I have been thinking about getting a new exhaust system for my klx250s for some time. What do you think will get me the most horsepower gains? Should i go slip-on or a full system like muzzy complete or big gun complete system? I know i will have to rejet the carb and what would be the best setting for the pipe you think is best?

 

You'll get more by opening up the airbox at the same time. Unless you use it in deep water crossings, you can just take the top off the airbox.

Jets, I'd just buy a Dynojet Jet kit

 

Full Exhaust
Jet Kit
Airbox mods are MUST HAVES !!!!

The bike is completely different after you do these. It is also best to do these all at the same time like mentioned above.

All the exhausts are basically the same. Meaning just straight thru designs ( basically a glass pack ), it is just the size of the casings that differ. Some are more quiet, some are louder.

Many will argue that a header doesn't do anything, mine runs better with a header so thats my two cents.

 

I did the fmf q4 and power bomb and the dynojet stage 2 and uni filter with snorkel removed at the same time and can honestly say it was a major improvement. In stock form the bike need quite at bit of time to warm up and had a nasty flat spot just off of idle after the mod all disappeared and the bike runs great.

 

I recently did almost the same mods (but K&N filter and put in the big snorkel) and agree 100%. Totally different bike!

MUCH smoother, especially at low and high rpms, no hesitation anymore.

Starts a lot easier and warms up faster. Very little popping on deceleration.

Sounds great, not much louder at low rpm and sounds really good up high.

And like another poster said, it also seems to shift easier. Don't know the connection there, better flow, less restriction?

Love it!

Go Green!

 

I will agree with everyone above on how much better the bike runs after the jet kit install.

Regarding which is the "best setting" you should probably contact the company where you bought the exhaust from and ask them.

I have a Two Brothers exhaust and went with the jet kit settings they told me gave them "good results."

So far I'm VERY pleased with everything.



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Hey all,
I'm new to the forum but have been reading it religiously ever since I got my KLX about 2 months ago. I can tell it definitely needs opened up so I'm going to be going with a full exhaust and the Dynojet kit. My question is does this effect the gas mileage much. I am mostly on the pavement commuting back and forth from work. Right now I am getting just over 60 miles per gallon. Anyone know there mileage after these mods??

Also this might be a dumb question but I see alot of people that have modified or removed their snorkle... what exactly is the snorkle? and should I mod it? I already removed the air box lid. I'll prob dig in their a little deaper tonight and see if I can find this snorkle ha

 

Some of us, but not all, have noticed a decrease in mileage. A few claim slightly better mileage.

The snorkel is the rubber "L" shaped piece in the air box lid. It can be pulled from the lid, and/or replaced with a larger, higher-flowing snorkel. It's a good idea to have when you ride through deep water. My lid is off, and I've filled up the Al Gore approved plastic catcher attached to the bottom of the air box via hose (the damn thing hasn't fallen off yet!) on some rides through water crossings. I need to get the larger snorkel.

 

Some of us, but not all, have noticed a decrease in mileage. A few claim slightly better mileage. My mileage is running in the mid-40s, but I have geared way down also (13/49) and don't run above 45 mph very often so that probably has a lot to do with it. The mileage can suffer if you jet too rich, or maybe if you start having too much fun with the right hand. I first jetted too rich, and leaning it back has appeared to help (had mileage in the low to mid 30's for a while). Many of my rides have been difficult and slow with average speeds much less than 10 mph.

The snorkel is the rubber "L" shaped piece in the air box lid. It can be pulled from the lid, and/or replaced with a larger, higher-flowing snorkel. It's a good idea to have when you ride through deep water. My lid is off, and I've filled up the Al Gore approved plastic catcher attached to the bottom of the air box via hose (the damn thing hasn't fallen off yet!) on some rides through water crossings. I need to get the larger snorkel.

 

Thanks for the info, with my gearing (15-42) I think the mileage will be just fine. Most of my riding is 50+mph. Every once in awhile I'll jump off the road if i see a good hill to climb or some small dirt hills to test my suspension! I don't think the farmers in my area like me too much