I am calculating the compression ratio and need this figure. I know what the figure represents but do not know the amount. I can't seem to find it.

 

Brian,

I believe it's 83mm bore, and 70mm stroke. Hopefully somebody else can confirm.

-Josh

 

Piranha,

You are correct sir, YES! An 83mm bore by a 70mm stroke.

 

My goodness...

Miracles never cease [img]i/expressions/face-icon-small-happy.gif[/img]

-Josh

 

Hey Brian,

just in case you need it, the 83mm bore converts over to 3.2677". The 70mm stroke converts over to 2.7559". Straight from the Polaris manual.

KT

 

P.S. you'll need a thick, and perfectly flat piece of plastic, or glass. Some grease, to make it seal. A science lab buret, and some water. These items are for CC'ing your cylinder head. Remember to install a sparkplug, to duplicate it's intrusion into the chamber. Seal the edge of the head with a thin film of grease. Place the glass or plastic ( with one each hole drilled) over the head. Proceed to slowly fill the chamber to accurately measure it's cc's.

KT

 

A 50cc syringe will substitue for a buret. You can get them from a hobby store that sells R/C model cars and aircraft ( from SIG ) or from a veterenarian or feed store if you're not in a larger city.

 

I ended up using a childrens medication 10ml syringe. It worked great. I tried something out of the blue: I installed two head gaskets which brought down my compression to a more suitable point. (155psi) I will run 100 octane fuel and see how she runs. Hopefully this will work.[img]i/expressions/face-icon-small-confused.gif[/img]

 

its a two - stroke!!!!!!!!! Thats why you mix the gas and oil for lubriction. if you need any more help just let me know. Im just being a smart a@@

 

Why dont you buy the billet head with the dome for the kind of gas you want to run? You wont have to go through all the fuss and worrry about gas plus it cools better.