IIRC, but I could be wrong, Jojje has has said that the Speedmaster rev limiter is at something like 7,900 or 8,000 rpm from the factory. Now your tach needle isn't necessarily going to reflect that, but that's what Jojje says it reads out as on his computer, and the results from dyno testing of some of our members.
Whichever way my sometimes faulty memory might end up on this subject, my point is you might want to ask him about this before you send off your black box. Because IMO, if we are getting 8,000 rpm out of our Speedmasters, I don't see any need for getting anymore out of it unless you've thrown in some Wiseco forged pistons. I wouldn't want to take my stock motor above 8,500 rpm, but that's just me. Now if you're at 7,400 rpm like on an America or regular Bonnie, then a 1,000 rpm boost might be justified.
Now all this is just my opinion: I don't want to take any chances on the possibility of decreasing the reliability of my bike, not to mention voiding the warranty with raising the rev limiter. OTOH, I don't criticize people for doing whatever they want to the bikes they own. So if you still want to get it done, more power to you. Just make sure you report back here with the results, because it always makes for an interesting read.
