HMF full exhaust

[cletusEX]

For any of you guys running the full HMF exhaust on a 400ex does the header come closer to the oil tank before it bends to go back to the silencer? Thanks

[FF1O5]

a little bit,you dont have to take the oil cooler off though.you will have to wrap your clutch cable in heat tape because it touches the new header and will melt it.

[the yazer]

do you like your hmf pipe i was thinking about picking one up

yes my chitty megamax 2 fell off (well almost)

[240GNCC400]

HMF is definately the way to go. theres enough clearance between the pipe and the oil cooler. like FF said you gotta do something with the clutch cable or you'll fry it.

[cletusEX]

Yeah I definitly like the HMF pipe but I don;t know if it will fit. I have an Arens frame and the motor sits closer to the oil tank than stock. My stock headpipe is already pretty close to the oil tank and I don't know if it will fit. On a Arens frame the two down tubes come straight down to the bottom of the frame where as on a stock frame the tubes come at an angle to the motor. On a stock frame the oil tank is mounted to the tubes where as on a Arens frame brackets are welded off the tubes. I might be able to move the mounts back a little bit in order to clear the header but i don't know if I wanna go through all that trouble. I know a full system will wake up my motor but I don't know if it's too much work. Thanks for the replies.

[3x440ex]

You might want to look into that as far as the full system waking up your motor......I herd on the 416's the full system doesn't do much but add a little HP up top. It only helps on the 426, 440's.

I'm not a mechanic or engine builder so I don't know, that's just what i herd.

[cletusEX]

Originally posted by 3x440ex
You might want to look into that as far as the full system waking up your motor......I herd on the 416's the full system doesn't do much but add a little HP up top. It only helps on the 426, 440's.

I'm not a mechanic or engine builder so I don't know, that's just what i herd.

Yeah I've heard that also. It all depends who you talk to some say it makes a huge difference others say it doesn't really matter. I have to get something new cause my shorty t-4 is too loud for GNCC racing. I figured if I was getting a new exhaust I might as well get the full system, but might just get another slip-on and save some money. Do you run a full system? Did the FCR make a difference?

[3x440ex]

i just run the slip on with my 416....the FCR did help but i'm still playing with the jetting. Seat of the pants dyno says about an extra 3 HP so far but that may change once i get it dialed in.

[crashinmatt]

Originally posted by 3x440ex
You might want to look into that as far as the full system waking up your motor......I herd on the 416's the full system doesn't do much but add a little HP up top. It only helps on the 426, 440's.

I'm not a mechanic or engine builder so I don't know, that's just what i herd.

What I have been told and seems to be true, the full systems will wake any motor, that has been worked over. By that I mean, for the full system to benefit, you would wanna also look into a larger carb and porting your head. The increase in flow out of the motor(usually meaning more power), is truely increased with an increase of flow into the motor. But, then another thing to look into, is how the motor is built and where you want the power to come from. But I run both a HMF full system and a FCR carb, and other than that i have a mildly ported head, and a cam with a 426, and i can keep up and sometimes holeshot the new 450s. Also, like the others have said the clutch cable needs to be wrapped.

[Pappy]

cletus your option is easy.....

an aftermarket headpipe will hit the oil tank:(

[cletusEX]

Originally posted by Pappy
cletus your option is easy.....

an aftermarket headpipe will hit the oil tank:(

Yeah that's pretty much the conclusion I've come too also. I think I'll just get a HMF slip-on. By the way are you guys gonna be at Tomahawk anytime this weekend? I think I'm gonna head up on Sat for practice.

[Pappy]

i doubt it:( i have all kinds of family coming saturday for some damn cook out thing:( but if i get the quad out for a ride on my track....i might be steered towards that direction:devil:


we have a race sunday near morgantown so i might be wrenching

[cletusEX]

Originally posted by Pappy
i doubt it:( i have all kinds of family coming saturday for some damn cook out thing:( but if i get the quad out for a ride on my track....i might be steered towards that direction:devil:


we have a race sunday near morgantown so i might be wrenching

That's cool. Good luck on Sunday.

[wvspeedfreak]

I was thinking about heading to Tomahawk Saturday but I am not exactly sure how to get there(first timer).Could someone give me directions from I-81?

[Pappy]

81 north to exit 16W (route 9 west towards Berkeley Springs)

take route 9 and make a left on route 7

route 7 about 4 miles, make a left on Tomahawk Run rd and the track is about 2 miles in on the right

[wvspeedfreak]

Dang that was a fast response.Thanks Pappy.

[TORO1968]

Can't you see that he never leaves this place? ;) j/p

[cletusEX]

Originally posted by wvspeedfreak
Dang that was a fast response.Thanks Pappy.

Come on out. I should be there. Yellow 400ex with a couple of 450R's and maybe a YFZ.

[wvspeedfreak]

I am planning on coming out Saturday but mainly just to check it out.I won't be bringing the bike due to time restraints this weekend.What time are you going to be there?

[3x440ex]

How far is Tomahawk from Fredericksburg VA?......i might come down if it's not too far.

[pitbull43910]

use a 250x clutch cable it mounts the same its a lot longer and last longer than using heat tape. no the head pipe does not hit the stock oil tank