hey guys, what kind of cc's are we talking about? from what I've read a 250r with big bore kit is 72.00 mm, makes it a 295 cc. Is this right? So what is a 77.44 mm? thanks Joe
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hey guys, what kind of cc's are we talking about? from what I've read a 250r with big bore kit is 72.00 mm, makes it a 295 cc. Is this right? So what is a 77.44 mm? thanks Joe
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what year R? 77.44mm Bore? or 76.44mm bore? your post includes both....
Last edited by cr480r; 12-25-2007 at 10:45 AM.
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An air cooled is 295.3cc with 76.44 bore.... a water pumper is 330cc with that same bore
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You have to include the stroke of the engine into the equation.The aircooler stock has a 64.4mm stroke and a 70mm piston it takes a 76mm piston to get 300cc out of the motor without stroking the crank. The 85 R had a 66.0mm bore and a 72mm stroke so therefore you may get a 295 out of that with a 72mm piston.
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sorry guys, it's early, it's a 84 250r with a big bore kit. with a 76.44 mm piston.
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so you didnt know you had a 300 kit huh.. that like getting a present right there..good luck on it .. these guys will point you in the right direction!Originally Posted by yellowbeard
it would be better for you and us if you could keep all your post's in one thred
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will do, just i'm new to dealing with the big bore kit. will try to keep my questions to a min. and all in one thread. real interesting, thanks for the info. Joe
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NO NO Please ask your question's these guys will answer!!
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Questions are good... post as many Q's as you want...I think what Raffa means is try not to post multiple threads on similar topics and search to see if a topic has already be covered before starting a new one... Old threads can easily be revived by adding a new question that relates to the topic..
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I Think SYKO has some info on the Air Cooled Thing's as well .. Raffa .. you have one of those ATC's also ?
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Nope.. I built one for Bruce's ice racer...Mr hondaline had the parts on the shelf for his particular build..I really hope to see it on the ice this year..
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yep you are right, 295.3907 etc.....
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hey guys, 1upfront has it posted ^ that 72mm = 295cc. what I'm looking at is 76.44. So, if 72mm is 295cc what is 76.44? Joe
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ok re-read cr480's post said that 76.44 is 295cc. been reading up on all the old threads about the big bore kit. still have no idea what ya'll mean by decking the cylinder. my cylinder, shouldn't it be already decked since it has had a 76.44 mm piston already.
Last edited by yellowbeard; 12-25-2007 at 08:55 PM.
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Well by the sounds of it the new replacement piston is a bit different from the original... So even though the bore size is the same as your old piston, the piston height is not... The deck height is the distance from the top to the bottom of the cylinder... So since the distance from the piston pin to the top of the new piston is reduced the cylinder deck height would need to be reduced the same amount for the piston to reach the top of the bore at tdc again.
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