Aftermarket CR250R cylinder?

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7/7/2020 6:58 AM

Can anyone identify this oversize cylinder on a 1980 CR250R? It does not have any markings on the exterior of the casting of any kind, not even the number of CC's. The fins have 45 degree corners like Mugen uses quite a bit but most of their cylinders have raised cast ID on them. I researched ATC250R and FL250-350 Odessy cylinders but did not find them to be similar. This is the center port model. Thanks for any help. Photo


7/7/2020 8:26 AM

Definitely following. How about the HRC 300 cylinder for the Honda ATC? I thought those had specific heads though with one more stud but I could be wrong on that.


7/7/2020 8:48 AM

Thanks for the response. Yes, there seems to be various versions of head bolt arrangements for the ATC and FL over the years.
I'll see if I can find anything on the HRC 300 cylinder.


7/7/2020 3:33 PM

What’s the bore measure out at?


7/7/2020 7:06 PM

I haven't opened it up yet. It is a running motor in a rideable chassis so I'm trying to figure out if the cylinder is special or just mismatched OEM parts before I put any time or money into disassembly and reassembly. I know, I'm cheap and lazy.


7/26/2020 4:58 AM

im interested in the cylinder if you decide to sell fits my atc honda! ive been looking for a long time for such a cylinder..hard to find here in europe ..almost no atc's over here! cheers henry


7/27/2020 6:35 AM

I guess you have to take the cylinder of to see what you have.
Maby ATC250 cylinder have smaller cooling finns then CR250, and you have ATC head?

FL350, Mugen and "Hondaline 300"(HRC?) have 7 bolts to the head if i remember correct.


7/27/2020 6:43 AM

Left FL350 and ATC250 to the right

FL350 head compared to CR480


7/31/2020 8:24 PM

Hi all,

Thanks for your input, I ended up selling the bike without being sure of what it was.
Sincere apologies to henryhilco as I would have liked to help him. I had been called away to other responsibilities for a while.