Vintage Dirt Bike Q & A

I picked up a ATC250 cylinder head and barrel, and I noticed that it does not have the 2 head locating dowels that my 78 and 80 heads have. I want to put it on a 1980 bottom end, should I machine the dowel holes or not worry about it? I guess honda felt they were not needed in the ATC motor, but added the rubber dampers in the fins.

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Update: I took a closer looking at the ports and they do not match the CR250 ports on my 78 and 80 cylinders, much smaller in size. I guess the ATC was sold with a milder tune, so I am scrapping the idea of putting this head on my 80 cases.
Is there anyone out there who has ridden one (ATC250R) to compare what type of hit this one had compared to a CR?

_________________
I have too many....
my wife thinks I should join motorcycles anonymous.......

i have had several atc's. there are large sand dunes here and if you don't have a dune machine you ain't sh+t. the air cooled atc 250s were mild on the power band just good smooth power all the way trying to get picture of my dune ripper to come up

the atc250 has about 10hp less than the cr250.

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80 CR250Ra
80 CR250Ra
78 CR250R
80 CR80
82 Bultaco Sherpa 340
78 Bultaco Pursang 250 MK12
76 Bultaco Frontera 370 MK10
76 Bultaco Alpina 250
73 Bultaco Lobito 125 MK6
76 Suzuki RM125A
90 Kawasaki KX250