Drilled out stock vs KLX300 exhaust
 

Did anyone drill out their stock exhaust (1/2" through both baffels) before switching over to the KLX300 exhaust? I would like to know how the two compare. I have a HMF slip-on right now, love the power and snap, hate the noise. Put the stocker back on and drilled it out. Great sound, not much power gain. Will I notice a big difference with the KLX300 muffler and head pipe vs a drilled out stocker as far as power gain and throttle response?

RE: Drilled out stock vs KLX300 exhaust
 

Yep, you sure will! A friend of mine that I ride with has a KLX300 which he modified, he gave me the muffler and header which I mounted on my bike for about a week before I got the HMF slip-on. As for power, the HMF is better than the stock KLX300 exhaust but sound wise the 300 is quieter. And of course the 300 exhaust is way-way better than the 250 drilled out exhaust.


"If my calculations are correct, when this baby hits eighty eight miles per hour, you're gonna see some serious sh*t." - Doc Brown

RE: Drilled out stock vs KLX300 exhaust
 

I never drilled out a 250S exhaust but would be comfortable sayting the 300 exhaust, sans plug, is a step above the drilled 250S exhaust. I mean, the 300 has a 1.5" outlet ves the 1/2" drill. Plus the 250S has the cat, which prob by itself is not so bad, but who knows how that compromised the internal contruction for it to fit.

RE: Drilled out stock vs KLX300 exhaust
 

[quote]ORIGINAL: klx250s_rider
Yep, you sure will! A friend of mine that I ride with has a KLX300 which he modified, he gave me the muffler and header which I mounted on my bike for about a week before I got the HMF slip-on. As for power, the HMF is better than the stock KLX300 exhaust but sound wise the 300 is quieter. And of course the 300 exhaust is way-way better than the 250 drilled out exhaust.
/quote]

How did your freind modify the KLX300 muffler? I've heard of people making new endcaps to make them quieter, but I haven't heard of anything like drilling them out? I love the hmf power, it's a shame they don't make a second level "quiter core".

RE: Drilled out stock vs KLX300 exhaust
 

He didn't modify the stock pipe but replaced it with a Pro Circuit exhaust - he gave me the stock pipe and muffler. You can also modify the HMF Quiet Core insert to make it quieter.

RE: Drilled out stock vs KLX300 exhaust
 

Really! how?

RE: Drilled out stock vs KLX300 exhaust
 

You can spot weld a thin piece of sheet metal (T-shaped) inside the quiet core (runs the length of the core) which acts as a baffle without too much noticeable powerloss and quiets the bike down by 30-40%.

RE: Drilled out stock vs KLX300 exhaust
 

Mark:
Could you possiblypost a photo or supply a drawing of the quiet core insert mod.I would like to try this and have often thought about what approach to take. Our bikes seems to be set-up indentical, so I hope this will work well.
Thanks
Don

RE: Drilled out stock vs KLX300 exhaust
 

+1 on the pics please

RE: Drilled out stock vs KLX300 exhaust
 

I'll have some photos for you this afternoon.