Last year I started to take an interest in upgrading my 79 GS1000EN engine which was already equipped with a tried & true Wiseco 1085 Kit with Andrews S1 Cams, VM29 S/B and a Supertrapp 4 into 1. Living in Colorado Springs at 6000 feet I have probably lost approximately 20% of my GS's HP & torque associated with with the Big Bore Kit.

What to do? My project goal was to boost street torque so I started reading old threads. I ran across Frankenzuki's thread about transplanting a GS1100G Head on top of a GS1000 2V engine and I that started me thinking. I didn't want to punch out the GS1000 sleeves because at 73mm they were already paper thin. Although there are old threads on the subject what I decided to swap the GS1000 Cylinders & Head and swap them out with the following:
  • GS1100G Cylinder and bore it out to accept a set of Wiseco 1100 pistons with a 10:25 to 1 CR
  • Top that off with a GS1100G D Port Head w 3 angle valve job & mild street port
  • Keep the Andrews S1 Cam which enhance low end punch
  • Swap the VM29 in favor of a rack of Mikuni RS34 Flatslides with K&N individual Air Filters
Unfortunately with all projects they take more time than expected coupled with the fact that sourcing the RS34 Carbs became a nightmare with the Japanese earthquake. Fortunately Z-1 came through in a pinch. So follow along as I document this project. I took over 125 pics from start to finish. First, I had to get the 1100G parts which I found on EBay back in late Novemeber . . . Here is those pics that I started with



Supposedly low mileage but corrision was evident by the intake port



Th head I removed was a S-1 model & this one is a S-6 ( last of the breed)


GS1100G Cylinder very beefy compared to GS1000 cylinders