My son has a 50 cc Eton (1999 model I believe), and it is time for a little more power. I was wondering if a 90 cc jug, piston etc. would fit his engine? Is the stroke the same on these two engines and rod size, length? Also what other parts will interchange? I also need to change (find a place to buy) his sprocket ratio, we have put taller, wider tires than stock on his bike and take off is not the greatest now. My son doesn't race his quad, just rides some trails and he loves the mud.

Now to tell what we have done so far: honed cylinder, new rings, removed baffle from muffler, removed oil injection, drilled main jet-rebuilt carb, matched exhaust port to muffler, free rev cdi box, milled .050 from cylinder head.

With winter coming on and not too much riding 'till spring I am planning for us to gain some more knowledge with his bike instead of going out and buying a bigger quad right now. I'd like to teach him how to use his mind and his hands to gain what he needs instead of just buying a new bike to gain some more power.
Any help is much appreciated!

 

Don't think a 90cc will bolt on, but Billy Holt at WRH Racing has a 70cc kit that will make that sucker scoot! You might pm mxmike about it. His kid uses one.


wrh

 

Different engines. You can pull that engine you have up to a 70 very easy and get a lot of power out of it. Change the pipe first. It really will make alot of change.

 

Thanks guys!
I will look into the 70cc kit and a pipe. Any brand pipes better than others? will I have to modify the clutch too? Also, where can I find some sprockets to lower his gear ratio a little?

 

Yea Id say get a good pipe. Then a good carb and filter. That set up will make it alittle faster than stock 90's. A good 70 kit will make it smoke a stock 90. Its not even close.

 

We like the WRH pipe. It will need a clutch kit for any good pipe. They should come with the pipe.

 

If you dont mind I wanted to ask you a few things about eton mods. I heard your the man. My son has a 99 eton 50 with a 70cc kit on it. The kit has been on since 2000. I just replaced piston and rings. I hear that these things really rip withthis kit but this one doesn't. It is faster than the 50 but not by much. The kit I got years ago came with a cheesy pipe also. Is that part of the problem? I am alittle short on money right now but my son is 9 and wants more out of it. It still has the stock carb, and stock clutch. Nothing else has been replaced. I was also wondering if the belt needs to be replaced. It doesn't have much get up and go. The compression is good. Any idea's?

 

The pipe and clutching should come as a package.If you get a whole package from someone it makes it much easier to get parts that all work together.