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cr250 78-79 https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=683 |
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Author: | 2five0 [ Sun Jun 12, 2005 9:42 am ] |
Post subject: | cr250 78-79 |
will a topend off of a 79 work on a 78 bottom end. thanks |
Author: | redrocket190 [ Sun Jun 12, 2005 3:34 pm ] |
Post subject: | |
Yes. Check that the piston you use is drilled to lubricate the exhaust port bridge introduced with the 1979 cylinder. |
Author: | 2five0 [ Sun Jun 12, 2005 8:10 pm ] |
Post subject: | |
if i have a nos honda piston why would they make you drill the holes. thanks |
Author: | redrocket190 [ Sun Jun 12, 2005 9:30 pm ] |
Post subject: | |
Wiseco recommends some oil lubrication holes for the 1979 cylinder because of the exhaust port bridge which wasn't present in 1978. Honda however offers the same part # piston for both 1978 and 1979 (13100-430-000), so I assume both don't have holes. I use the former, hence the advice. |
Author: | william richard [ Sun Jun 12, 2005 10:18 pm ] |
Post subject: | |
every 78 CR250R ive owned had a bridged exhaust port-the port that is different is the intake port-it has a bridge crossways in the middle of the main intake port not present on 78 CR250R cylinders-if there is something different i havent seen it-anywho the drilled skirt is a good idea on any bridged exhaust port |
Author: | redrocket190 [ Mon Jun 13, 2005 1:33 pm ] |
Post subject: | |
Thanks for clearing this up (and the pictures you sent). I have cylinders with and without intake port bridges. Now I know that they are 1979 and 1978 respectively. I am sure that at one time I had a cylinder with an un-bridged exhaust port, but I let that one go with a parts bike so I can't check. I wonder if some clown ground the bridge out in a "porting" job? Or perhaps I am losing it ![]() |
Author: | 2five0 [ Mon Jun 13, 2005 5:00 pm ] |
Post subject: | |
i can tell you one thing i am not drilling holes in my piston. |
Author: | redrocket190 [ Mon Jun 13, 2005 10:16 pm ] |
Post subject: | |
And there lies the difference between well-intended advice and an instruction. |
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