They are supposed to have a tci shut down at 180... According to Newcastle Motorcycle Dr. When the speedo hits 180 it is meant to shut down spark, then your speed will drop and spark resumes... I presume it would feel like a missfire at high RPM... not sure how it works, I have a spare cluster, might look further into it...
I'll have a look this weekend, there's 4 other bikes parked up in front of her at the moment. There's a thread on here somewhere about the speedo related restriction & I think it was difficult to get around. Obviously this thing isn't restricted but I know nothing about if any work was done on her to de restrict it. By the looks & condition of her when we got it, it had been very well cared for in her life before it got into the hands of the last owner or maybe last 2 owners, she's all in good honest condition & straight, she was just in neglected condition from sitting un covered in the weather for a few years, maybe just a year. She has a new engine hence the 91 model in an 89 frame. We got her just in time. A new set of fairings & a good wash, carby rebuild, oil & filter & a battery & away she went. She'll undrego a complete nut & bolt rebuild when the kids are finished, engine & all.