Header options on ATC 200/200x pre '86

[yaegerb]

This is what the new header will be bolting up to:

Out of curiosity, why a 30MM? I would think with the mods you are doing a 28 or even fat jetted 26 would get you there.

[Dave8338]

Of all the pipes I have ran across the nicest and best power producer was the bassoni. Hey are rear and hard to find but if you can get one your golden. Next up is the super trap stuff.

Outside of that, they are the same except the DG stuff is Chinese junk.

I've looked for a few years for a good Bassani and all I could turn up were well rusted, pitted pieces of junk. DG... out of the question.

I've tried some googling, but haven't really come up with one that looks like yours. Yours looks a little longer than stock. Will you be able to use the stock airbox or are you gonna run an open filter?

It is quite a bit longer than the stock 200X intake and the angles are different. I had to notch and invert fill the backbone just to get the carb to clear and have room to run the Y-splitter cable. Also, the stock upper shock mount on the 200x frame was in the way, so I made a bit of a change there, too. It won't accommodate the stock air box unless it could be relocated.

Here was my solution:

[Dave8338]

Out of curiosity, why a 30MM? I would think with the mods you are doing a 28 or even fat jetted 26 would get you there.

Couldn't find a 26-28 with the accelerator pump. Also looking to open up the top end range a bit. It won't surprise me if jetting the thing correctly, will take a while. I didn't want to lose all of the bottom end torque so a longer intake will hopefully offset that a bit. All trial and error at this point. OK... there are a few calculated changes, too.

[ironchop]

whats the story on that modded frame?....nevermind, I had missed where you said you modded to clear the new carb setup


AND......what header do you need? ATC200 or 200X......reason I ask is because I think I have a spare header with no muffler for a cobra setup on a 200S. I`ll have to look again to be sure I didn`t sell it and forget.

[Dave8338]

I've decided to go the route of reworking a TRX stainless header, based on tube sizing. If you do have the Cobra header, what size ID is it?

There was more to it than just the carb setup, for hacking this thing apart and making changes. I did that part of the work a couple years ago.

This was the other reason:

[ironchop]

I`ll check the shop and see and get back to you.

Do you have a thread for that mod above? Because this is precisely what I was mulling over to do to my 200X as I would rather have the progressive linkage swinger setup in the rear rather than stock X swinger as well.

[Dave8338]

I`ll check the shop and see and get back to you.

Do you have a thread for that mod above? Because this is precisely what I was mulling over to do to my 200X as I would rather have the progressive linkage swinger setup in the rear rather than stock X swinger as well.

Here is about as close to a build thread, as I got with it. Not jammed full of all the little details but enough there to get an idea of what goes into it.
http://www.3wheelerworld.com/showthr...w+to+the+fourm

I too, didn't like the "pogo" ride of the original 200x bikes. Once you've ridden a 250R (or any bike with the progressive suspension, for that matter) the rest fall a bit short, for someone with a bad back.

[ironchop]

I too, didn't like the "pogo" ride of the original 200x bikes. Once you've ridden a 250R (or any bike with the progressive suspension, for that matter) the rest fall a bit short, for someone with a bad back.

Thanks Dave.....yeah, I love my little X after some topend work and a Megacycles setup made a major difference in power but @ 240lbs, I`ve pushed the suspension way beyond its design capabilities. I got an A2 on the bench to build but I would still like to keep my X.....one time a hard run at the tabletop @ TF and my overzealous self nearly snapped the frame when I landed so something needs to be done with the chassis....I`ve had several Pro Link Hondas and they were very supple to land compared to the X

[Dave8338]

Thanks Dave.....yeah, I love my little X after some topend work and a Megacycles setup made a major difference in power but @ 240lbs, I`ve pushed the suspension way beyond its design capabilities. I got an A2 on the bench to build but I would still like to keep my X.....one time a hard run at the tabletop @ TF and my overzealous self nearly snapped the frame when I landed so something needs to be done with the chassis....I`ve had several Pro Link Hondas and they were very supple to land compared to the X

AWESOME ! ! ! Wish I had been there to see it ! Trixy rides VERY smooth. Flat, too. Loves to sit in the middle of a gravel road throw stones.



