I purchased my first motorbike today, it's a used a honda CBR125 2012 model. After about 30 miles of riding the speedometer started jumping up and down and showing speeds between 0 - 150mph, i was travelling at about 30mph. There are no other obvious issues to comment on. After a further 5 or so miles it self corrected and began showing what i would estimate to be the correct speed.

Do you know what might be causing this and if it's something a novice would be able to fix at home? I haven't been able to find a solution to this problem online and was hoping someone would be able to help me, otherwise it's a trip to the shop. Thanks!

 

Welcome aboard. I'd probably start with a visual of the speedo wires (I don't know that model, but I think it's up on the front wheel)

Make sure it's tight and nothing obviously wrong with it. Ditto for where it connects up at the gauge cluster. Unplug it and give it a visual to make sure nothing's burnt. It's not a super cheap part, but still less expensive than a couple hours at the shop

Any other trouble with the bike?