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02 ktm 125sx exhaust help!

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whats up?? Im looking for some good exhaust advice........I recently picked up an 02 ktm 125sx....i have it running good, geared the way i like...almost perfect...starts first kick each and every time...idles and revs mint.....it came with a pro circuit pipe, and what looks like a stock silencer...this set up feels pretty good, but then again i have nothing to compare it too...the pipe has some good size dents and iv noticed a pin hole leak, and the silencer looks like it too has seen better days...so naturally i want to replace them....heres where id like the advice....although its an sx, i mostly ride trails/enduro,lots of mud and good stuff.... but some mx too.....im looking for some feed back on exhaust combo options, preverably something thats good all around, and i can bolt on and go...i have mt jetting mint and would rather not have to mess with that....anyways...what ever input...good or bad would be great...thanks

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I agree with "Doudle S.O.B." (lol)  The FMF Fatty is a great pipe, with noticeable performance gains throughout the entire power band. It can be used with either the stock silencer (non spark arrested) or with any other silencer with stock dimensions... The Turbine Core 2 (spark arrested and U.S Forrest Service approved) is probably the best compliment to this pipe though, they really work well together. Great all around combo for a "woods" bike.  

 

All that said, FMF used to make an SST pipe for the 02 with compatable Shorty (non-S.A.) and TurbineCore2 (S.A.) silencers. The SST had a longer stinger with a power chamber at the end of the cone so stock silencers would not work with them. The two afore mentioned silencers were the only 2 over the counter silencers that would work with it (unless you drastically modified a stock dimension silencer). These pipes were absolutely awesome and gave the top end and mid range a real kick in the ass without compromising ANYTHING on the bottom end... Unfortunately, they have been discontinued for the 02 KTM 125sx for quite a few years now, but you might find one on ebay every once in a while or as clearance stock from a parts house. Good thing to keep an eye out for and snatch it up if you ever come across one. If you read up on some of the old reviews in the Mx magazines from the early to mid 2000s, you can get a good idea of what the pipe system was all about. Really sad that they don't make them any more. 

 

Also, keep in mind, that the engine is nothing more than an air pump... It pumps air in, and pumps air out... After you make up your mind on an exhaust system, it is also a keen idea to "free up" the front side of the pump so to speak. Consider an air filter that flows a little more freely, and upgrading your reeds to a lighter reed or a VForce 3 reed block. These mods will help your new exhaust realize its full potential and allow your engine to perform without gasping for air, albeit you WILL have to do some minor jetting changes to richen things up a bit regardless of which mods you do... MORE AIR FLOW (front, back or both) means MORE FUEL... PERIOD!!!! This holds especially true with 2 strokes as you run the risk of burning things up if you don't.  Consult the data sheets that come with the parts to see what is recommended and go from there. :)

 

Hope this helps.

Edited by Runt424
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I had an 03 125sx that came with a PC platinum and r-304 shorty. Excellent set up, I liked it enough that I put the same set up on my 150, worth every penny. Combined with 13/50 gearing it added quite a bit of low and midrange without sacrificing top end. I do run an FMF turbinecore sparky with it when I'm in the woods. KTM's jetting charts make it easy to re-jet and are pretty accurate, you will likely have to tweak your jetting with any aftermarket pipe.

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