Thought I would give a few here, an insight as to what lies beneath the eventual shiny skirt....

Dug this O'le thang out of the cupboard:

[oscarmayer]

just remember, the bigger the pipe does not always = more HP. these smaller motors need "some" back pressure to produce decent power and torque. if you take that way you will definatly hurt performance. I recommend never goign more than 1/4-1/2" larger than stock. i think stock is 5/8" so a 3/4 t max of 1" is all i would go to. double check that stock size to be certain.

1/4" larger than stock if mods but no stroke, 1/2" larger if stroked. that is all i would ever do in sizes larger than stock. this ensures you get max everything.

[Dave8338]

just remember, the bigger the pipe does not always = more HP. these smaller motors need "some" back pressure to produce decent power and torque. if you take that way you will definatly hurt performance. I recommend never goign more than 1/4-1/2" larger than stock. i think stock is 5/8" so a 3/4 t max of 1" is all i would go to. double check that stock size to be certain.

1/4" larger than stock if mods but no stroke, 1/2" larger if stroked. that is all i would ever do in sizes larger than stock. this ensures you get max everything.

Good solid advice ! I'm going to be able to tune for back pressure, by adding or removing discs from the Super Trapp. Hoping that I can come up with a combo that not only breaths well, but isn't too loud. Loud is for young'Ns !

[Dave8338]

Spent a little time this morning, cleaning up the last of the port work on the head. Tight little spaces to work around and the palm of my hand, is about the size, of the head. The pencil/ mini die works well. Takes time and it sounds like sitting in the dentist's chair for a few hours at a time, , , listening to the drill.

[Dave8338]

Spent a little more time in the shop tonight on the cylinder head. Ported and about half done with the finer details. Valve guides and clean up of the exhaust side, are still to be done.

Intake side, ready for action:


Exhaust side needing another hour or two of attention:


And one of the hemi head:


Still a few hours left getting things as I want them but for now, progress has been made. Futile effort in an attempt to get the pre '86 head to breathe.... time will tell. A 185 only had two valves, after all.............

[Dave8338]

More time on the exhaust port yesterday afternoon, before the game. Had to pick up a few more dremel bits that were small enough to fit in and around the valve guide area, without hogging out too much material on the outer radius. I though my selection of 1/8 die grinder bits was fairly healthy. To date, I added 10 additional bits to the mix. Not used to working on ports this small. Next to NO room and even with the seats taped up and being extremely careful not to under cut them too much, it is tight, tight, tight!

Should have the exhaust port finished or close to it, by tonight...

[oscarmayer]

remember be very careful where you are taking material from. too big and it will loose power. the reason is port volocity.
You have to maintain that through the whole process or you cause a backpressure build up and that slows the machien down making it run like doo-dee.
This is why we have always said you must have a flow bench to port a head properly or you may just be causing a problem. That being said, you could have just port mathced the ports 1" into the port chamber and do some very slight smoothing and that woudl have been ok. right now, you have modified ti so much, that it is hard to tell if it will have a problem. I am concerned about the pre-seat chamber sizing. it seems to be a big cavern now and a place where you could end up with back pressure buildup rather than flow, but you will have to chekc it out to see. these smaller CC motors like small ports and they live the ports not to change much exept into a very slight conish style shape. having weird buldges always has caused problems on the heds I worked with. If I find a pre-ported head, I alwyas have to flowed before I used to to see if it was done right or just hogged out. These small CC motors do not do well with "hogging" style at all.

anyway, good luck and I hope t turns out good. (sorry i am not trying to be a debbie downer on ya, only trying to give you honest info)