Stock Vs FMF Vs Pro Circuit

[Markee757]

I'm curious how these pipes compare to each other in general stock terms. Any info would be greatly appreciated.

[Sandblaster]

So much will depend on the kind of riding that you will be doing.
It will also depend on which FMF and which Pro Circuit pipe..
The stock pipe is actually pretty good for all around riding.
We have a completely stock KX500 running a tad over 100mph on a stock pipe.
The Pro Circuit 1 pipe is the highest HP and great for Supermoto, Desert, or dunes riding.
The FMF Woods Gnarly is a good low speed to midrange pipe and is best suited woods and short MX tracks.

[Markee757]

Awesome.

Personally the bike I'm building would be for 3-4th gear max sand tracks.

Silencers, any experience on what complements the stock pipe?

[Sandblaster]

FMF Power core is great for tracks but it is a bit loud and does not have an arrestor.
The FMF Turbine core is a good choice if a arrestor is required.

[Markee757]

Guess I'll try the Power Core. I Dig that 4 stroke looking pipe Sean is using. Maybe I could make one from a slip on??

[Sandblaster]

Lol... Yeah it is nice.
Yes, you can take a 250f muffler and convert it but you will need to get or roll a kx500 core.
We have been discussing getting some made but it's still in it's very earliest stages...

[Markee757]

So I got the powercore in the mail the other day. Its BIG. Got me thinking if there was a particular length that works better for low to mid while using the stock pipe.

[Sandblaster]

I don't have any specific length info off the top of my head.
Although I did have the length's for the shorty at one time and modded a custom muffler using that length.
If you are going to make your own shorty muffler, let me know and I will get you a length.
The shorter the muffler length the more bottom end.
The longer the muffler the more top end you get.
I have been all over the spectrum with long vs short and did notice a difference... but only a small difference.
Your muffler is a good compromise in length..