What year ATC cylinders fit an 86+ xr200r?

[wazzabie]

On 12/20/2018 at 10:14 AM, Doogee57 said:

  The head does not have bigger fins. The cylinder has bigger fins on more than just the top. They're also bigger on the cam chain side. For reference here's my 88 XR200 with an 83-85 200X big fin cylinder:

Doogee57 - With your atc200x cylinder on this bike did you have to modify the header pipe so that it would fit?  Did the cylinder cause any clearance issues with the pipe?

[Doogee57]

6 hours ago, wazzabie said:

did you have to modify the header pipe so that it would fit? 

  Nope. Dropped right on there just fine. Even clears my custom pipe which is closer to the cylinder than the stocker.

[rmhrc630]

So if I want the big fin mod, I just need an 83-85 atc 200 x cylinder? Are there bore differences and so should I rebore 200x to 200r spec? 

does 200x head need to be fitted as well ?

or will the 200r head bolt to the 200x cylinder?

[Chuck.]

On 12/18/2018 at 4:32 PM, Chuck. said:

The only difference is the ATC200X cylinders have slightly larger fins on the top than other ATC and XR185/200 cylinders. The years are 83-85 ATC200X (not 86-87 ATC200X), other ATC200s have the same fins as the ATC/XR/XL185/200 engines. I had a pic showing the difference but I can't find it.
Be careful because ebay sellers will advertise a ATC200 cylinder as an ATC200X. I had one seller post pics of a big fin cylinder and he shipped a normal cylinder, it got returned. To add to the confusion both cylinders have 192cc cast into the back side.
There are seven different part number for the various  185/200 cylinders, only one for the ATC200X.

 

NO on the ATC200 cylinder.  I posted the above earlier in this thread.  And all of the heads use the same head gasket and bolt on, but IMO the best heads  are XR200/R, but there minor breathing differences between casting numbers. Also use the late XR200R/CRF230F metal head gasket.

 

[rmhrc630]

15 hours ago, Chuck. said:

NO on the ATC200 cylinder.  I posted the above earlier in this thread.  And all of the heads use the same head gasket and bolt on, but IMO the best heads  are XR200/R, but there minor breathing differences between casting numbers. Also use the late XR200R/CRF230F metal head gasket.

 

Thanks Chuck

 

can you tell me has anyone made or sold an oil cooler for the 200?

[Chuck.]

I suggest installing a dip stick temp gauge before pursuing an oil cooler. I have one on my XR218R and the oil doesn't get very hot, IMO not enough to justify a cooler. The little R has an oil cavity in the roofp of the gear box that cools the oil. 

I think XRsOnly sells the dip stick temp gauge.

[AMSinator]

Modified 79' XL-125s engine w/ original 3-fin head w/ no decompression system stock in 81' 200r frame.

Converted to w/ 81' 200R cylinder, piston and 200R crank, Magneto/CDI set up. Powroll header, works well w/ 200 build.

1979 XL125s vintage MXer w/ 2Valve ATC200X center cases, X 5-speed, w/ X-big fin cylinder, X-big 4-fin head, w/ no decompression system stock. Bassani header exhaust for XL/XR-185s. XR200R stock 26mm Keihin carb

Left side ATC200X converted for motorcycle use, note upper engine mount was elongated to accommodate for longer ATC200X stroke.

Left side XL125s converted to 200 w/ 81' 200r parts.

The ports on the XL125s head measured the same as my stock 81' X200R head. I used telescoping gauges and measured length of intake and exhaust runners at equal depths.

I will hunt down measurements taken & post later.

 

Edited August 14, 2023 by AMSinator
add detail info.