2 stroke custom build! Need help with head!

Feb 3, 2021
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I have cut the top off a yd100 jug, and severely modified the ports And case for the build. Using a minarelli jog head i cut to match at the moment as a test subject. Way to small for heat dissipation. 50m bolt pattern on the yd100 and the miniarelli head. I have never owned a 66cc or 80cc motor kit. Is the bolt pattern 50mm center on those for studs? Or 48mm? So many conflicting ramblings. I found few cnc heads i want to harvest and recut for this project for 66cc/80cc but before i go wasting 55$ on a head with bolts way to close "48mm" to my cylinder walls i figure i would ask! If not does anyone know a thick head with 50mm spacing? Cuttable material wise*
 

Larry Trotter

Active Member
Nov 26, 2017
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I have a 66cc head here and tomorrow afternoon I will have a 50cc head to compare. I intended to put the 50cc head on my 66 for an increase in compression ratio. Tomorrow I can tell you. The 50cc head cost me $7.00 with a head gasket delivered on eBay.
 

Larry Trotter

Active Member
Nov 26, 2017
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OK. A 66/80cc is 45mm center to center as is the 50cc head. Guess it doesn’t mean they are all the same.