After reading the post about the Lt80 topend and about someone putting the piston in backwards, guess what?

Yup I did it too! My head must've been way up there. My only question now is with the scoring on the cylinder. My son got about 10 minutes of very easy riding around the yard on his new piston and then I heard that distinct sound. But after he stopped it would still turn over. So we pushed it back and I took the top end back off. The rings are very tight on the piston but I'm gonna need another piston too I think. The piston is scarred pretty good.

Now in the other post Lt80 I believe mentioned there would probably be scoring off the exhaust ports. Now on mine if you lay the cylinder down with the exhaust port at the 12 o'clock position the scoring on ours is at 5 and 7 o'clock.

Anyone have any ideas?

 

Weisco or zuki piston?

 

weisco

 

Yup, That's where they squeze. [img]i/expressions/face-icon-small-sad.gif[/img]
Sand the piston agressively where the scratches are and carefully sand the cylinder if there is any aluminum on it. Put it back together and run it.
If your cylinder bore is still small enough to run a zuki piston,get one. They are much better.

 

So you think I can sand the piston, rering it and run it if the cyclinder is still in spec. How aggressively do I want to go with sanding the piston? Such as what grit? The piston is scarred pretty decent but I figure if I can get is smoothe along with the cylinder, with new rings I should be OK on compression?

Also I'm not sure on the zuk pistons. I'm at a .20 bore now with the wiseco, but what sizes do the zuk's come in?

Thanks Jack!

 

Sand the bageezes out of it (up and down not side to side). [img]i/expressions/face-icon-small-smile.gif[/img] 80 grit or so.
Zuki pistons come in .5 and 1.0 over (.020 and .040)

 

jack check your email thanks kevin.

 

no luck! Cleaned the piston up nicely and tried it but no luck. I think the exhaust donut may need to be replaced. I know you need a certain psi to get it started and I'm only coming up with 70. Gotta check a few other things.

 

Anyone have experience with the Pro X piston? They're made in Japan and came highly recommended by CT racing over the Wiseco. I recently installed mine (51mm) with the rings upside down. I ran it for a little while and even after correcting them to right side up (thanks to Jack aka LT80 for catching that blunder) it seems to run with a lot of power. Anyone know what the dispacement is with a cylinder bored for a 51mm piston?

 

51mm= 85.798cc's

The majority of the worlds pistons are made by "artz" or "arts",,something like that. They make most all the stock factory pistons along with the pro-x stuff.

I wonder why CT puts a Weisco in their kit (that's what the ad says).