I need help -- GS 160 motor/top end only converted to SS180 top end

About 10 years ago I was looking to get more power from my 1963 Mark II GS 160. I bought everything I was told that I would need from a scooter shop in San Francisco, CA. Ever since this conversion, my scooter has never ran right or for very long. I have now narrowed it down a couple of issues that were my fault and need to know if there is anything else I am missing or if anyone has recommendations for me to finally get it done right. I've tried to get support from the shop that sold me all the parts, but they haven't been much help.

I initially purchased an SS 180 crankshaft, piston/rings and was told my original GS clutch would work fine. The shop failed to mention that my original GS flywheel wouldn't work on an SS 180 crank or that I needed the flywheel side cam for the ignition to work. I had to figure it out on my own later. Once I was able to get the scoot running, it would run for awhile and then not start again. The clutch never seemed to fully disengage (pulling in the clutch lever) and when I did, the engine would slow down and then stall. It would not always start again after that happened. It got to a point that it would start at all, so I threw a cover on it and parked it for several years.

I recently started trying to problem-solve my issues. Thanks to SIP and all the original diagrams, I located a part that I don't ever recall my GS having, the concave washer/spacer that goes before the clutch on the crank. I got excited thinking this may be the main problem, until I took my clutch apart and flywheel off. My plain plates had turned blue and my back plate due to what must have been a significant amount of heat. Furthermore my stater and flywheel were full of case shavings!

This brings me to the present. I am currently getting ready to place an order with SIP for several parts including:

--Washer SIP clutch, for Vespa 160 GS/180 SS 

--Bearing Clutch Baseplate for Vespa 150 GS/160 GS/180 SS, 24x28x17 mm Weight: 0.014 kg


--wood ruff keys

There are many options as far as clutch plates go. I'm needing to know if I should get the clutch for GS: SIP part # 93065000 or the SS180: SIP part # 93063000. There is a small variance between their thicknesses, but considering the problems I've had with my clutch and the slop in my crank, I need to know what would be best. If I am missing anything else or you can recommend something to help me, I would very much appreciate it. Thanking you in advance!


Brandon O'Neil

Bakersfield, CA, USA