my friend jsut bought a yfz450 and is planning on modding it soon... i raced him with my 400ex and i ran right next to him up until 5th gear when he slowly pulled away. my question is, what can i do to run wiht him when he starts modding it? money is a slight issue but i can spend like a grand on goods.... keep in mind i cant have a loud @ss quad due to where i ride.. thanks

 

Those YFZs are pretty fast!
I think the only chance you have would be to go with a 440 high compression kit, pipe, aftermarket air filter, and (possibly a timing advance?)

 

well look at my sig... i got quite a few mods.... i think next is boring?

 

Sorry, didn't look at your sig. LOL![img]i/expressions/face-icon-small-smile.gif[/img]

Yes, I would say the next thing to do would be to go with the 440 kit, and possibly have some porting done, with a high comp piston, but be aware you will have to go with race gas if your compression goes up too much!


Or............

You could sell the 400 and get one of the YFZs yourself.[img]i/expressions/face-icon-small-wink.gif[/img]

 

who do you think i should go with for a 440 bore? and about how muhc $ will a bore be and what are the gains? thanks again

 

I'd give FST (four stroke tech) a call at 814-842-9159. I know they also make a 500 big bore kit for the 400ex also.

 

I believe you can get the kit from several of the major manufacturers
Looks like Mickey Dunlap does them too from the last post here.

Not sure if LRD does them or not?

The kits (I believe) run 400 to 500 dollar range give or take possible more, depending on what else you get done.[img]i/expressions/face-icon-small-wink.gif[/img]