400 pistons

[Mike Lenz]

I have a 55 30 007 700 82mm ELKO piston that has very thin skirt walls. Quite abit thinner than most other pistons I've seen. What gives, anybody seen this before? Im wondering hoe long the thing will work before the skirt collapes some???

 

[Dr.2Stroke]

Guess youre having a factory(special series) piston! Were made for world championchip drivers like Willy Bauer or so.are not as durable as the original pistons,but there could be a little more punch and bite in the higher range! compare the overflow channels of the cylinder,where the piston was built in with another 400 cylinder. could be different!

 

[Mike Lenz]

This is a new piston so dont have a cyl it matched up with. Since your so knowledgable,I also have another 82mm Elko piston in a 55 30 007 608 box that is very heavy duty, and very heavy by weight that appears to be a cast piston??!!

 

[Dr.2Stroke]

Check the number on the bottom of the piston,and measure the thickness of the skirt. Could be also from a 390 from 82. KTM replaced the 550 30 ... pistons by the 562 30 .. pistons. They still have only one ring!

 

[Mike Lenz]

Looking at again it is a cast TWO ring piston. The skirt is about an eighth of an inch thick with a ridge another eighth inch thick near the bottom of the skirt. There are two sets of numbers on the inside of the skirt. 2E81 and 37/2. Pretty strange isnt it. Also 1405/4 is stamped on top of the piston.

 

[Mike Lenz]

I have another question I would like to get settled here too if I can. Whats better one ring or two? I realize one is less drag. But for anything other than maybe a 125 does this really make much of a differance? Do two rings last longer before losing the same amount of compression? Please no biased answers here do to the fact someone answering may have one or the other to sell, I want the truth the whole truth and nothing but the truth here. Thanks