Hey everyone!

I haven't been around much, but am going to start coming around a lot more as I have a lot of things to go through on the bike this winter.

Had a topic on here, a few years ago it seems, about my exhaust leaking. I replaced the O rings inside, cleaned it up nice, and three rides later it was leaking again. For what those little rubber rings cost me I decided to just leave them alone. Now after 2 years, the stock pipe has got a crack in it that needs to be weld and the O rings too. Now with that being said, I have also been thinking about adding a different pipe for a while and have decided it is time to pipe the 250.

I have a few questions first tho.

Will an aftermarket pipe make any difference in my O ring exhaust leak? Do they use somthing similar to the stock set up to seal or is it totally different?

What would be the best brand for me to get? (I would guess it is just like anything else and it really makes no difference what brand I buy.) I am not planning on racing it, just some trail riding, gravel pits, sand dunes, and occassionally run it on the track for fun.

I also really like just getting on the bike and riding it, I see that some pipes require some looking after so I would like to stay away from those as I don't really wanna spend a bunch of time on cleaning it up nice and have the pipe rust out or something.

Also what kind of silencer should I run? Shorty? The longer style one?

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Best combination i have found so far for all around performance on the yz's is a 06+ STOCK pipe with a standard length R304 silencer. Provides a very linear powerband and combined with the standard R304 gives you even more top end over rev.

other wise i'd say Pro Circuit Platinum for a pipe, however it is a more mid range pipe and takes away too much in the bottom end for my liking.

unless you wanna fork out some mucho $$$ on a DEP Exhaust system (have to import in from Great Britain lol

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See I like bottom and mid range. Top end to me really means nothing unless your drag racing or else hill climbing or like top speed runs.

I personally am looking for something that pulls some G's out of the hole. if stock is my best be then I guess getting the stocker welded and the adding the R304.

Money to me is getting to be less and less of value as I get older. My reasoning is cuz I can't take it with me when I am dead and I can't take my toys with me either, but I can take the memories I make on them.

I spent some time looking at pro circuit's set ups today prior to your responce MX, I will continue to look for atleast a few more days.

Hopefully I sturred the pot here at DF enough to get guys/gals to come up with some of their own topics.

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Keep in mind i said a stock 06+ Pipe... it was reworked from the 02-05 pipe ;) more bottom end and smoother power delivery. if you want a pipe "similar" to the 06+ spread the FMF Factory Fatty is what you want to look at.

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Hey MX, whats your opinion on Bills Pipes for a yz125?

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Oh ok, well that makes sense. I will have to look into the FMF.

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Im no 2 stroke pipe expert but make sure you realize, at least from my experience (85's and 125's) you dont necisarily add more power, you just move the power you have. So if you get a bottom end pipe that is most likely goin to take a bit from your top end. Again this is just what I have experienced.

I typically like to get a bottom end set up. I think of it this way, when is the last time I had my bike completley toped out that I couldnt shift to another gear. 85's yes this has happened, 125/250F rarely, 250/450 i believe their are very few people that have those bikes completley topped out and didnt have another gear to shift to. (keep in mind im talking about riding on a track). This is why I like to get bottom end pipes, your always gonna have another gear to shift to if your gonna need more speed, and when you do shift you will have that much more immediate bottom/mid power.

Again this is just what I prefer, but something for you to consider.

For what pipe to get I think mx is alot more educated in that area than me. I put tried procircuit and fmf on my kawi's (85s and 125s) and would prefer the pro circuit over fmf any day. On my 125 yamaha i tried both and would prefer the fmf over the procircuit.

As far not wanting a pipe you have to really look after and keep up on. Spraying so wd40 on it will help. I wash my bike everytime I get done riding, and spray my pipe, parts of the frame (especially under where the foot pegs connect) bottom of the engine down with wd40 and has worked very well for me.

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Piping a 125 IMO is a waste of time unless done for MX application were you are always on the gas and on the pipe



You are correct in the shifting of power in the RPM range in a sense. If you look at a tuned pipe dyno, you will see a general increase in HP in most ranges, however you get that seat of the pants feeling that it is just shifted since there is usually a dramatic increase in one specific area or what the pipe was designed for. not so noticeable on sleds since the CVT does a pretty good job of smoothing that out and keeping it linear.

so I encourage you to look at a dyno chart for the FMF Factory Fatty vs the Pro Circuit Platinum on the same bike. you'll be surprised what you find for results as the pipes are marketed for the same purpose, but built completely different.

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I will look what we have for a pipe set up on my 125. Its FMF but im not sure what model, we have pipe, silencer, and vforce reeds and that bike is fast as ****! Ill check the gearing also.

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I am currently looking for dyno sheets of both pipes on the same bike to get an idea of what to get for a pipe set up.

So what your saying MX is that if a sled had a tranny like a bike you would feel more of the power increase of the pipe similar to the way a bike reacts when an aftermarket pipe is added?

And for my application, would the FMF Factory Fatty and Pro Circuit R304 would as close to 06+ stock pipe and R304, or should I not be mixing and matching with two different companies? I know with some sled pipes it is bad news to mix and match.

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Now you're getting into a whole separate monster when adding in a Tranny vs CVT. The CVT is good in that it is load sensative so it is always adjusting to provide good efficient power to the track. Tranny just puts power down, no adjusting on the fly, all operator controlled.

The FMF Powercore is just as good as the R304, I just like the 304's raspier sound personally lol

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Oh I gotcha so either or will work pretty much the same.

Ya I understand the CVT a lot better then a tranny, but I am still learning about both.

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