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.

RE: Drilled out stock vs KLX300 exhaust
 

Here is a couple of photos of one type of insert you can use inside the Quiet Core to lower the decibels even more.



[IMG]local://upfiles/5289/901B663F1C9D4A9E85FC994E9D547516.jpg[/IMG]

RE: Drilled out stock vs KLX300 exhaust
 

...and from a different angle.



[IMG]local://upfiles/5289/84EB8AF389E941DC92059800C5347654.jpg[/IMG]

RE: Drilled out stock vs KLX300 exhaust
 

That looks pretty slick. Did you make it yourself? Any chance I could get the specs and instructions (or talk you into making one for me :D...pay you for T&M)?

RE: Drilled out stock vs KLX300 exhaust
 

Sure thing, I had the local machine shop make it for me for $20 if you're interested - better than putting the stock exhaust back on!

RE: Drilled out stock vs KLX300 exhaust
 

I would be very interested as well! Rather than re-inventing the wheel.................
It would be much easier to have one shop make a few of them.
If this is possible, just let me know.
Heck You could go into business for HMF mods.
Thanks Much!
Don

RE: Drilled out stock vs KLX300 exhaust
 

+1 Yeah, if you don't mind going back to the machine shop, I 'll take one as well.

RE: Drilled out stock vs KLX300 exhaust
 

Okay, I have three orders - anyone else?

RE: Drilled out stock vs KLX300 exhaust
 

http://www.ear-mart.com/images/Three.jpg


:D

RE: Drilled out stock vs KLX300 exhaust
 

Seriously DJ, Fireroad, & KLX I can't believe you guys think the quiet core is loud! [&:]

It's just about perfect and makes the KLX sound like a baby Manx.

I love the way it sounds when it hits 6000 rpm and beyond.

It is in no way loud to bystanders either as they all wave and smile as I ride by. :D

RE: Drilled out stock vs KLX300 exhaust
 

FM, I'm with you - I like the sound of the HMF as is. I also got a laugh on the ear "plugs" (personally I just crank on my iPod) - but if that's what they want I'll get it for them. My friend is happy with the Quiet Core "extension" piece and I'm happy to help out.

"I'd rather have a bottle in front of me than a frontal lobotomy."

RE: Drilled out stock vs KLX300 exhaust
 

YA YA YA...................
I'll still take one. Just let me (us) know the details when you get them.
Thanks
Don

RE: Drilled out stock vs KLX300 exhaust
 

Uncapped 300 exhaust and 10 minutes of riding and my right ear was ringing. In went the earplugs and continued on my way. Made a different endplate for it and its a good bit quieter than full open but sounds kinda funny on decel. Might just go back to my downturn though as I don't care for the exhaust deposits on the rear fender.