Piston replacement

JDavis

New member
Joined
Jan 4, 2011
Messages
2
Age
56
Location
Rimbey,AB
Hi there,
I could use some advice in fixing my sled as I'm quite new to the sledding world. I have a '96 Mnt Max twin 600 and I burned a piston ( flywheel side). The head is pitted and the cylinder is scored quite bad just above the exhaust port and the piston is melted. Does anyone have any recommendations on what brand of parts I should be using? I thought genuine Yamaha for the cylinder then maybe a higher quality piston. My plans are to replace both pistons to keep my crank balanced perfectly ( dumb idea?). Also, any ideas as to why this would have happened on just one as the other piston looks great. The sled only has 1800Km on it. Thanks in advance.
P.S also has smart carbs
 

JDavis said:
Hi there,
I could use some advice in fixing my sled as I'm quite new to the sledding world. I have a '96 Mnt Max twin 600 and I burned a piston ( flywheel side). The head is pitted and the cylinder is scored quite bad just above the exhaust port and the piston is melted. Does anyone have any recommendations on what brand of parts I should be using? I thought genuine Yamaha for the cylinder then maybe a higher quality piston. My plans are to replace both pistons to keep my crank balanced perfectly ( dumb idea?). Also, any ideas as to why this would have happened on just one as the other piston looks great. The sled only has 1800Km on it. Thanks in advance.
P.S also has smart carbs

Run an OEM piston or a set of SPI's. Its hard to beat the OEM pistons. They are tough! It make since to replace both of them. Its self assuring to me. JMHO

The reason why the piston melted, is because its running lean on the Mag side of the house. I would double check the carbs. Might be to small of a main jet, needle not in the right position (clipped on the 1st position) and so on!

http://cgi.ebay.com/ebaymotors/1999..._Accessories&hash=item58899853ef#ht_976wt_728
 
I agree with going with stock Yamaha pistons. In this case I would change the one piston but replace the rings on both. Unless you can justify replacing a good piston I don’t see the need.

Just my two cents.
 


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