Contact huztl they have been very good to me they shipped me a cylinder that wasn't tapped for the decomp.i emailed them sent photos to another address they requested they sent me two pistons and another cylinder another order they sent the wrong part's and are sending me another order right now.
Only downside is waiting sometimes over two weeks.
Although I ordered via UK eBay (machinerypartsstore) I suspect it's the same huztl outfit in Hong Kong. In any case I received a very apologetic email from the seller for the mistake and say that they have already dispatched the replacement cylinder. I can't fault their customer service so far and hopefully in 2 weeks or so I should be all sorted.... fingers crossed.