brnleva
New member
Hears the situation. Just bought two beautiful 2002 vmax's 700 and a 600 the 700 has about 5k on it the 600 3,500 miles on it I just cleaned the carbs on the 600 we took it up north and rode probably 40 miles then the next morning it was probably 3 degrees we were about 6 miles in and my son asked me to try it thought it wasn't quite right I was getting on it pretty good didn't feel to bad just died after checking it determined that the pull start side cylinder lost compression we towed it back and only started it to put it on the trailer but I had noticed a knocking sound which is making me sick to my stomach I haven't taking it apart yet will theses motors make that noise when they have a dead cylinder or am I looking at a catastrophic engine failure?
shaggyzr2
Active member
Does it knock at any rpm?
brnleva
New member
Well I haven't run it that long because I'm afraid of the noise and it doesn't want to idle but it did seem to increase with the rpm's of the engine
shaggyzr2
Active member
If you have a probe light you can shine it down through the plug hole, you can usually see if there is any damage to piston and cylinder.
brnleva
New member
I have a borescope at work I may go get it look now.... Do these engines have bottom end issues
shaggyzr2
Active member
You can also pull the carbs and the reed cages and look down inside at the crank with your scope. Those are usually pretty strong bottom ends.
brnleva
New member
Well I just looked down through the plug hole I can see the end of one of the rings its out and bent until I pull the jug I guess I just won't know...
Sounds like a ring started to spin and caught one of the exhaust/intake ports, was the motor recently rebuilt?
Lil' Mtndreamer
New member
Could be crank needle bearing that connects the piston rod to crank, my bottom end is ruined because that happened to me... it could be something else too.
Solid engines - one of the best of it's era. I would carefully look for the root cause as you tear it down. They are very easy to rebuild, just make sure you find the cause or history can repeat itself. As long as debris did not mess up the crank bearings it shouldn't run into too much money, especially if you do it yourself. Lot's of info on this site in old posts as well as the Tech Pages.
roudyroy1
Active member
I had a ring catch on the exhaust bridge on my yz and it took a massive chunk out of the piston and mashed the top end. had to get the jug redone but just flushed the crank out and it was good to go. I also had the locating pin vibrate out, fall into the crank case, make its way up through the transfer port into the combustion chamber and get pressed through the piston and 2 rings on an outboard. i originally thought is was a needle bearing. take pictures when you take it apart, gotta find the source of the problem.