Suzuki 2 Strokes

I found the below gauge on Ebay, listing a 5 to 1 ratio. Does anyone know if 5 to 1 will work ok on GT500 ??

http://www.ebay.com.au/itm/201414894901 ... EBIDX%3AIT" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Appreciate any help

Thanks Trevor

Unless I am mistaken I believe most all Suzuki's of that era were 4:1. If you can, look at the drive tang where the cable hooks up. Make a mark on the wheel and rotate it 360 and count the revolutions of the drive tang.