piped yfz getting beat by a stock ltz 400?wtf

[yfzrider310]

my friends have races and his yfz get whooped by the ltz and the raptor 660. is the problem that its not jetted right or what. The yfz has a gytr pipe and the other two are all stock. The numbers just dont add up. If someone could explain to me why this is happening please do.

[400exfan19]

ummmm, that isnt right, he should be able to tell if the jetting is off, or he just cant ride at all if he gets beat by a stock 400....

[07yfz88trx]

ya im guessing hes horrible at riding because it should be the other way around i kill 400's and 660's with pipe paddles intake and more stuff on my stock yfz all the time

[yfzrider310]

well hes not that bad of a rider because hes been riding manual since he was 6 so thats not it. but it does backfire and get really hot really fast. I think it might be running to rich but correct me if im wrong. Im getting my yfz today so well se if il beat his yfz cause mine is stock.

[400exrider99]

if it gets really hot fast he is running too lean

[miles Machine]

makes sense to me that its getting beat, after all it is a yamaha

[cjkranz]

Just remember, Lean is Mean (for a little while and then boom!)

[yfzrider310]

haha

[yfzrider45]

i have a full duncan exh. and fatboy 4 jets on my yfz and it runs good.....maybe clean the carb every couple weeks, i do that and it runs perf.

[Hondamaster5505]

Originally posted by miles Machine
makes sense to me that its getting beat, after all it is a yamaha
What are you talking about?!?
Yamaha's one of the best brands out there..
Look what Honda did to their new line of Sport ATV's, its a disaster!
I have a Honda now, but thats because they are my second favorite brand next to Yamaha, and i just happened to get a good deal on it.

And about the YFZ, it sounds like hes running way too lean, do you know if he jetted it at all?

My dads buddy has a 07 YFZ with an HMF pipe and cam mod, and my piped 400ex doesnt stand a chance...

[YFZ450Ridr]

like everyone else said, jetting must be off, possibly his tires are bald, or he is geared insanely low. my yfz Smokes my dads piped, intake, and jetted z400. somthings up!

[yfzrider310]

hes got new holeshots on the yfz the z has got mudzilla but idk if that would make that big of difference?? other wise they both have stock gearing to

[TRXRIDER4567]

obviously a piped andjetted 400 ex wouldnt stand a chance againts even a stock yfz.

[pro-rider46]

sounds like its jetting is off, or he has no nuts. but if you guys know how to rejet them carbs, put a bigger main jet, adjust his needle a clip. and see if it runs better, do you know what his jetting is to begin with. what year bike is it, my friends yfz has a 178 mj i think, and gytr needle on the 3rd notch, and it it runs real strong,