Atc 200x build

[1969camaro]

Hey I have a 85 ATC 200x that I'm in the process of building I'm looking for performance parts especially camshaft. I've got a jug bored to 66.5mm with 10-1 compression piston. And the upgraded valve springs just wondering if anyone my have a nice bump stick they might wanna let go of. The plan for the bike is black frame, engine, tank, plastic except for super scoops. And a red seat cover. Trying to build one similar to what I had as a kid, it was hilarious having people trying to figure out what was done to it.... It had a very rough idle

[DohcBikes]

Welcome to 3wheeler world!! Sounds like an interesting build.

[1969camaro]

Its a wiseco 66.50 they still offer a 67mm piston and 10.25 comp, and thanks glad to be here

[DohcBikes]

That's right I forget they sell them that large because I'd not run the sleeve that thin, but I'm sure yours will be fine. Any more pics for us, we love pics.

[1969camaro]

Sure I'll post more pictures as it progresses so no one has a nice cam they would part with? I have the 420 lift springs

[x-rider]

Looks good bud. Kinda the route I'm going.

[1969camaro]

Anyone know the rocker arm ratio for it?

[DohcBikes]

It's not something that is advertised for these engines but if you want to find out easily just measure max valve lift and divide it by cam lift.

[Leevvii]

perf cams for 200X
http://www.webcamshafts.com/index_blank.html?pages/vehicle_search.html

[Leevvii]

very bloody nice mate, love the black plastics

[1969camaro]

Is it 1.25 ratio rockers?

[DohcBikes]

I don't know, is it? And if you don't mind me asking, why do want to know? It's not like a 350 where you can just buy 1.6 rockers and get more lift. They just dont have room in the rocker box and even if they did they're aren't any options that I know of. Seeing as how the rockers are in direct contact with the cam, OHC engines don't really allow the tolerance that a pushrod design can allow for when substituting rockers with a larger ratio.

[1969camaro]

Cause I'm trying to figure out what cam is in a parts bike that I got. I know the lobe lift I'm trying to figure out what to multiply it by

[DohcBikes]

Already told you, post #8.

Do you have a dial guage? I bet you do. Measure your max valve lift, at the valve itself, then divide that by the cam lift. Presto, rocker arm ratio. Some might suggest doing this with zero valve lash, but it makes no difference. Max lift is max lift, regardless of valve clearance at TDC.

[1969camaro]

The head is at the machine shop

[1969camaro]

Just stay out of this thread, if anyone else knows the ratio let me know

[1969camaro]

Also pulled the exhaust off the third 200x I got, anyone have and idea what muffler this is?

[1969camaro]

OK bad news my gas tank has a pin hole so I'm gonna need to find another, I ordered a 10.25 compression piston and megacycle cam .370 lift and 273 @.040. Also got some brake parts in today

[DohcBikes]

I thought you already had your cylinder bored?


I've got a jug bored to 66.5mm

Doesn't make much sense to bore the jug then order a piston. Lot of money you're investing to do things that way.

[1969camaro]

I have several jugs, this one was rough cut to under 66.5 I didn't have the piston yet to do the final hone. All the pieces are at the machine shop just waiting on the cam and I'll fix old smokey pic attached

[1969camaro]

The machine shop got all the machine work done to the head and the jug so I went to pick it up and darn if it doesn't look nice. And just to recap its 66.5mm wiseco 10.25 compression piston rebuilt 200x head with 420 lift springs and retainers. Now its just time to wait for the megacycle cam!!!! And I got pics because everyone loves pics

[DohcBikes]

Do you always blast your cam journals? Looks nice!

[yaegerb]

x2...you better scotch brite those journals.

[bkm]

Or use the megacycle roller cam and not worry about it.

Sent from my SM-G900V using Tapatalk

[DohcBikes]

Or use the megacycle roller cam and not worry about it.

Sent from my SM-G900V using TapatalkI see the cam he's using, just curious.

Don't forget the little rubber plug between the head and rocker box that controls oil to the cam.

[axeman24]

hello 3ww I am an new member but a long time reader

I am currently rebuilding my original 85 200x motor from my running auto x (this bike was left out for years and even flooded in hurricane sandy)

ive been working on it for months to get the piston out (top end was seized tight)

I finally got the piston to move but on the last hit I cracked the bottom of the sleeve my local shop wants 300 to re-sleeve only

my question is for a replacement jug I have read that the xr200r top ends are interchangeable but cannot find definitive answer for the jug

I can get a oem used xr200r jug on ebay for $50 and have it honed and get a high compression piston all for around 250 if I go that rout do I use a xr or x piston or is it the same

the only info I see on jugs is the fin size is different

any thoughts on the aftermarket jug/heads on ebay anyone ever use them

thanks again and I hope to contribute and get help from this forum

[bkm]

I see the cam he's using, just curious.

Don't forget the little rubber plug between the head and rocker box that controls oil to the cam.
I just thought since he mentioned megacycle, he wasn't worried about journal smoothness?

[Roach21x]

Any updates on your build?

[1969camaro]

Yea just now getting back to it, I'm gonna work on old smokey first. Anyone have a recommendation for a camshaft I want this thing to beat the ground!!!

[1979atc]

Also pulled the exhaust off the third 200x I got, anyone have and idea what muffler this is?

Pretty sure your silencer is a Curtis Sparks.

[jeepguy922]

get with WEB CAM, they make a .395/.395 lift cam that is close to what Sparks and Powroll made. you might need more head work and a bigger carb to get the most out of it.

[8DO83]

Hey I have a 85 ATC 200x that I'm in the process of building I'm looking for performance parts especially camshaft. I've got a jug bored to 66.5mm with 10-1 compression piston. And the upgraded valve springs just wondering if anyone my have a nice bump stick they might wanna let go of. The plan for the bike is black frame, engine, tank, plastic except for super scoops. And a red seat cover. Trying to build one similar to what I had as a kid, it was hilarious having people trying to figure out what was done to it.... It had a very rough idle

I like the seat! Is that off a 400ex I want one like that!


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[1969camaro]

I've decided to go with the webcam .375 lift can for the new bike I got, I should have made separate threads for each