None of the following references to atc200X apply to 86 or 87 models, those are a different critter all together.
Heads: atc185, xl185, xr185, atc200S/E/ES/M, xl200, and non-rfvc xr200 are all interchangeable. The 83-85 ATC200X head is interchangeable but different, it has a different shape to the bottom edge closest to the jug, and has no decompression lever in the cover. Covers should never be swapped from one head to another, they are machined together at the factory.
All ATC185-200's including the 200X had the same cam. XL185 had a very slightly longer duration cam, XR185-200 was longer still, but not by much.
ATC185 and 200/S/M had low compression pistons, about 8:1. The XL185 and 200X were higher, around 9:1 with a flat top. XR185 was 10:1 with a small dome. 185 bore is 63mm, 200 bore was 65 or 65.5 depending on model (going from memory here)
Cylinders: all 185 engines are the same. All 200 cylinders except xr200RFVC and atc200X are the same, and will drop onto a 185 bottom end. So will CB/XL125 cylinders, but they are smaller bore and shorter in height. 83-85 ATC200X had much larger fins, and are the most desirable.
Crankshaft: 185's and 200's have the same stroke. The right half of the crank differs between auto and manual clutch models. The left half of the crank differs between pull start and kick start models. The crank pins, and rods are the same. ATC200X has 2 thrust washers on the big end of the rod, all the others do not. Main bearing OD differs in size between certain models, but some can be swapped.
Crankcases: to the best of my knowledge the 185's and 200's are all the same except for the 200ES, the left case is different for the electric starter. Auto clutch models have an extension on the right side between the case and the clutch cover, and the cover is different than manual clutch models.
Shift drums, trans gears, and kicker gears changed too often and too drastically to list here, use the search function for lots of info. The 200X alone had three different sets of kicker gears in 3 years!
ATC185's & 200's had a 22mm carb, ATC200X had a 24mm carb, XL185 had a 26mm, and the XR185 had a 28mm. Intake manifolds differ.
That's all I know, or at least all I remember right now. And I have no experience with a Lifan, so I can't help you there. Hope this helps!
1985 Tri-Z 250
1985 ATC250R
Thanks man, this will help me when i go to get parts, as well as what upgrades i can do.
I see that i will have to change the crankcase to do electric start. Well, its not that important anyways. I can put a 200m motor if i want that.
Sweet write up, Drew! Well done, Sir.![]()
The Goal... All I Need Is The Time...
Bringing up an old thread... excellent write up and really answers some of my questions.
I have an '84 200x that either has an aftermarket cylinder or was bored to 67mm. The bore isn't thrashed but the cross hatch is gone.
Considered just running it with new piston and rings or finding out if I can use a cylinder from a different 200 on this motor but with the same head. I can't find any '83-85 200x cylinders out there.
Any thoughts on running a 200e, 200m, 200s jug on the 200x? The fins don't appear to be significantly smaller in the non-x models. And I'm just using it as a yard and woods machine.
Thanks.
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Sorry to bump up an old thread, but we're working on my son's 1987 XL185 (Canadian model), and have found this thread with some good interchange info. We are in need of a top end kit (piston, rings, gaskets, and cylinder). Our existing cylinder could also be re-machined, but is scored up due to previous owner running without air filter for a period of time.
I see some cheap kits on eBay, but notice that those labeled with XL185 show a cylinder that has a round flange on the side for what appears to be cam chain adjuster. See here as an example. Our engine does not have such provision.
Does anyone know interchange details for these two cylinder types? Could we put a cover plate over the round opening, and use it on our model of engine? Any guidance would be greatly appreciated. We'd like to order a kit including cylinder if reasonably priced, but can't find any on eBay without the round side opening. Thanks in advance!
The deck height on those cylinders are wrong , won’t work .
This kit looks like it will work .
If you have a place to over bore your cylinder that might be a cheaper route , you can go up to 66.5 mm safely
https://www.ebay.com/itm/26577985687...Bk9SR-z545yGYw
Last edited by shortline10; 12-03-2023 at 06:35 PM.
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Thanks for the reply. I had no idea deck height was different. Wow, you saved me some grief there!
Are the gaskets and piston the same though? Maybe I could grab one of those kits, and just re-machined my cylinder locally. That'd be quite a bit more economical than buying the very nice but more expensive kit you linked to. Thanks again for info.