LCGB Forums

Running SIP Speedo DC with sensor cable

Standing still revving the engine, the click is all over the place but settles to zero on high revs.

When riding it around double the speed.

Any ideas?

https://streamable.com/3uu65m

Usually, this is electromagnetic interference from an unsuppressed ignition system.
If you are using an unsuppressed plug then you need to have a 5 kohm suppressed plug cap. One or the other, not both.
Just use a multimeter to check the resistance across the plug cap and similarly measure the plug to see if it has resistance.

Thanks.

I’ve been using the NGK red rubber cap which turns out to be a resister one (I didn’t know) so I’ll take the resister plug out, although I was trying with just an ordinary plug too.

I’ll get the multimeter out in the morning

Dont take it for granted that a red NGK plug cap is a resistive one. Thats a bit of a myth. You have to measure it to confirm.

Mine worked fine with non resistor plug and resisto cap but I then added a scootronics speedo and couldnt get the speedo on that to work. Had a word with Anthony Tambs and he said to use a resistor plug. Made the change and they both work fine. Having said that the Scootronics does drop out from time to time but I suspect thats a lose connection.

Plug cap was correct 5ohm.

B8ES reading 0.00

Worth trying a resistor version of the same plug but with a non-resistor cap

I use Denso plugs and a W24 ESR is equivalent to the NGK B8ES

Tried Colin

Bilko wrote:Tried Colin

You dont seem to be having much of that legendary Irish Luck Rob

None whatsoever!

Bilko wrote:None whatsoever!

But seriously, as FnF mentioned, NGK are often 'iffy'. Denso are a good make and dont get copied so definately worth a try but be careful as some types dont have remivable nipples on the top so the plug cap needs to be that type.