400ex Exhaust Conversion Started

[thebutelr]

Hey guys I have been throwing the idea around for a few months on modding a 400ex head pipe to fit an aftermarket slip-on for a 400. After a long time of looking at NOS_350x's pictures of his bike with the 400 system I finally decided I would make an attempt at it. Well here it is, I almost have everything cut right and temporarily fitted before I take it off to get it welded in place. Hey, its a start! :beer :w00t: http://i100.photobucket.com/albums/m14/thebutelr/IMG_1614.jpg
http://i100.photobucket.com/albums/m14/thebutelr/IMG_1612.jpg

[oldsking86]

Looks very nice! Hopefully you'll get a bit more power out of it too :beer

[jsimonh]

Looking good so far:naughty: . What brand of slip-on are you gonna use?

[thebutelr]

Looking good so far:naughty: . What brand of slip-on are you gonna use? HMF :w00t: .

[NOS_350X]

Looks like its perty much exactly what i did. Make shure you have the slip on before you weld it all up. That way you know its all going to line up perfectly. you might have to adjust it up or down a bit, at least i had to.

[super90]

HMF is a good choice! I had them on alot of my toys in the past and they sound great. I bet there are alot of aftermarket pipes that almost fit atc's, just noone has the money/time to try them out.

[NOS_350X]

HMF is a good choice! I had them on alot of my toys in the past and they sound great. I bet there are alot of aftermarket pipes that almost fit atc's, just noone has the money/time to try them out.


I have tryed many diffrent ones. There are a bunch that need just minor cutting and welding to fit. the trx400ex one is the easyest for the 350x.

[thebutelr]

Well guys I just won a HMF slip-on on ebay and its in great shape! I should be getting it by tuesday of next week so expect some finished pictures of this project then and a ride report. This will have to do for now! :beer http://i100.photobucket.com/albums/m14/thebutelr/b12e_1.jpg

[super90]

that almost looks like it will bolt up to a 200x?

[jsimonh]

Any updates? I may have to get one of you guys to build me a head pipe one of these days:naughty: .

[thebutelr]

Well guys I am finally finished with my conversion:w00t: ! After a long time of trial and error of cutting the wrong places on the pipe (ooops!) I finally got it mocked up and took it to get welded this morning, got it back and man was I impressed at the work the local machine shop did on it. I was pretty nervous before I tried to bolt it on for the first time thinking that it wouldn't fit right and boy was I wrong, it surprisingly fit very well!! The only thing I have to do now is get one new header stud nut (which to my great luck magically stripped out when I put it back on today :crazy: ), new gaskets for the exhaust ports and one new gasket for the spot where the silencer meets the header. Once this is done my exhaust leaks should be taken care of and it will be off to getting her jetted right! Well I've rambled on enough, here are the pics, enjoy!! :w00t: http://i100.photobucket.com/albums/m14/thebutelr/117_9096.jpg
http://i100.photobucket.com/albums/m14/thebutelr/117_9098.jpg

[200x newby]

only one word... SEXY!!!!!!!!!!

[oldsking86]

Looks pretty slick man! Must sound like a beast! good stuff

[jsimonh]

That looks sweet! Makes me want one:lol: . I think I might just have to try that in the not to distant future:naughty: . I would really like to see a full ride report on it versus your old supertrapp, if you can be unbiased:D .

[youngbansheeman]

DAmn looks nice!

[NOS_350X]

Here is the pic of mine. :beer I love it, But the supertrapp i had i liked more (but its not your typical supertrapp) The thing i do like about it is i have a WB E-seris on it right now, but it will accept ANY 400ex slip on, and bolt right up with no problems. So if i am un satisified with the exhaust i have perty much an unlimited selection of exhusts to choose from.

