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large fin cylinder

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I keep seeing about the ATC head with large fins.on a xr200.which they all look the same to me

What about a bored out 65.50 large fin cylinder from a atc

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That is big fin. You can see how the fins extend out past the head fins. Mine is marked 192cc. That does give more overbore options. On my early 200r the fins hit the heat shield on the pipe, so I am going to modify it slightly to fit better. It seems like a good way to go if you find a good cyl. To rebuild.

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I know what a big fan cylinder looks like everybody keep saying the cylinder headI really hope everybody on here knows the difference between a cylinder cylinder head but it doesn't seem like it

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On a stock head the cyl fins are shorter than the head fins.ImageUploadedByThumper Talk1400516538.827090.jpg

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Oh well, my bad. Sorry. I'll stop trying to help.

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Correct me if Im wrong but the header appears so close the the cylinder that it may be causing the cylinder to run hotter than normal?

If it was mine, I would wrap the pipe with pipe wrap to help keep the heat away from the cylinder and the float bowl on the carb also.

But maybe that's just me?

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Do you know what year and model that cyl is off of? And what exactly do you mean when you said it "gives more over bore options".........?

Old School Al

correct me if I am wrong OSA, but I think the 192cc cyl piston is slightly smaller than the 195cc cyl. I meant that you could bore to the xr200r stock piston size and still have a couple of over bores left. Just to increase overall life. Max overbore would be unchanged as far as I can know.

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So that would mean that the sleeve is a lot thicker as well as the fins are larger.

So with that in mind. The cases might be bored out larger to accept the larger sleeve?

Or is it just the ATC cases and cylinder fins larger but the M/C cases are not?

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correct me if I am wrong OSA, but I think the 192cc cyl piston is slightly smaller than the 195cc cyl. I meant that you could bore to the xr200r stock piston size and still have a couple of over bores left. Just to increase overall life. Max overbore would be unchanged as far as I can know.

 

 

Ok, I'm following you.  I'm honestly not up on the other stock bore sizes on the ATC'S.  Do you happen to know what year and model your cyl is?

 

Old School Al

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So that would mean that the sleeve is a lot thicker as well as the fins are larger.

So with that in mind. The cases might be bored out larger to accept the larger sleeve?

Or is it just the ATC cases and cylinder fins larger but the M/C cases are not?

 

 

Everything I'm aware of uses the same size sleeve OD with both large and small fin cyls..  If someone is aware of different, please correct me.

 

Old School Al

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Everything I'm aware of uses the same size sleeve OD with both large and small fin cyls.. If someone is aware of different, please correct me.

Old School Al

That's what I suspect also...

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Re OSA, I think it's the 83-85 atc cyl.

Re OP, here are some pics of the head on my buddies cr/xr hybrid that is from an atc I believe.ImageUploadedByThumper Talk1400542209.324696.jpgImageUploadedByThumper Talk1400542220.307542.jpgImageUploadedByThumper Talk1400542231.124243.jpg

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Everything I'm aware of uses the same size sleeve OD with both large and small fin cyls..  If someone is aware of different, please correct me.

 

Old School Al

 

Also my experience.

 

There seems to be two different cylinders sold on ebay, both with 192cc cast on the aft side; one has standard size fins and one has large fins. Might be the difference between ATC200 and ATC200X, so be careful if you want the large fin cylinder. IMO I don't think you need the large fins unless you race, run 218cc, or do a lot of slow speed  mountain technical riding.  

And they all fit the XR200 cases, including the XR185 cylinders. And can be overbored the same because the overbore limit is the machined OD of the sleeve that fits into the cases..

Edited by Chuck.

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thanx i will b searching for one for my winter project...

are there different large fins or are they all the same

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I missed this:

correct me if I am wrong OSA, but I think the 192cc cyl piston is slightly smaller than the 195cc cyl. I meant that you could bore to the xr200r stock piston size and still have a couple of over bores left. Just to increase overall life. Max overbore would be unchanged as far as I can know.

 

Honda uses a variety of casting marks for the the same size engine(s). The displacement mark cast into the cylinder has little if any relationship to engine bore size, it is a mark that I believe is required by the taxing laws in some countries.  It does however help ID which engine the cylinder was used on. 

 

From my incomplete notes:

 

Early XR200R has 195 cm3 on cylinder;
88-02 XR200R has 194 cm3 on cylinder, (same part number also used on 80-82 XR200 twin shock)
XR185 has 180 cm3 on cylinder.
ATC200X has 192 cm3 on cylinder (both big fin and std fin
Bottom of stock liner ODs ranged from 69.55 to 69.8mm

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Chuck, I see your point. However the research I did into the atc200x showed that it used a 65mm piston instead of the 65.5 of the xr200.

Edited by chadzu

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