Pipes

[00_yamaha_man_125]

because have you been to St.Ignace before, it is trail riding but i am going to be going to the track with my friends next year just for fun

[rm250dude]

yeah see denny even agrees with me pro circuit is better

[rm250dude]

yeah ive been to st ignace but im not much of a track rider im all for the trails though

[00_yamaha_man_125]

thats what i mainly ride

[rm250dude]

sweet maybe ill go ridin with ya sometime

[00_yamaha_man_125]

yeah just tell me when you come up

[MX86]

pro circuit makes the overall best pipe for a dirtbike IMO. they make a pipe for specific years to boost overall performance...

but your not going to gain much from adding the pro cicuit from the fmf..

[00_yamaha_man_125]

so i might as well just leave the fmf on it. instead of buying a new pipe

[nsewyz125]

The pro-circuit tends to have a smoother power transition and more top-end and over-rev. If you are trying to find more out of your YZ, look more towards reedcage, porting, or other minor mods. Easier to tune the engine to the pipe than the pipe to the engine. A stock yz125 makes about 34hp. By keeping the stock bore/stroke, I am getting about 48.5 out of my best national level motors, so theres plenty there to be had. A stroker kit will net even more, and a big bore will only help a little bit on these motors. When you go big-bore, you affect the port timing tremendously and not in a good way.

[flotek]

Originally Posted by nsewyz125

The pro-circuit tends to have a smoother power transition and more top-end and over-rev. If you are trying to find more out of your YZ, look more towards reedcage, porting, or other minor mods. Easier to tune the engine to the pipe than the pipe to the engine. A stock yz125 makes about 34hp. By keeping the stock bore/stroke, I am getting about 48.5 out of my best national level motors, so theres plenty there to be had. A stroker kit will net even more, and a big bore will only help a little bit on these motors. When you go big-bore, you affect the port timing tremendously and not in a good way.

48.5 hp o n a gas 125 ? those must be crank hp numbers ,not strapped down to a dynojet with rollers for a true rear wheel rating the na agian a shifter cart weighs pracitcvly nothing and with tiny wheels and axle has hardly any load