Trying to help a mate with a Fireblade engined Westfield

You lads Know your Bike engines so thought i'd ask here for Help

He's Fitted Dyna coils to His Fireblade engine and although they seem to be performing well
He's getting strange readings from the Tacho
The Tacho' ain't reading accurately

I thought maybe interference of some kind ?


He Re-fitted the old coils back and the problem went away

Any ideas lads ??


Cheers
Perksy

Just for the Record incase anybody else has this problem
The Answer is to seperate the coils and make sure they ain't too close together