I am wondering if anyone can tell me what the letters "HU" stamped into the Heads on my 906 are for, i noticed them the other day when i was fiting new Coils and thought that they may have been stamped by the previous owner but then i was having a look at EBay Paso parts and here is a pair of 907 Heads in the USA and in the picture can be clearly seen the "HU" stamping as well, just curious.

Thanks
Harry

just a stab in the dark, My guess would be it identifies the foundry wherer the heads got cast

There is also a letter 'B' stamped on the top fin of my 907 heads. On the carb Monster 750 models the heads marked 'V2' were the ones to have, those marked 'W' had smaller inlet valves. It may indicate that the heads have the sliding clip to enable the inlet rocker to slide along for access to the shims even though these heads got the gold valve covers.