it's been sitting around and i finally got around to installing it (15 minutes)...remove slip-on exhaust first...remove the two nuts, but don't drop it.......put fmf megabomb and exhaust back on...

before..hmf slip-on exhaust, k&n, kdx snorkel, dyno jet kit with dj132...'turd was running well...hmf was a little loud, but manageable...had a lot of decel "popping"...

after...megabomb being the only modification...noticeably lighter than the stock header....i didn't put the heatshield on because i wanted to test it immediately (big mistake)...

1. began to melt my ballistic nylon pants within 4 or 5 miles of riding....very minor and rode spread eagle home..hehe...
2. slightly metallic rasp (think all new pipes do this, but it'll go away)
3. quieter idle...
4. almost same loudness as before with the twist of the throttle...
5. biggest difference...almost no decel "popping"...coming down steep hills fast and engine braking, i get some quieter mini "pops"...
6. better throttle response from throttle release to slow and twisting the throttle...could this be from the decel "popping" being now eliminated?

this was a cold start first start of the day after install, but for some reason youtube doesn't like the video format from my android phone...it just shows the start with choke out and video cuts out right before i pushed in the choke..oh well...

 

as mentioned before, it is noticeably lighter...but, i realize the pipe metals must be significantly thinner to save weight...i think this is why it's soooo hot, but at the same time it cools down much faster...it's already cold to the touch!...

for the life of me, i could not get rid of the decel popping with a/f screw adjustments...the megabomb solved that problem and i didn't even need to re-adjust the a/f screw...not having decel popping at slow downs feels great...not sure if this is worth the $210 price tag on ebay..but, definitely worth the $85 i paid another member...for a new megabomb...

 

Is it a real POP? Or, just a bumbling rumble? I quit trying to stop all the bumbling rumble on my HMF-equipped KLX...I think it's just the 4-stroke off-throttle sound that's normal, not necessarily something to be tuned out.

 

it was a loud POP!....POP!......POP!..before...people on sidewalks would get startled when i'm downshifting and engine braking hard...if i was blasting down a steep downhill while in gear and engine braking..it was like a machine gun....if don't downshift too hard or give a little throttle on the downshift, it would just bubble/rumble...but, going 2nd hard and just release throttle immediately...it would POP!...

after the megabomb....even when i'm downshifting hard, the engine is running smooth during the slow down and engine braking...i took it down a hill to see if i get the machine gun, but i get a quiet/faint popping/rumbling now...

i had the fmf q4 before on the same set-up...i couldn't get rid of the decel popping on the q4 either...q4 was a little quieter...

 

have you adjusted the jetting yet ?

 

jetting seems perfect with thd megabomb...it pulling strong throughout the rpm range...and, also does much better at sudden deceleration and acceleration...leaving the a/f screw as is...about 2.5 out with the dj132 main...

 

Have you desmogged your bike? Typically decel pops are exhaust leaks allowing fresh air in, running rich makes this worst. smog reed valve mimics air leak.

 

didn't desmog yet...but, the megabomb eliminated all POP from decel...the jetting is perfect as of now...

 

Interesting! Makes me wonder if you had an air leak on the Q4. Regardless: glad it's working out for you now!

 

Yeah most likely the previous setup had an exhaust leak.