[thebutelr]

Well I finally got the new exhaust stud nut and new exhaust gaskets to fix my leaks and found a good way to mount the pipe so the end cap is not hitting the grab bar. This pipe sounds awesome, there really isn't any other way to describe it. Nice deep tone that sounds very crisp all the way through the rpm range. I haven't had time to dial the carb in to this new exhaust system but once I do I will let you guys know how the power is compared to the supertrapp system! I will have some pictures up tomarrow of the new mounting location and the rest of the bike cleaned up a bit! :beer

[jsimonh]

Well I finally got the new exhaust stud nut and new exhaust gaskets to fix my leaks and found a good way to mount the pipe so the end cap is not hitting the grab bar. This pipe sounds awesome, there really isn't any other way to describe it. Nice deep tone that sounds very crisp all the way through the rpm range. I haven't had time to dial the carb in to this new exhaust system but once I do I will let you guys know how the power is compared to the supertrapp system! I will have some pictures up tomarrow of the new mounting location and the rest of the bike cleaned up a bit! :beer

Glad to hear you got her all buttoned up:w00t: . I'm looking forward to the comparisons:D . Hurry up with the finished :pics: ! You can't keep us waiting to long!

[NOS_350X]

Did you grind the welds on the headpipe?

[thebutelr]

Did you grind the welds on the headpipe?

No I haven't yet but since I finally got it to where it has a set mounting location and everything sealed up it will be the next thing I do, just have to get ahold of a dremel. Does grinding down the welds really make that much of a difference? If it does is it only performance wise or does it help the sound too?

[thebutelr]

Here are some pics of the new mounting location for the HMF. http://i100.photobucket.com/albums/m14/thebutelr/117_9212.jpg
http://i100.photobucket.com/albums/m14/thebutelr/117_9213.jpg
http://i100.photobucket.com/albums/m14/thebutelr/117_9209.jpg

[tyman]

umm... the grab bar looks a little bit off... haha.. but hey it looks awesome anyhow!!

[Louis Mielke]

is that a clark tank or IMS?

[OldSchoolin86]

No I haven't yet but since I finally got it to where it has a set mounting location and everything sealed up it will be the next thing I do, just have to get ahold of a dremel. Does grinding down the welds really make that much of a difference? If it does is it only performance wise or does it help the sound too?
I didn't notice a sound difference but once you grind them down you'll be suppried how much larger the holes are.

[thebutelr]

umm... the grab bar looks a little bit off... haha.. but hey it looks awesome anyhow!! What do you mean it looks off?? Like crooked? :confused: If so I kinda noticed that too and I think its how my camera was angled because in person it is perfectly straight.

[thebutelr]

is that a clark tank or IMS?
It is a clarke tank. :beer

[jsimonh]

That looks REAL good.:w00t: Did you take it for a spin after you snaped those pics?

[cragster]

That looks absolutly great! How much difference did it make with the 400ex carb and exhaust together?

[Billy Golightly]

Great work, looks extremely nice!

[thebutelr]

First of all thank you guys for all the nice comments you have left about the pipe! :beer I really haven't had much of a chance to see about getting my pipe dialed in but it is kind of confusing me. My bike for some reason puffs out a little smoke on start up and when I started it up I noticed that there was smoke coming from the head. I figured that since my old header didn't leak like this I would be fine on the exhaust gaskets but could this be making the bike so lean that a 195 jet won't even color the plug on a plug chop??? :confused: The bike really feels very lean with flat acceleration and no balls, and now pops excessively on deceleration when it didn't at all with the supertrapp. I knew I was going to have to jet up on the main but this a bit overkill! Oh yeah I was running a 178 with the supertrapp FYI :eek: .

[NOS_350X]

Sounds to me like you have an air leak on your intake or your engine is just running that good. Rember, i was a a 220 main with the 400ex carb. What type of fuel are you using? I say you take some starting fluid or carb cleaner spray it around the intake and see if that changes the rpm's that will tell you if you have a leak on the intake side. Also is the bike running hot or heating up fast? Keep going bigger on those jets until you get her where you want, pull out the drill bits if you MUST. And DONT FORGET THE PILOT JET. Also the needle helps. I took off my choke flap on the 400ex carb for better flow and herd of screws comming off of them and going into the engine. I had it dialed in so well that i never had to choke it (couldnt) to start it, and still dont. You can also get boysen Quick shot thigns for the 400ex carbs it helps on the bottom end. Also the PowerNows help alot on the bottom end.

[thebutelr]

I'll go out and check that today because I just might have bumped the air boot off of the carb or the intake manifold while I was messing around with that pipe :wondering . It does act kind of similar to when the boot came off a few weeks ago:rolleyes: . If its not the intake I guess that this pipe flows air a TON better than the supertrapp! (Lets hope not because I really would like to stop having to buy main jets!! :lol: )
EDIT: Oh yeah I am running 92 octane fuel.