Old LT80 won't turn over
#14
That's comforting. Thank you for the reply. So, just so I'm sure I understand:
Find my current piston size
Purchase next size up
Bore out cylinder to fit
Put new piston kit in and I should be good to go?
Find my current piston size
Purchase next size up
Bore out cylinder to fit
Put new piston kit in and I should be good to go?
#15
A new piston/rings should have you up and running in no time,looks like that little fella in your avitar is waiting for a ride !!! Just listen to Jack (LT80) and you can't go wrong, he'll help you get that quad up and running.
#16
Ok so I'm feeling a bit stupid. I was trying to remove the aluminum piece on the tranny that keeps the belt on and broke that, think a metal shop in town has the right welding gear for this though.
I've finally uncovered the root of the low compression after putting it aside for awhile. I removed the cylinder and noticed some deep scoring on one side of the wall under the porting. There's a little above the ports on the same side but it's barely deep enough to feel with a finger, the piston head is also scored on the same side under the rings. I was hoping for something a bit cheaper to fix honestly, but the quad was free so I can't complain much. Any ideas...please?
BTW Measurements:
I took these with my dial calipers (good ones) gauged to +-.001"
Cylinder wall:
Bottom 1.966"-1.968"
Top above ports 1.968"
Piston head:
Bottom (above crosspin) 1.955"-1.958"
Top above rings 1.950"
These were taken rather quickly and without removing the piston itsself from the arm/crank. Hope this info is useful. If you'd like pics I can get them.
I've finally uncovered the root of the low compression after putting it aside for awhile. I removed the cylinder and noticed some deep scoring on one side of the wall under the porting. There's a little above the ports on the same side but it's barely deep enough to feel with a finger, the piston head is also scored on the same side under the rings. I was hoping for something a bit cheaper to fix honestly, but the quad was free so I can't complain much. Any ideas...please?
BTW Measurements:
I took these with my dial calipers (good ones) gauged to +-.001"
Cylinder wall:
Bottom 1.966"-1.968"
Top above ports 1.968"
Piston head:
Bottom (above crosspin) 1.955"-1.958"
Top above rings 1.950"
These were taken rather quickly and without removing the piston itsself from the arm/crank. Hope this info is useful. If you'd like pics I can get them.
#17
"Ok so I'm feeling a bit stupid. I was trying to remove the aluminum piece on the tranny that keeps the belt on and broke that, think a metal shop in town has the right welding gear for this though."
You just cost yourself about 90 bucks. I doubt they can weld it and have it last.
And all you wanted to buy is rings. If things were that easy eh. LOL
Best wishes on your travels. (refering to your PM).
You just cost yourself about 90 bucks. I doubt they can weld it and have it last.
And all you wanted to buy is rings. If things were that easy eh. LOL

Best wishes on your travels. (refering to your PM).
#18
Ok. I found a guy in town who just happened to have a new Weseco stock size piston and rings in the box he sold me for $25. I got the piston on the arm (which is still in the engine) bit now to my next problem.
How the heck do I get the cylinder on and the piston in through the bottom of it? I can't figure this one out and I'm pretty sure hammers and brute force aren't the answer, lol.
BTW I had to use the old knuckle to hold the piston on because the new one wouldn't fit in the piston hole without a hammer. Fits good though I can't get one of the circlips that holds it in all the way into the groove so it's in as good as I can get it without taking it out and shaving some off of the knuckle.
Will be posting in the wanted section for a used aluminum plate thing for the tranny.
How the heck do I get the cylinder on and the piston in through the bottom of it? I can't figure this one out and I'm pretty sure hammers and brute force aren't the answer, lol. BTW I had to use the old knuckle to hold the piston on because the new one wouldn't fit in the piston hole without a hammer. Fits good though I can't get one of the circlips that holds it in all the way into the groove so it's in as good as I can get it without taking it out and shaving some off of the knuckle.

Will be posting in the wanted section for a used aluminum plate thing for the tranny.
#19
First off, do you have the rings in correctly. They only go on one way. On the ring end there is a letter ("N" or "T"). That's the top of the ring.
You got a hone and honed the cylinder? You should at least do that.
The knuckle is a piston pin and you don't have something right as both cir clips will go in place correctly. The way you have the cir clip, it will come out and cost you plenty. Get it in there correctly. You do not need to grind the end of the pin.
After all that, You get the ring gaps to where they belong (there is a pin in the ring groove) and compress the rings in and slide into the cylinder.
Use 2 cycle oil to coat the piston and cylinder for installation.
115 inch pounds on the head nuts.
"aluminum plate thing for the tranny." <--What's that?
You got a hone and honed the cylinder? You should at least do that.
The knuckle is a piston pin and you don't have something right as both cir clips will go in place correctly. The way you have the cir clip, it will come out and cost you plenty. Get it in there correctly. You do not need to grind the end of the pin.
After all that, You get the ring gaps to where they belong (there is a pin in the ring groove) and compress the rings in and slide into the cylinder.
Use 2 cycle oil to coat the piston and cylinder for installation.
115 inch pounds on the head nuts.
"aluminum plate thing for the tranny." <--What's that?
#20
I think it's called the 'Fixed Drive Face' per the exp parts view for the transmission. The $85 part that I broke. The rings were already on the piston in the box but I'll take 'em off and check. Diddn't know about any of that, thanks for the help. The cylinder is the old one and no it has not been honed after I took out the old piston. I did rub down the piston with 2stroke oil and the cylinder as well. Thanks again.




