ya stay away from the big headr pipes unless you have done a piston and cam. my dad has an 01 xr650l and mine is 05 xr650l. we are both jetted(mine 160 main dyno jet kit) and he has an white bros e1 series silencer and i use an e2 series. but he has a white bros headr pipe and mine is stock hheadr pipe. mine runs away from his, especially on the bottom. take it for what its worth. later!

single best mod that isnt free ($0-$10).....PIPE

single best mod that isnt free ($0-$10).....PIPE

Your wrong.......a hotcam improved my power way more than ANY pipe.

HotCam comes later... You would NEVER do a CAM first without first piping and airboxing... More valve into a plugged up exhaust would be nuts...

Your wrong.......a hotcam improved my power way more than ANY pipe.

like bolt said, pipe first!!!! cam is stupid without pipe......SINGLE BEST MOD!!!!!!! so if u could only do one, what would it be? PIPE!!!!

Single best mod is carb for sure.

I'll chime in again. There is no single best mod unless you call removing snorkel, foam air filter, rejetting, and opening up (or aftermarket) exhaust. It all works together. Who cares if you just bolt on a new pipe if you can't suck more air through the front end of the circuit. Even if you are sucking more air and blowing it out the back without more fuel to mix you just lean it out more than an already bad stock condition. Heck take off the smog at the same time, you have to mess with hoses anyway for the carb mod.

Sounds like you know what you're doing anyway, it's fun for the rest of us to all argue the finer points of blinganizing.

I've never been a big fan of the cam mod but certainly have heard a lot of good results. It just bothers me to think of changing the "engineering". It goes pleanty fast with the less expensive mods in place (if you do them all)

you are absolutely right. you must do jets, snorkel, emissions removal, uni filter, and pipe/silencer at same time to get the correct results with no problems! :thumbsup:


I think the advantages of the aftermarket exhaust are somewhat overstated here. I have the standard uncorking plus the Wiseco high compression piston, and have tried many combinations with stock exhaust, a DG megaphone/disk muffler, and a Big Gun headpipe and muffler in my arsenal. The Big Gun muffler has a slight advantage on top end over others, but is rediculously loud (but some folks like that). Otherwise, I was pretty impressed by the Big Gun header, although if I remember right part of the tubes is actually smaller than stock. The stock muffler with the tip removed runs 99% as well as the aftermarket mufflers from my butt dyno, although it's heavy and sounds very goofy. The stock muffler with the stock tip intact but the center cross piece removed has excellent torque, decent mid and top, and is great for not attracting unwanted attention.

Keep in mind that many aftermarket cams get some or all of their power from increased duration. So if the exhaust pulse is longer, the exhast has more time to exit and doesn't necesarilly have to be larger to compensate.

I have to agree with Motometal. I have never experienced much HP increase with aftermarket pipes. Sometimes I wonder if people believe that because it is louder, it has to be faster. I found out on dyno tests with my other bikes that this is not the case. Motometal what do you mean by "center cross piece"? Do you mean that little 1/8 rod that is welded across the opening of the pipe?

I guess to be most accurate I would say if you can UNCORK the bike thats the critical issue... That is not always possible with a stock pipe... Newer bikes seem to make it easier... My XR600R had a 30 pound welded exhaust pipe... So YES aftermarket was mandatory to achieve breathing..

My buddy with a TRX450R just needed to install the HRC plug... So I say the power comes in unplugging the exhaust... but FMF, Big Gun, WB or stock pipe if it's built right and unplugged will all do !

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