Scooterotica

I have an early SIP digital speedo fitted to my GP, it generally worked very well however in the last few weeks it will start off working ok then whilst riding the needle will rise to the 12000 rpm mark and the speedo will read 124MPH for a while before going blank.
I do have a resistor plug and cap fitted and as I say it worked perfectly well up until the last couple of weeks.

Any idea what is causing it? do I need a new one?

Cheers Andy

Same happened to mine recently and I replaced it.
..when I removed the old one I did notice that some of the earth wire threads were broken so worth checking. I've no idea if this caused the problem., I sold the old one and the guy that bought it did say there was a battery in the speedo but was a basta rd to get to. Buy a new one in the UK they're similar price.

Mine was a pig for doing that until i took out the NGK resistor plug and replaced it witha champion NR2C, Never done it again since.....

Thanks for the replies, I will try a new plug before buying a new speedo. You never it may be the problem and a cheap solution!