That 47 rear sprocket is the biggest reason it’s off. Probably to turn that heavy tire combo u got back there lol
If it has a jackshaft, those sprockets are probably the same size and don’t factor. The front sprocket behind the clutch slave master is the one u want to check.
Speedo healer is all u need.
I've run 190 and 200 on my Gen2 and that seems to just about correct the stock speedo which reads high with the smaller stock tire. ...so maybe there is more to it than the 300 tire. If anything, a larger tire should make the speedo read slower. +25 mph at an actual 80 does seem like a lot even with a stock tire. A Speedohealer will take care of it but I'd want to find out what's causing such a large discrepancy. If the rear sprocket is stock size, I'd almost bet the front isn't.
You have a clutch slave cylinder and a sprocket cover to remove. Proceed with caution, the clutch slave might need some extra preocedures to prevent it from popping out while removed from the pushrod. ...also, torquing the clutch slave bolts, lots of sprocket covers have cracked so be careful. I believe it's just one bolt that's the culprit. I wish I had a tutorial thread I could point you to. I started a sprocket cover tutorial years back but never got around to finishing and posting it yet. I found plenty of info on sprocket cover removal on here though so take your time and ask questions. OH--aligning the sprocket cover to the dowel pins is another thing I remember requiring extra care. I wouldn't expect this to be a one day job if you've never done it. LOL if you search, you'll probably come across threads I asked questions on.
It’s a SPR520-47T sprocket on the rear. The sprockets between the transmission and rear sprocket are both 18 tooth. No clue what the sprocket is on the transmission. The tire is a 300/35R18, not sure what factory is supposed to be.
The front tire is a 120/60ZR17 55W. Haven’t had a chance to look at what the front sprocket is yet, spent the last 2 days riding and crashed when I got home.