trdfreak03

Hey everyone,

This is my first posting , I hope i can get some valuable help from you guys. I've recently purchased a gx35 motor and am looking to do the piston mod. I am using the engine on my motorbike ... I Would like to know some more info for those who have done the mod, or anyone who can give suggestions. I have a piston that i can use as a ginny pig to make sure that the new one i order is dremeld out the same as the the first one. Do i shave out holes for the valves only ? or do i have to shave .024" off the entire top of the piston?

This topic explained more in this posting http://www.rcuniverse.com/forum/m_4395766/tm.htm

First of .. a gx31 piston.. my friend damaged while taking it out of a motor... so it will be my test piston for this project



Here are some videos of my bike in action when i had my 2 stroke on it

http://youtube.com/watch?v=wxlDjj6zi...=motorbike%202
http://youtube.com/watch?v=KOS6vZlSIbA&search=motorbike


This is my bike with my 2 stroke motor


Please if anyone has pictures or anything please post.

thanks in advance
Steve

davewallace

My Feedback: (29)

trdfreak03,
First if you put a period at the end of a link, it doesn't work. You need to determine a couple things, before you modify a GX31 piston. How much clearence does the piston have between it and the squish band at top dead center? Do the valves enter the piston swept area? If so, how far? If not, how close do they come to the piston? The squish band clearance can be determined by inserting a lenght of 3/32" solder into plug hole and against the wall. Turn the engine over and the piston will flatten the end to the thickness of the clearance. Place modeling clay on the top of the piston and turn the engine over a couple times. disassemble and the valve clearance will be revealed by impressions in the clay. When you had the engine apart it would be a good time to check the difference in hight above the wrist pin beween the two pistons. Also remember that the piston skirt must clear the crank counter weights. If you know the squish band clearance and the piston hights, you will see how much you need to remove from the GX31 piston, if any. Most people allow no less then 20 thousands clearance in most engines. The piston to valve clearance needs to be considered also. Notch the piston for valve clearance if needed. Once you have the dimensions, you can do many things, such as cutting down the squish band rather then the piston for more compression. Don't forget the valve clearance.

Dave