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| big bore 1973/74 cr250 https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=3978 |
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| Author: | jimg1au [ Tue Mar 05, 2013 5:35 am ] |
| Post subject: | big bore 1973/74 cr250 |
hi is there a way of making a big bore cr250m 73/74.i bought a set of cases on ebay and they have been machined out to take a bigger sleve.is there a way of making a 1973/4 cr300m jim |
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| Author: | Dave [ Tue Mar 05, 2013 9:41 am ] |
| Post subject: | Re: big bore 1973/74 cr250 |
you may need to find this out for yourself unless you can locate a aftermarket cylinder from the early 70's that allows the bigger piston to be installed. they made such kits for say a Yamaha DT1 that allows the piston for a RT1 with it's 80 mm bore to be installed that took it to 322 cc's. then there is the question of rod lengths and the Bore and Stroke ratio itself. the rod length question would be a decisive factor on what piston to use. |
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| Author: | rayivers [ Tue Mar 05, 2013 11:26 am ] |
| Post subject: | Re: big bore 1973/74 cr250 |
I wonder if an FL350 piston etc. might work: http://www.partzilla.com/parts/search/H ... parts.html Wiseco might also have something, maybe from a piston-port snowmobile motor. Ray |
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| Author: | ohiomotoxer [ Tue Mar 05, 2013 5:52 pm ] |
| Post subject: | Re: big bore 1973/74 cr250 |
ummm why? the poor old elsie is barely good enough at 250cc why would you want to up that? Yes I raced one and I can attest to ALL of its flaws. I used to go through cranks on my 250 as much as my 125... THEN I switched to a hoosk and all I ever did to it was put gas in the tank. IF you are dead set on trying it contact wiseco they can give you all the data on pin size, timing edge and pinning. good luck |
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