1982 ATC 200 rebuild&upgrade experts help!

[C-lab]

Alright, new member here. I got this ATC 200 in rough shape a few years back for free. Put some gas in it and rode it around my shop just doing wheelies and riding on the side 2 wheels on pavement and gravel. The thing smoked like a train, clutch slipped, but it ran ok. Recently I took it off road for the first time and was hooked almost immediately.

So, now I'm fixing it up a bit to make it run and ride better. Not worried about looks because I don't want to have to worry about keeping it nice.

Tore down the engine and found this.
http://s844.photobucket.com/user/cbc...novh1.mp4.html

[yaegerb]

don't know how you loaded that pic, but I can't open it. Try loading it again as a .jpg. What is it we are looking at, the crown of the piston?

[RUNMEDOWN]

From the small pic it looks like the ring is on top of the piston, but having issues loading a bigger version of the pic. If that's the case it should not be in there.

[C-lab]

Ok, I appreciate the replies so far, but the pic is a short vid and it isnt my question. Sorry for not giving all the info up front. I wanted to make sure the video worked, then add more. So I submitted the thread thinking I could add more right then, not knowing it would have to go to the mods first.

The video just shows that the piston is loose in the bore. Now you can imagine how much it smoked! I actually felt bad for those behind me, so I'm fixing it.

Here is the piston skirt.


So I ordered a 66mm 12:1 Wiseco piston and rings for it. I know many do not recommend the 12:1, but I've seen others say they ran it and it pull started just fine, so I went for it.

I sent the jug out to the machine shop where they bored it and resurfaced the deck. I also had them level up the cylinder head mating surface.

Did a conservative port job (I know some don't recommend trying this at home). My brother did the port work and he's done extensive reading and gotten good results in the past. I also polished the combustion chamber.

[yaegerb]

Alright, new member here. I got this ATC 200 in rough shape a few years back for free. Put some gas in it and ride it around my shop just doing wheelies and riding on the side 2 wheels on pavement and gravel. The thing smoked like a train, clutch slipped, but it ran ok. Recently I took it off road for the first time and was hooked almost immediately.

So, now I'm fixing it up a bit to make it run and ride better. Not worried about looks because I don't want to have to worry about keeping it nice.

Tore down the engine and found this.
http://s844.photobucket.com/user/cbc...novh1.mp4.html

ok, I see it now. Time for a new piston/rings/bore. That's quite a bit of slop. Also, check the crank while you are in there. you should have zero up and down play and very minimal side to side.

[yaegerb]

looks good. Crank in good condition?

[C-lab]

I'm not sure about the crank. Bottom end had no noises before I pulled it apart.

I installed the piston and put everything together following the service manuals instructions. I also installed a DG performance exhaust. I have a Mikuni TM28 flatslide but it isn't installed yet. I also installed a dial a jet and 100 octane gas.

Fired it up and there is a bad tapping noise. I think it's most likely the wrist pin but not sure. I'll be tearing it back down to find the sound. I'm sure most of you know how disheartening that is, but oh well, I apparently didn't do something right.

I fixed the clutch by installing EBC friction discs and HD springs before I tore the engine down. This clutch grabs hard now. Glad to have that problem solved.

Now to the questions. These are just the beginning as I'm sure I'll come up with more.

What cam should I run? I'm wanting to go with megacycle either .370" or .435". I'm thinking .370" because I'm not racing this thing and want to keep my bottom end while adding more up top. Seeing the specs of the factory cam, just the .370" would be a huge upgrade over stock. I've seen a couple people talk about the .435" and all the power it makes and since I'm running the 12:1 piston I'm wondering how bad bottom end would suffer? Anyone with actual experience on this? Opinions welcome also.

Planning on getting a new timing chain while doing the cam. How many have degreed in their cams and should I spend the dough to be able to do this?

The Mikuni says that it comes with a 15 pilot and 180 main jet. How should I go about trying to jet this setup? What and how many alternate jets should I have on hand?

Also, the lever style decompression vs the auto cable style. Do you have to hold down the lever while you pull? Mine has the cable style. It wasn't hooked up when I got it and I didn't even know what it was. I hooked it up and saw it moving but didn't notice any change. I'm guessing that's because my compression was so low before the rebuild. But now with the high compression, it's like it works sometimes but sometimes the compression overtakes it and jerks my arm like crazy. I've unhooked it for now. It's way harder to pull, but predictable and my shoulder is happier.

Thanks for the help guys!

[yaegerb]

I'm not sure about the crank. Bottom end had no noises before I pulled it apart.

I installed the piston and put everything together following the service manuals instructions. I also installed a DG performance exhaust. I have a Mikuni TM28 flatslide but it isn't installed yet. I also installed a dial a jet and 100 octane gas.

