Replacement Pinasco Cylinder

Hi, I managed to seize  my Pinasco kit today.  My setup is:  Pinasco 177, 26mm si carb with a JL right hand stainless steel expansion.  The kit is just bolted on and the casing transfers are not matched to the kit.  I was running a Sito plus until a few months ago  and the kit has done about  7000 miles.  Carb settings are  125 main, BE4 mixer, 190air corrector and 50/120 idle jet.  Ignition timing is set at 20 degrees using an NGK8 plug.  My feeling is that my main jet should be larger as this setup worked fine with the Sito.  I had thought that the main jet was too large when using the Sito so didn’t increase the size of this when moving to the JL. The crown of the piston is completely unmarked, no holes but the piston has partly melted around the rings on the the side of the piston opposite the exhaust port and this has jammed the rings in place in this position.  Also. part of the plating has come off the bridge in the third transfer port and stuck to the piston so. it’s either a new barrel or a replate, bugger.

If anyone can offer any useful advice on jetting this would be helpful.

Also, does anyone know if I can buy a replacement barrel for the Pinasco kit?  I bought a new piston and rings a few weeks ago but as the cylinder is now damaged I need to replace this or get it replated.  I don’t really want to buy a whole new kit.  SIP don’t seem to sell the barrels only, just the whole kit.

Many thanks,


No direct experience with RH JL, but i have heard that people run with big jets, around abouts 130ish+. Start off at 135 and work your way down.