biglsells
VIP Member
Hello all, fist post.
Quick back story - bought a 1998 vmax 600sx for $200 from some guy in the country this summer, the right cyl was blown, piston ring pin failed and it chewed them up, the sled it otherwise beautiful.
The jug was junk so I bought a used one locally, bought two new piston & ring kits, new top end gasket kit, rebuilt it, cleaned carbs, fired right up, 142psi on both jugs.
Took it out today for my first ride on it as we just got snow here. Made it 2.5 miles and the engine just bogged and shut off. Started it back up, drove fine for about 20 seconds then the same thing, this time it felt rough when I pulled it over so I trailered it back home (I could hear some scraping sound from the LEFT jug when I pulled it over). Took the heads off and left jug off, the piston was melted along the intake side, luckily the cylinder looks fine just have to clean it a bit. My question - what would have caused this? I can fix the piston/ring but dont want this to keep happening.
When I bought this the guy said he was just tired of 2 strokes so I am thinking he was not able to figure out what the problem was. If you look at the pics one is a pic of the bad piston and bad head so you can see coloration, one is of the good piston and head, the exhaust pipe shows that the side that failed is whiter than the side that is fine. Finally, when looking down into the engine on the bad side I thought it looked like it was cracked so I took the whole darn engine out but the case looks just fine from the outside so I am thinking its not cracked.
Oh - one more thing, when you look at the picture of the "bad head" you can see several dings from a ring that must have gotten chewed up before, this is not from today so he must have had these problems before.
What do I do? Any ideas?
I took pictures of the engine during disassembly - here they are
Quick back story - bought a 1998 vmax 600sx for $200 from some guy in the country this summer, the right cyl was blown, piston ring pin failed and it chewed them up, the sled it otherwise beautiful.
The jug was junk so I bought a used one locally, bought two new piston & ring kits, new top end gasket kit, rebuilt it, cleaned carbs, fired right up, 142psi on both jugs.
Took it out today for my first ride on it as we just got snow here. Made it 2.5 miles and the engine just bogged and shut off. Started it back up, drove fine for about 20 seconds then the same thing, this time it felt rough when I pulled it over so I trailered it back home (I could hear some scraping sound from the LEFT jug when I pulled it over). Took the heads off and left jug off, the piston was melted along the intake side, luckily the cylinder looks fine just have to clean it a bit. My question - what would have caused this? I can fix the piston/ring but dont want this to keep happening.
When I bought this the guy said he was just tired of 2 strokes so I am thinking he was not able to figure out what the problem was. If you look at the pics one is a pic of the bad piston and bad head so you can see coloration, one is of the good piston and head, the exhaust pipe shows that the side that failed is whiter than the side that is fine. Finally, when looking down into the engine on the bad side I thought it looked like it was cracked so I took the whole darn engine out but the case looks just fine from the outside so I am thinking its not cracked.
Oh - one more thing, when you look at the picture of the "bad head" you can see several dings from a ring that must have gotten chewed up before, this is not from today so he must have had these problems before.
What do I do? Any ideas?
I took pictures of the engine during disassembly - here they are