What is my speedo ratio?

I have a 79 KZ650 but I want to switch to a 16 inch rear wheel & a 19 inch front. So what would my speedo ratio be? Would it be the same for tach as well? Doesn't changing the wheel size change the ratio?

if your front wheel is already 19" it shouldnt affect it too much,thats where your speedometer runs from.tach is run off of motor tire size will not affect it.:whistle: goodluck,happy wrenching!

Ok so what is the ratio then?

im not sure of the exact ratio;)

Ok well how do I know what speedo to get? Does anyone know what the ratio is?

you should be able to use a tach and speedo off a 650,900 0r thousand up to 1980 i believe.do ya need one?

Well actually I want to buy a completely different speedo/ tach for it. Something from JP Cycles for example. I just need to know what ratio to get. Does anyone here know this? Surely someone must have installed one of these on their KZ650 with a 19 inch front & 16 on back...

I would suggest that you contact some one like JP Cycles (?). Tell them the size wheel you will be running. They, most likely, can tell you what you need.

That is a good answer. I will just wait until I have the wheels I am using & then call them & ask. Thanx guys!

if you would have brought up the fact you want to install aftermarket gauges from the start that would have been very helpfull.no biggy;) goodluck,happy wrenching!

You can figure it out by counting the turns of your tach cable to one turn of the engine ,, I know sounds kinda hard to do .. I ran into this with my Honda a few weeks ago ,, They sent what They thought I needed ,, it was a 1-7 tach I really needed a 1-5 tach ,, how does this work ? one turn of the tach cable , The tach will read 5 RPMs . one turn of the tach cable will read 7 rpms. as you go up the scale say 1000 turns of the tach cable 5000 on the tach so the difference between a 1-5 and a 1-7 ,, is ?? Well it multiplies as you go up the tach RPMS 1000 tach cable RPMS = 5000 1-5 , 1000 tach cable rpms 7000 1-7 so in the beginning it was only 2 rpm off but at the end it is 2000 rpm off ... I am so confused now ,, so I know you are too ...

Try doing a search both here and in the Archives, I'm reasonably certain that I saw that info posted here in the past.