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Posted: Sat Feb 21, 2009 5:48 pm
by vmax-540
Question, is that the intake or exhaust side of the piston ?

Posted: Sun Feb 22, 2009 10:36 am
by 1987vmax
I am going to tear the bottom end down tommorow I will post some pics. I have since sent the mag cylinder back to the place I got it they are going to try & get me a new one

Posted: Sun Feb 22, 2009 11:49 am
by vmax-540
One other thing to check is the fuel pumps ,on the Vmax the mag side cylinder works the fuel pump for the pto carb and vise versa. You could have a bad or weak pump I had that happen to a friends sled about 10 years ago. Not saying it is it but something else to check .

Posted: Sun Feb 22, 2009 12:44 pm
by 1987vmax
I had intentions of taking both fuel pumps off & checking them I also wanna paint the engine compartment so basically everything is getting a going over.

Posted: Sun Feb 22, 2009 1:53 pm
by sxr1000
here is a pic of a piston that had the crank bearing go out.
Image

Posted: Mon Feb 23, 2009 2:29 am
by Joe
My OPINION of what happened is this:

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Broken rod bearing debris entered the combustion chamber through the transfer ports.

Debris got caught between the piston and the top of the exhaust port breaking the top ring land and pinching the upper ring.

The upper ring failed near the exhaust port.

The ring caught in the exhaust port and broke the land between the upper and lower ring grooves on the exhaust side of the engine.

The debris from the shattered piston and ring got smashed between the piston and squish area of the head until the debris went out the exhaust port.

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I would suggest removing the exhaust and inspect any metal pieces that you find.

Piston land is alumunum.
Rod needle bearing is cylndrical steel.
Piston ring is recangular steel.

My OPINION is that some (but not all) of the dents in the top of the piston were made by cylindrical debris indicating that a rod bearing failed.

Posted: Mon Feb 23, 2009 6:04 pm
by 1987vmax
I dissambled the bottom end today everything with the crank looks fine all main bearings spin really good no noise at all & the rods look really good aswell I am going to take more pics to show you guys.

Posted: Thu Feb 26, 2009 10:46 pm
by 1987vmax
Image

Image

Image

Posted: Thu Feb 26, 2009 10:50 pm
by 1987vmax
Image

Posted: Fri Feb 27, 2009 4:41 am
by Joe
Is that metalic debris in the crankcase bottom?
Is it magnetic or non magnetic?

Posted: Sun Mar 01, 2009 11:38 am
by sxr1000
Man that sure looks like bearing debris to me,could it have come from the gearcase and somehow got past the seal?

Posted: Sun Mar 01, 2009 11:08 pm
by jipcee
See where the white part on the seal is and part off the seal is missing, I would say that is the culprit right there (sucking air leaned it out)
From the looks of the head the left (PTO) side is running WAY rich.
Also that head is junk unless you get it machined.
Image

Posted: Mon Mar 02, 2009 10:03 pm
by 1987vmax
I have a friend that I apprenticing under a while ago he remembers these machines like it was yesterday.I showed him the parts & he thinks someone machined the head & it wasn't true he said the pattern on the crown of the piston is not even & ran hot because of too much comression.the head i had on there i got from ebay & that motor was ported so if anybody wants to buy a set of ported jugs let me know I will keep you posted

Posted: Tue Apr 21, 2009 1:54 pm
by 1987vmax
I have recently assembeled the engine the previous head had been shaved down & had alot of combustion chamber work done to it.Hopefully everything works out next winter.The other thing I wanted to ask was about the side panels is the original paint gloss black or meduim black I want to restore it. thanks

Posted: Thu Apr 23, 2009 12:09 pm
by Vmax540
I'd say more of a meduim black ?