If i make the front sprocket 19 and the rear 25 and get the rev limiter will i get into the 50s? Also where can i get the sprockets and the cdi?

 

I was looking on www.miniquadracing.com and the site had eton 18 front sprockets and 25 rear could i use those sprockets on my 2 stroke polaris sportman 90?

 

On the predator 90 do you know how much the head can be plane off and still use premium gas. it currently is stock using premium gas and Klotz oil at 40:1(gas to oil). the carb has been adjusted (fuel/air) for proper burn, fan off the flywheel, disconnected the injector pump and removed plastic off the head. Thanks for the info.
later
hunt

 

KY,

You have to go down enough to get the double hump out. Plus you need the angle of the piston, The metal thickness will be questionable at tha t point. I would suggest buying one tha twas milled for compression. Put the plastic and your fan back on before you blow this thing up. If you are worried about fan load, buy a 10k rpm fan.

 

Yes, i was needing to know how many thousandths to have milled off the head only and still be able to run premium gas. Do you think the fan on the flywheel produces enough air flow that without it you could burn the engine up. We have been trail riding and racing the past month with the fan off and the plastic around the cylinder off. thanks for your help.
later
hunt

 

Hunt,
I don't mean to sound ugly but you are more than welcome to buy one and measure it for yourself. If you up the compression and do not run the fan and shroud, you will lock it up. I guarentee.

 

Trextommy, Thanks for the input, i'll put the fan and cover back on. Has anyone else shaved/milled the cylinder head cover on there 90's or does anyone know the distance i must have from the piston top to the tip of the spark plug the area/volume of the cone that it could be without having to go to race fuel. Thanks again for any input.
later
hunt

 

i really dont think you will get 50mph out of a 90cc quad. 40mph is pushing it

 

Trextommey said if i put a 19 tooth sprocket in the front and a 25 - 27 tooth sprocket in the rear and get a performance CDI i would be doing around 45 - 50 mph

 

You can get even more than that, The Predator tranny lends itself to gear ratio's that promote acceleration there are other quads that give up acceleration for top speed, Transmission ratio wise, and therefore can run smaller diameter tires 16 6.50 x 8.