself so my opinion is based on other people's opinion. And I could be wrong on this, but I odn't think you can just buy the head pipe. You either buy a slip on, or the whole exhaust. Someone correct me if I am wrong. If you don't know your jetting, like cali said, do it yourself. Get the pro flow K&N, a DJ jetkit, an exhaust of your choice and get to work.

-Brandon

 

get the high comp piston, 11:1, and stay with a small bore and dont worry about your rod.
while your in the motor you might at well port the head and change the cams.

also dump the gyt-r exhaust in the trash, and get a sparks, ct, hmf, lte, yoshi exhaust.