ZX9R
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Billet Stroker ZX12 Cranks - 2008/01/09 16:58
Hi I am putting this up to see if there is any expresions of interst from other people for this item.
Currently in the manufacturing stage is a small batch of custom billet stroker crankshafts, to suit the Kawasaki ZX12 R motor, years 2000 onwards.
These will have a stroke of 61.7mm, which is a 6.3mm increase on standard, and will be available with the starter gear for street applications or without for racing only use.
The final weight for this version has ended up at 9,6kg.
The "race" version will be lighter by about 0,4kg, at 9.2kg finished. Considering its a much longer stroke and is balanced to a 50% balance factor the race crank is 38% lighter than original.
These are being manufactured in Europe by a well credentialed engineering company that specializes in this field. As you would expect the crank will be manufactured from a high strength steel alloy.
The crankshaft material to be used is Corus 722M24, this is commonly known in the U.K. as EN40B in old money, however the Corus material is more refined. Core strength in "U" to "V" condition is 63-75 ton UTS. The finished crank is gas nitrided for 90-100hrs, and will have a surface hardness of 52 HRC min.
This stroke will increase the capacity of a standard Kawasaki ZX12 R engine to 1335cc.
If an bored barrel is used, at 85mm bore, the stroker will yield 1400cc.
If a big block with a bore of 86mm is used with the stroker crank a capacity of 1434cc will result.
An aluminium barrel spacer plate will also be available, typically at 3.0mm thickness.
Other spacer thicknesses available to order.
Engine capacity reference with stoker crankshaft;
61.7 x 83 = 1335
61.7 x 85 = 1400
61.7 x 86 = 1434
Accurate cost is yet to be finalized, but it will be in the $4000 AUD to $4800 AUD range, with the race only crank being cheaper as it does not run the starter gear and balance shaft.
cheers
Darrin
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