How bad are the stock 250r silencers for performance?

[6bt]

Hi all,
I have a mostly original and bone stock 86' atc250r. Stock exhaust. It seems the stock pipe on many machines isn't bad, (i.e. cr500's, read some where a guy did pretty well either mx or cross country with a stock piped trx250r).

Silencers are a bit of a different story, at least you shave some pounds off with aftermarket silencer.

Was curious if a performance increase would be seen with a stock pipe and fmf/ generic aftermarket straight through silencer?

It will have a full exhaust eventually, like a Paul Turner high rev. Just don't want to waste money on a FMF/DG.

Sent from my XT1254 using Tapatalk

[ps2fixer]

Not really qualified to answer this (little 2 stroke experence), but I always thought the expansion chamber was the HUGE modifier on how the engine acted (and the porting), and the silencer is just a restriction that makes it quieter, straight pipe (proper length) being ideal. Maybe I'm misinformed though, following this thread to see what others say.

[christph]

You should get more performance out of an aftermarket silencer vs. stock. The silencer acts like a bleed off valve for the expansion chamber, the longer and more restrictive the higher the pressure. An aftermarket silencer will flow more freely than the stock silencer. However, you should be able to remove the inner core of the 86 OEM silencer and get more performance. Unscrew the bolts on either side of the silencer and pull it out. I did this on my 89 TRX 250R and it improve the performance quite a bit.