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Posted

hey guys. well today i went to work on the shee. the left side had compression of 75 and the right side had compression 0f 3 :whoa: so we pulled the jugs off and the ring on my right piston just totally demolshed the piston and the wall and a bit of the exhast port. i cant even pull the bottom ring out because of the other ring just mashed all the metal around it and its stuck in there. so im taking my jugs to my mechanic for boring and im going to see if he can port them for me. I have 2 pics of my piston

http://www.tinypic.com/view/?pic=8xt26c

http://www.tinypic.com/view/?pic=8xt2e8

sorry bout the crappy quality

i guess what could of happened is my ring might of got stuck in my exhaust port and then it just screwed it up. it was right where the ring seperates so i duno. what do you guys think happened? also how do i get dirt out of where my crank is?

thanks guys

BFS

Posted

i guess what could of happened is my ring might of got stuck in my exhaust port and then it just screwed it up. it was right where the ring seperates so i duno. what do you guys think happened?

393077[/snapback]

Some better pics would help!

 

If you mean 'end gaps' when you say "where the ring seperates ...", then your piston was in the cylinder facing the wrong way and you possibly caught a ring on the exhaust port. ... The end gaps should be on the intake side of the cylinder.

 

With 75 psi on the other cylinder, I'm surprised the bike ran. ... You were certainly overdue a topend rebuild.

 

Rare.

Posted

It depends on how many hours where on that top end. It could of failed because they were just wornout. As far as the port job goes I would research who you take them to there is a huge differance in a average port job and a great port job. As far a I am conserned porting cylinders is an art form take it to some that knows how to do it.

Posted
piston was in the right way. dont the end gaps have to be opposite of eachother?

also if it says .50mm on top of the piston what does that mean?

 

393176[/snapback]

If it was in the right way, then the arrow on the top of the piston would be pointing towards the exhaust.

 

The end gaps of the rings are both on the intake side, but the pins to stop them moving are about 1 1/4 inches apart. (On a Wiseco Prolite). ... Does it look like the wear of the piston/rings/bore has allowed the ring to slip over the pin and spin around the piston?

 

The .50mm on the top means the pistons are 1/2 mm oversize (0.020").

 

Rare.

Posted (edited)

i dont think it will run if the piston is in backwards. :huh: cause then the port windows would face the ex port.

 

on porting, im with switchblade. anyone can hack into a jug but to see gains with out reducing the wear on your rings is a different story.

 

EDIT : WHOOPS

Edited by gimmeabeer
Posted

ya i know i wont go any further then i have to. i wont be the one boring my mechanic will. as far as my exhaust port on the right side where the piston came from the exhaust port is like rougher then the left side from that broken ring so do I need a new jug or will that affect anything

Posted
... so do I need a new jug or will that affect anything

393339[/snapback]

That's what your 'mechanic' will be able to decide. ... Is the damage in the roof of the exhaust port or the floor?

 

If it's in the roof, then the porting that you say you are going to get done will raise the exhaust higher by a couple of mm (going by your style of riding) and take away the damage if it's only slight. ... Someone that knows what they're doing needs to physically look at your barrells, there's no other way.

 

Rare.

Posted
ya i know i wont go any further then i have to. i wont be the one boring my mechanic will. as far as my exhaust port on the right side where the piston came from the exhaust port is like rougher then the left side from that broken ring so do I need a new jug or will that affect anything

393339[/snapback]

If it isnt that bad, maybe try to polish both sides up. It really should mess with you unless it is really bad. Make sure you take it to a good, trust worthy mechanic becasue you are in prime position to get screwed.

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