400ex head pipe on a 350x???

[oldtoys72]

So I was perousing fleabay looking for a decent head pipe upgrade for my newest project 350x. A guy is selling a head pipe for a 400ex that he is claiming will also fit the 350x. Do any of you know if it will actually work? I can't really tell from just looking at the pictures.

[fabiodriven]

It will not fit without some modifications.

[big specht]

Why??? we were thinking of doing that too

[fabiodriven]

Why??? we were thinking of doing that too

Why what? :wondering

[Thorpe]

Why do we have to modify it??? Um... Because it doesnt fit in stock form....

[big specht]

Why what? :wondering

For the guys with the 500cc 350s

[fabiodriven]

For the guys with the 500cc 350s

Well that clarifies everything.

[Dirtcrasher]

For the guys with the 500cc 350s

Doesn't matter, the 400EX has the same ID as the 350X pipe.

To use it you have to cut off and use the 350X flanges and cut/bend/tweak the headpipe to fit. Waste of time IMO..........

[NOS_350X]

You dont have to cut the flange at all.

you have to cut the rear section of the head pipe above the kicker, grind a bit to tilt the rear section up, weld it back together. its really not much work at all.

[Dirtcrasher]

Yet still the same ID, correct??

[big specht]

some of the aftermarket pipes had a bigger inside dia

[Dirtcrasher]

^ I know that, but for some reason people felt the 400EX in stock form had a larger ID head pipe. People have told me this isn't true so I wonder what the advantage is?

[TheRealFatShady]

Being brand new and cleaner, cheaper. That's the only reason I can think of.

[Shorty]

^ I know that, but for some reason people felt the 400EX in stock form had a larger ID head pipe. People have told me this isn't true so I wonder what the advantage is?


The advantage is that once you modify the 400EX header corectly you can use almost any aftermarket slip on thats made for the 400EX.





Shorty:D

[Dirtcrasher]

Most members here don't or can't shell out the $$ for a slip on when they can buy a whole Cobra or DG for the same price. Don't get me wrong, I do not care for cobra or DG but I can't buy a 200$ used slip on either......

Fortunately, I have Supertrapp systems on most of my machines.

[Shorty]

Most members here don't or can't shell out the $$ for a slip on when they can buy a whole Cobra or DG for the same price. Don't get me wrong, I do not care for cobra or DG but I can't buy a 200$ used slip on either......

Fortunately, I have Supertrapp systems on most of my machines.


I understand that. But you get my point that if the header conversion is done correctly you can use NEW school exhausts. And yes they are some what pricey. But I mean any New parts that you can retrofit on on old trikes is like almost finding a wad of 100$ bills on the ground haha.



Shorty:D

[NOS_350X]

I would also like to mention, i have read many times that the OEM headpipe on the 400ex flows better than any of the aftermarket larger dia. head pipes. Its built right, and perfect, Grind the welds where it bolts to the head and your better than anything aftermarket.

Then you also have the options of the 400ex/450 exhausts that will just bolt on. It gives you MANY more options for the exhaust, the Dg and Cobra pipes are CRAP.

[oldtoys72]

I had forgot about this thread, like someone stated I wanted to go with this head pipe because its newer, readily available and far cheaper than what the beat up 350x ones are selling for. Also then I can go with a newer tail pipe, in fact I just picked up a 450R pipe for the trike. From the sounds of it the modification of the head pipe isn't to bad. If someone has done this can you tell me what exactlly you had to do to make it work? Thanks!

[Dirtcrasher]

See, thats the problem. I won't throw anyone under the bus but I clearly read that the flanges from the 350X had to be used on the 400EX pipe. The person stated they just cut the pipes and swapped them, then rewelded them back together.

[NOS_350X]

Dirtcrasher, I have doing the 400ex headpipe 450 canaster about 15 times to customer bikes. and have NEVER cut the flanges.

[oldtoys72]

Dirtcrasher, I have doing the 400ex headpipe 450 canaster about 15 times to customer bikes. and have NEVER cut the flanges.

It seems as though you have done this numerous times and have a good grasp on it. Could you please tell me what EXACTLLY needs to be done to make this work? There have been a lot of things thrown around on this thread and would sure appreciate a clear picture of what it is I will have to do to make the head pipe work. Thanks

[big specht]

I second the pic idea

[kiser]

I tried to put a 400 head pipe on my 350 and the stud holes in the flanges wouldnt line up. The 350 studs were straight across the exhaust port from each other. The 400 flange holes were offset enough i couldnt even re-drill them to fit.

[NOS_350X]

http://i59.photobucket.com/albums/g285/NOS_350x/IMG_8023.jpg

http://i59.photobucket.com/albums/g285/NOS_350x/IMG_8019.jpg

In these pictures you can see i havent touched the flanges. What a suprize, it works. I think you needed to try a little harder i have never had a problem with them.

http://i59.photobucket.com/albums/g285/NOS_350x/IMG_8024.jpg

You can see where the crack is coming, thats where the weld was. The pipe slopes down, and hits the case without the cut and grinding there.
http://i59.photobucket.com/albums/g285/NOS_350x/IMG_8029.jpg

[oldtoys72]

So that's it? Just one cut, a little grinding to re-adjust the angle, one weld and your good to go? That's not hard at all! Thanks NOS

[NOS_350X]

Yup, thats it. Cut it off, Then bolt the headpipe to the bike, then bolt on the canaster, then adjust your grinding to adapt to both, some times you have to take off up to 1" to make it all line up, but its not hard. Tack it together, then remove to weld up.

[Dirtcrasher]

I tried to put a 400 head pipe on my 350 and the stud holes in the flanges wouldnt line up. The 350 studs were straight across the exhaust port from each other. The 400 flange holes were offset enough i couldnt even re-drill them to fit.

Thats what I heard so go figure.

I certainly don't doubt NOS_350X, I just HATE the conflicting information..........

[kiser]

Hmmm I guess it works. The pipe i had deffinately wouldnt work without changing the flanges. Did they change the 400 head pipe from different years?? I have no idea, but ''trying harder'' wouldnt make more materal to re-drill the one i had.

[Dirtcrasher]

Thats why I'd like to finally know what the deal is. Like you said, were certain years a bolt on with a grind and cut otherwise??

Someone send me a 400EX pipe, I'll figure it out :D

[Mosh]

Man..I gotta say.. I know DC and Kiser know 350x's. If it didn't work for them, the must have run into something wrong???

I have some friends that would like to know for sure on this before they pony up the cash for the parts.

[kiser]

If you find out Dirtcrasher, let me know lol. If certain years do work, id be happy!! 400 pipes are easier to find than 350x pipes. At least around here they are.

[kiser]

Mosh i do know that the pipes lined up with the exhaust ports on the 350 perfect but i just ran into flange issues.

[NOS_350X]

ive used pipes from 98-2004 at least.

[SWIGIN]

You guys do know that you can buy brand new 350x header pipes for $55 or so?

I also don't buy into that the 400ex header is better. Back when the 400ex first came out alot of pro MX guys used 350x aftermarket header and they made MORE hp then any 400ex pipe did.

How do I know this?......I helped do this. No hearsay or myths.

[oldtoys72]

Where are you finding NEW 350x head pipes for 55.00? Either way, I'm doing this more because once its done I will be able to use a new slip on exhaust. I sure hope this works out, the 450R pipe is headed this way, picked it up off fee-bay for 10 bucks! Now I gotta find a 400ex head pipe and get this upgrade completed!

[SWIGIN]

http://www.3wheelerworld.com/showthread.php?93091-for-what-its-worth....ATC-headers&highlight=