big bore kits

[wiley400ex]

I was wandering if the big bore kits were worth the money? Boring it out wouldnt make the engine any less reliable would it? and if i were to get a kit, would just a slip on be fine with it?

[Raptor4439]

I bought mine because i ceased the motor before and since i needed to bore it out I was going to go ahead and bore to a 440ex. The engine will be fine with the bore if you keep up the maintainance. its better to get the whole exhaust system because your stock headers constrict the air flow, the almost same amount of air is still getting pushed through the headers so a slip on really just makes more noise in my opinion. save up and buy the complete system, its worth it.

i agree with u but actually some pipe manufactures say that the stock head pipe on the 400 is just fine.

[Rider#11]

if you go with a big piston..you may want to consider a stronger rod..the stock ones are weak compared a aftermarket one..that way you wouldnt throw a rod..and yes..the stock head pipe is great..thats what i run with my 450ex..the bike has more torque with the smaller stock headpipe...ive ran and larger one and ive run the stock one..i prefer the stock header