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Old 08-19-2011, 08:18 PM   #40
crawler07 OP
Joined: Oct 2010
Oddometer: 60
Originally Posted by spo123 View Post
I think that IF you attempt to "modify" the ports into the nonport piston, you will have a NASTY surprise "down the road"!
IF you get the machine to run decently, a seizure and or severe vibration (unless triple beam scale balanced) will occur.
PERHAPS I am wrong......won't be the first time....
SPEND the $325 or so and get the correct rings and the correct piston.....get the cylinder bored to match the new piston and go for a ride.
Set the TIMING correctly......or be prepared for a seizure and another top end rebuild......I will not even mention CRANK SEALS and CORRECT carb settings!............Watch for air leaks, as well.
The 360 is a nice motor.......Do it correctly.
Why replace the piston?........Previous seize?..............Nasty bits can EASILY get into the lower end.......Ask my son!
Good luck and I honestly wish you the BEST OF LUCK!
Ride Fast and Safe!

Tank you for your opinion, but I have already had the cylinder bored out to fit the new piston so I think I will get this one to work. I dont see it giving me problems down the road,the piston with the ports in the skirt doesnt look any different aside fron the openings in the skirt. I looked on the inside for some type of ribbing that might have been added(for strengthening) to the piston that has the skirt openings and their isnt any and the solid skirted piston doesnt have them either. As for it having vibrations, have you ever ridden one of these? They have no counter balancer so their nasty little vibrating beasts to begin with. I only tore it down due to some piston slap the cylinder was not out of round and I only had to go half a mil over on it so I would like to keep from having to rebore it bigger.I have already added new crank seals as well as a complete engine gasket set from yamaha .I will be sure to post pics as I go and you guys can help with suggestions as I go! Thanks for your input Sir..I might also try to run it with the solid skirt piston and see how it acts, but I would like a opinion on weather or not it would hurt anything running it like that Im thinking it will just not have as much torque but to me these bikes already have alot of torque so it may be ok??...
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