pipe shoot-out

[Big Orange]

This is exactly what I'm doing to my '08 450 xc. MaX power bored and replated the cylinder to 540, baldwin head job, 806 camshaft, Ti megabomb exhaust and Ranchero bored the carb to 41.5 mm. Man is this thing gonna run! I'll keep ya'll posted.

[Deadman]

Let us know how that Megabomb works out. I have one for my Polaris 525, but haven't installed it yet.

[frdbronco8]

The head is on its way to baldwin and the motor is on my mechanics bench ready for the 540 and I cant wait! Whats the going rate to bore the carb 41mm? My local guy asks 175 and I was wondering how that compared since I dont have to pay shipping.

[Deadman]

$125 shipped for a 41, 41.5, or 42mm bore.

[orangesuperbeast]

Maybe he just doesn't know what he is talking about. Quads are new to KTM-only shops and he might be a two-wheel guy.

I have the 450xc with the factory 540 bb, both times at the dunes i pulled wins on modified 450's. first time out i rode factory rzrs had to do rolling starts and smoked two modified hondas hands down. Second time out was running down a modified raptor 700, never got a good start swing arm was extended on raptor and he'd get me on the take off. I was runnig 22" 10 paddle side winders and would stand up in 1st,2nd, and 3rd. Buy the 450 and get the 540 kit I got it cheaper than the 525.

[JDU450XC]

from what I have heard the hmf system fixes the decel poping. Just ordered mine today. And a stock 450 beats a stock raptor 700 so I can see where a 450 could beat the 525. everyone says no so I'll take your words for it since mine wont be stock for long so i'll prob never get to do that race myself.

2 Points to make:
- I had a Raptor with a big 3 Mod and about 55HP+ to the wheels and it was a bear to keep the front end on the ground when going through the woods which got me in trouble a few times. So through the woods, depending on your weight and how well you ride, the 450 COULD be faster through the woods.
-Secondly, I bought a 450 because I wanted to go to a few GNCC races and see how I would fair as an amateur and I didn't want to ride in the open class, I wanted to run with the 450's.

I would say in a straight line, unless the 450 just spools up that much faster then the 525, you will NOT beat it on the 450. Through the woods, depending on the rider, they could be neck and neck through the trails. And the person who said their yfz450 quad with a pipe beat a 525 in a drag race................obviously the person on the 525 was not a good rider because that would not happen!

[Deadman]

I dyno'd my FMF Megabomb on my Polaris outlaw 525, and it LOST 1/2 HP, and 1/2 Torque all the way across the board. I sold it, and put the stock header back on!
The only advantage to the Megabomb was that it reduced noise a little bit. I was afraid the Titanium might crack too.

[colemanktm]

I dyno'd my FMF Megabomb on my Polaris outlaw 525, and it LOST 1/2 HP, and 1/2 Torque all the way across the board. I sold it, and put the stock header back on!
The only advantage to the Megabomb was that it reduced noise a little bit. I was afraid the Titanium might crack too.

if you lost power on the dyno why would fmf take the time and money to build and dyno a pipe just to lose power??? is it your dyno?

[rumlesj1]

in my opinion they didnt do too much testing on this header. because nobody seems to like it.

if you lost power on the dyno why would fmf take the time and money to build and dyno a pipe just to lose power??? is it your dyno?

[Deadman]

I don't know, but the simple facts are that it lost power all the way across the board on the Dyno. It was about 1/2 HP all the way across, torque also.

[sandshredder]

" I was afraid the Titanium might crack too. "
a friend of mine put a used mega bomb on his kids yfz. it lasted about 8 months. the thing backfired a few times and split the "bomb" section wide open.

[Big Orange]

Never been a FMF cheerleader, but never seen a FMF pipe failure that didn't have some kind of owner induced injury. For example the YFZ in the post above, In a proper state of tune the machine doesn't backfire, and therefore doesn't blow the pipe open.

[rumlesj1]

i actually seen one on a yzf dirt bike that blew apart, but like u said it was prolly human error. bad jetting that could have caused a backfire to blow up the pipe.

[crslt01]

My outlaw lost over 1/2 HP with the megabomb

[alanmhewitt]

Hi Team,.. I have a question which relates to tuning my 540 XC I have installed a FCI Inducation, SAMCO Hoses.. No Thermostat, MINO High Flow Water Pump, Keihin FCR-MX 41 with Power Bowl 2,

live in Dubai.. Summer Temp Early Morning 40c to Mid Day 55c, Winter early Morning 8c to Mid Day 20c and the riding enviroment is desert riding

Heat is a big problem.. The Exhaust is a very large heat source, has anybody looked at thermal barriers for the Intake, Carb, and Fuel system, and any feedback as to what works, and does not!

a) Rapping Heat Tape for the exhaust
b) Carb Heat Shield
c) Engine Heat Scavaging of Hot gas's by the big bore exhaust.. My interest is around FMF Power, or Mega Bomb's
d) Heat Shield for the Fuel tank, Fuel Pipe
e) Blanking the Crank case breather why heat the "intake Air"!

Thanks Alan

[rumlesj1]

fourwerx was making some heat shields from carbon fiber last i looked. also u could use some exhaust rapping.

[rumlesj1]

oh ya also could look into a oil cooler and dual fan setup.

[ibmorjamn]

The dasa actually did a touch better than that. I printed the wrong graph. Ill post the right graph.

Here it is. Mods or ranch please replace the dasa graph with this one. THanks

So the Dasa did +1hp/trq over stock modified Slip on ? The CT didn't help much but I'm guessing the key to all of these was the flow related to the diameter of the opening. I bet the CT was more quite. I am set up right now to put a HMF turn down cap and spark/screen with a straight through baffle on the stock Slip on, might shorten it 4". All I can see that would help the headers is taper and diameter of the tubing. Long primary or shorter primary before the transition. Transition is a focus as well. imho