Fired it up and there is a bad tapping noise. I think it's most likely the wrist pin but not sure. I'll be tearing it back down to find the sound. I'm sure most of you know how disheartening that is, but oh well, I apparently didn't do something right.

I fixed the clutch by installing EBC friction discs and HD springs before I tore the engine down. This clutch grabs hard now. Glad to have that problem solved.

Now to the questions. These are just the beginning as I'm sure I'll come up with more.

What cam should I run? I'm wanting to go with megacycle either .370" or .435". I'm thinking .370" because I'm not racing this thing and want to keep my bottom end while adding more up top. Seeing the specs of the factory cam, just the .370" would be a huge upgrade over stock. I've seen a couple people talk about the .435" and all the power it makes and since I'm running the 12:1 piston I'm wondering how bad bottom end would suffer? Anyone with actual experience on this? Opinions welcome also.

Planning on getting a new timing chain while doing the cam. How many have degreed in their cams and should I spend the dough to be able to do this?

The Mikuni says that it comes with a 15 pilot and 180 main jet. How should I go about trying to jet this setup? What and how many alternate jets should I have on hand?

Also, the lever style decompression vs the auto cable style. Do you have to hold down the lever while you pull? Mine has the cable style. It wasn't hooked up when I got it and I didn't even know what it was. I hooked it up and saw it moving but didn't notice any change. I'm guessing that's because my compression was so low before the rebuild. But now with the high compression, it's like it works sometimes but sometimes the compression overtakes it and jerks my arm like crazy. I've unhooked it for now. It's way harder to pull, but predictable and my shoulder is happier.

Thanks for the help guys!

Tapping noise: Valve lash set correctly? If you are pulling it back apart grab the rod and pull up and down. There should be zero up and down movement. Move the rod side to side and check the gap with a feeler gauge and follow the tolerances in the manual. Small end rod should have zero play in the wrist pin.

Cam: I have had good luck with webcamshafts. If you want a better cam than stock go with the 340b. The next upgrade is the 389a, but that will require a spring kit with titanium retainers and you will need to hardface your rockers. Webcams does hard facing too. I would leave the stock cam gear on the cam and go with an HD cam chain. Don't worry about degreeing it, I have found it to add incremental HP and tons of headache.

Carburetor: I think I ended up with a 170 main and a 30 pilot on my 28MM Mikuni roundslide. I can check the actual specs tonight when I get home and I will edit this post if necessary.

Decompression lever: If you aren't using it anyway, you could always swap out the rocker box with a first gen 200x head, which doesn't have the decomp in it.

[C-lab]

Valve lash was set correctly and rechecked. Is it possible that with the little bit of surface material removed from the cylinder and head, plus the 12:1 dome piston and regular head gasket, not the MLS that I removed, that the piston is smacking the bottom of the head? I don't think so, but want to get your opinions. Also, should I go back with the MLS? If so, where can I find a top end gasket kit that has it?

Here is a pic of the trike how it sits. As you can see, I have a leak in the front tire I need to figure out and fix. This just recently developed.


I followed the LED light install guide and got this:


One of the mounts is a little crooked which I need to fix. I sprayed the housing with black wrinkle paint because it was in bad shape. I got it used off another bike because it was missing completely. Since the rest of it isn't in great shape, I figured shiny red paint would clash badly, so I went a different way all together.


It has brand new back wheels and 25X9-12 tires.


I did this because someone had put these little 22X11-8 numbers on there. I figured with no rear suspension the bigger tires would smooth out the ride a tiny bit.


Can anyone speak to the difference in steering ability with the current front tire vs a regular knobby like I have in the back? I'm thinking the current front might grip better to help me turn but I'm not sure.

That's it for now. More to come!

[C-lab]

Also, it has a plastic gas tank. Not sure what it came off of but it fits just fine.

[yaegerb]

What is an MLS?

[Jd110]

It's a head gasket. MLS multi-layered steel


Sent from my iPhone using Tapatalk

[yaegerb]

It's a head gasket. MLS multi-layered steel


Sent from my iPhone using Tapatalk

Ah, thanks!

If the piston is hitting the head you will know when you pull it off and see marks in polish job.

[C-lab]

It's a head gasket. MLS multi-layered steel


Sent from my iPhone using Tapatalk

Yep, you nailed it. Now how do I undo the fact that when I was trying to hit the like button on my phone, the little buttons were so close together I hit dislike on accident? I then hit the like button but now it just shows both. Makes me look like I'm losing my mind liking and disliking something at the same time!

[C-lab]

If the piston is hitting the head you will know when you pull it off and see marks in polish job.

Yep, exactly. The tear down will tell all, but just wanted to get some guesses as to whether that was even a possibility. We will see...