Just done YZ timing

and I'm now sure that i have to get a pipe. still have standard wr400 exhaust

The power has sure changed and it seems to rev out much quicker but feels a little stifled up in the top end. I think it needs to breath a little better

to of all of you who have done this, did you change your jetting?

what sort of pipe do you have?

The best bang for your buck option is a YZ pipe and needle. Full aftermarket system and JD kit would obviously be better, for much morer $$$$$.

I have an FMF header on my WR 400 and had an FMF megamax can on it. I went back to the stock can for noise reasons and I lost a bit of top end(that I really didn't need) and it was a lot quieter. I didn't notice any loss in bottom, if anything I think I gained some. If you ride tight stuff you will be ok with the stock can.

Mine's YZ timed with a full Yosh system. Also I have the air box lid removed. My buddy has an 03' WR, we switch back and forth often. He usually just shakes his head when he gets off my bike, mumbling something like " that bike scares the sh*t out of me" :)

Blue, I'm assuming you have a euro WR with the smaller exhaust. The stock U.S. pipe is a goodie, and yes the YZ pipe is also a good option for you..

not sure what version it is but here's a picture of the pipe.


it appears to have spotwelds in it right down 3 sides of it and i assume they hold what baffles etc are inside. i did consider getting a mate who is very good with mig and grinder to look inside to see if there was any tricks we could do,has anyone opened one up ? that little inch hole just doesn't seem enough, especially when you see most aftermarket pipes.

am currently looking at Australian made Staintune pipe here is link.


still not sure but

thanks everyone for your input.

That pipe is different from the US models, looks exactly like the stock pipe that came with my Canadian model - although I've never ridden my bike with it. I should give it a try sometime - the FMF PCIV I have is way too loud.

I don't know of anyone who has tried to modify it, but I saw a similar thread a week or two ago with an '05 pipe, I think he was an Aussie too. Do a search for that and see what you think.

yeah thanks for that. I think the 05 model actually has rivets you can simply drill out and then do your mods from there but as you see this is sealed and may require some angle grinder surgery. the staintune looks good though.

True, the '05 comes apart with rivets, but if you have got access to the tools to cut the stock one apart and weld it back together, it could be a fun project. Worse case scenario is that you ruin the stocker and buy that sweet looking Staintune anyway. Losing that high placed weight wouldn't hurt either.

That pipe is different from the US models, looks exactly like the stock pipe that came with my Canadian model -

Yeah, this is the canadian model :D This thing is heavy as hell and way too much corked up. I would say the stock YZ pipe is a good deal. I've compared it to the FMF PCIV and I'd say the PCIV is much more noisy :) and I'm not sure any better than the YZ pipe... The PC4 sound is great though :D

I still have to try the quiet insert on that PC4 and see how it goes. I know of many TT members who think it's the way to fly... I'll see.

Oh and by the way, my bike is YZ timed with a WR needle and I do seem to have a little bug that might come from the needle according to JD so I might try the YZ needle (did not even know the needle from a YZ was different until Hamish's post). :)

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