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| cr250 rings https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=2944 |
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| Author: | crcraig [ Wed Feb 02, 2011 8:57 pm ] |
| Post subject: | cr250 rings |
I am ready to reassemble motor on my 79 cr250 I ordered Wiseco top end there are 2 rings available cd & cdm for chrome bore this cylinder had 70mm piston in it but there was head damage from motor failure at some point before I got bike. My question is what rings to use as the cylinder walls are good so it must have been replated or replaced ? I read not to use the cdm rings on nikasil cylinder how do I determine whether this is a chrome or nikasil cylinder |
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| Author: | osu_cowboy [ Wed Feb 02, 2011 11:45 pm ] |
| Post subject: | Re: cr250 rings |
Home remedy - you can tell an iron liner from a chrome bore with a magnet. Take a small magnet and slide it carefully along the bore. If it sticks, it's iron. Or you can take it to your local shop and they can tell you what it is. |
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| Author: | crcraig [ Thu Feb 03, 2011 5:02 am ] |
| Post subject: | Re: cr250 rings |
the cylinder has not been sleeved will a magnet stick to either chrome or nikasil ? |
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| Author: | b-joe [ Thu Feb 03, 2011 10:09 am ] |
| Post subject: | Re: cr250 rings |
crcraig wrote: will a magnet stick to either chrome or nikasil ? no. |
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| Author: | FTE [ Thu Feb 03, 2011 12:37 pm ] |
| Post subject: | Re: cr250 rings |
I believe the Wiseco's come standard with a chrome ring that is not to be used with the chrome bore; you need the other ring for the orginal chrome bore. The bikes came stock with chrome bores. It would have to have been replated if it was nikasiled. It's highly probable that any worn cylinder that hasn't had a steel sleeve put in is chrome. If the piston that came out is an oem one as well, that would make it even more probable it's the stock chrome bore. My understanding is that if you have them nikasiled, it doesn't matter which of the ring types you use. The replating services allow you to use aftermarket or NOS oem kits, they just want to know which because the tolerances are different. I think the rub for your case, then, is that whether it's chrome or nikasiled, you can use the ring designated for the chrome bore. If you know that it has been replated, then you will know it's not a chrome bore. Nikasiling is better and I don't think anyone does replates in chrome. Certainly it wouldn't be customary. I don't know how to tell the difference because I've never seen a worn original chrome bore side by side with a worn nikasiled bore. The NOS chrome bores that I've seen look more silver than the nikasils I've seen. You might shoot Millienium Techologies, one of the better replating services, an email and see if they have any input. |
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