1982 atc185s, teach me something.

[Laredo]

I have a little 185, ive had it for about to years. Finally got it running right, but im curious what kind of options do i have?

It has a .75 over bore mid 2mm over lift cam. And a hefty gear reduction(6.13 is the current gear ratio) on 25" tires.

Do i have any head options? Larger valves, port and polish maybe? 4 valve? Any clutch options? Can you stroke it? Are high compression pistons worth it?

[ps2fixer]

Building up an engine is pretty expensive, just personal opinion, but I'd start with a more sporty machine if you prefer speed, or a more utility & shaft drive machine if you prefer mud and such. A stock 350x is a torque monster, does exactly what you tell it to do, etc, my fav machine. If you like utility, check out a 250es or 250sx.

Not saying the 185 is a waste or anything, just before you spend a buch of time/money on it, just making you aware of other options.

Anyway, the 185 is effectively a 200/200s engine, a fair few parts interchange, and you can switch the top end & piston over to turn the 185 into a 200. The 200x cylinder has the biggest fins for the best cooling. There was a some 200 series motorcycle engines that should be similar, like the XR200 and XL200, don't know much about them but might be a place to look for performance parts. I think the cam interchanges, but the over board kind of goes to waste if you change out the cylinder.

I don't follow the 200 series models as much as the others, I personally target 250cc+ models only for keeping, anything smaller I buy to part out or fix up to sell. I suspect you can push a 200 series engine pretty good for power, but expect to pay for it too. Easiest upgrade is displacement though for power.

[shortline10]

This is my 185s , read up , lots of options for your machine .
http://www.3wheelerworld.com/showthread.php/140972-Project-185s-High-Performance-ATC-Full-Suspension

[Laredo]

Shortline10 that machine is amazing! So engine build recap:
- 200x jug '81-'85
- .435 megacycle cam,
- ported head
- 24mm Mikuni Sudco carb w/ K&N filter
- super trap exhaust
- barrnet hd clutch kit

What kind of piston are you running. Wiseco? Cr? 10.25:1 or 12:1? What bore size? BAPP Copper head gasket? Oversized valve heads?

My bike is used for fast paced mountain/back country trails and mudding with large tires 25" now. About the go to 30s, i have an adequate gear reduction (roughly 60% at the chain).

Do you think a build similar to your set up, would function reliably and fit my application appropriately?

[ps2fixer]

FYI, the 200X was only made 83-87, guessing the 81 was just a mistype for 83 though. Just trying to help keep data accurate on the site.

[Laredo]

Sorry i actually meant 83-85. In 86 i think they changed the head shape and design and the stroke length

[ps2fixer]

Yea, 86-87 200x was basically a redesigned engine. I don't think it's the same "family" of engine as the other 200 series engines.

[shortline10]

26mm vm mikuni carburetor with mossburger intake manifold
Wiseco 10.25 piston std bore


Very reliable and fast .

I could have gone a little more aggressive with a 28mm mikuni and 12.1 piston but didn’t want to have to run race fuel .





Shortline10 that machine is amazing! So engine build recap:
- 200x jug '81-'85
- .435 megacycle cam,
- ported head
- 24mm Mikuni Sudco carb w/ K&N filter
- super trap exhaust
- barrnet hd clutch kit

What kind of piston are you running. Wiseco? Cr? 10.25:1 or 12:1? What bore size? BAPP Copper head gasket? Oversized valve heads?

My bike is used for fast paced mountain/back country trails and mudding with large tires 25" now. About the go to 30s, i have an adequate gear reduction (roughly 60% at the chain).

Do you think a build similar to your set up, would function reliably and fit my application appropriately?

[Laredo]

On the megacycle .435 cam, is the needle bearing kit they offer worth it, or is it a waste of money? Apparently the kit comes with a new mounting plate and 2 needle bearing no machining required.

[shortline10]

The 435 roller cam is a very nice part .

[Mullet_Man]

High compression heads could add a lot of power to that machine only downside is then you need to machine the head and get larger valves and carb and lightened crank and cam and all that so your talking latta cash for a 185