Thanks mark and blue and all others that contributed. I have the 150 MPH speedo so I should and do have the 15/12 gearbox, therefore if it is reading low, it has to be the speedo head that needs attention as I have the new gearbox and new speedo cable. I had read a post here on the forum that indicated that 70 MPH at 4,200 RPM was what they registered and thought (incorrectly?) it might hold true for all twins (mine was indicating 55 MPH at that RPM). As I noted in previous a post, my manual said the gearbox ratio should be 2/1 but I have found other "misinformation" in it so wasn't sure. Since I thought the speedo was reading lower than it actually was due to the 70 at 4200 info and the ratio wasn't what the book called for (two bits of erronious info), I thought mine was way off and started my "wild goose chase". I have since taken the speedo off and shot a small squirt of a silicon lube into the spigot where the cable goes in. The indicated speed came up a little and now it reads between 55 and 60 MPH at 4,000 RPM. The needle does wiggle a bit so I'm thinking the head probably needs a going over by a pro. I'll probably contact the people GPZ recommended few posts earlier. (thanks GPZ, and you sent the right part, sorry about the mess)