electrode now touching tip!

[gsxr800]

After putting in a new sbt motor in my 98 gsx limited in may of 2007 everything ran great all season. Started it up and ran it yesterday on the river for about 1/2 hour it ran great! then squeezed the throttle to catch up to my buddy and the motor started to stumble and loose power so i got off the throttle and shut it down right away. Not sure what had gone on i tried to restart and it ran like crap so i just shut it off and towed it in. Got it home and pulled the plugs and found the pto side plug had the electrode touching the tip of the spark plug! Also the normal wetness around the plug along with a silvery colored substance and some small debris in the empty areas of the plug. Does anybody know what may have happened? I purchased the motor on May 9th of 2007. Do you think it can still be covered under warranty?

[skisol]

Re: electrode now touching tip!

After putting in a new sbt motor in my 98 gsx limited in may of 2007 everything ran great all season. Started it up and ran it yesterday on the river for about 1/2 hour it ran great! then squeezed the throttle to catch up to my buddy and the motor started to stumble and loose power so i got off the throttle and shut it down right away. Not sure what had gone on i tried to restart and it ran like crap so i just shut it off and towed it in. Got it home and pulled the plugs and found the pto side plug had the electrode touching the tip of the spark plug! Also the normal wetness around the plug along with a silvery colored substance and some small debris in the empty areas of the plug. Does anybody know what may have happened? I took this picture with my camera phone so it sucks but i will get a better one to post. I purchased the motor on May 9th of 2007. Do you think it can still be covered under warranty?

99% when you find a sparkplug like this it means:
Engine failure!
No way of telling what failed untill the engine comes apart.

[gsxr800]

Re: electrode now touching tip!

here are better pictures of the plug.

[skisol]

Re: electrode now touching tip!

Still engine failure and seems like melted piston due to lean condition, could be carb issue or crank case leak.
You still need to split the engine to find out what caused the engine to fail, it is important to know before you install a new SB, it might happen to your next one again if the damage has been done by something that you will use in your next setup.

[gsxr800]

Re: electrode now touching tip!

So I took off the cylinder head to inspect the damage and found the upper ring broken and a chunk of the piston gone. So correct me if I'm wrong but this does not look like a lean condition issue. This looks like a piston or ring failure. Here are some pics. The first pic is looking threw the rave opening.

[gsxr800]

Re: electrode now touching tip!

Still engine failure and seems like melted piston due to lean condition, could be carb issue or crank case leak.
You still need to split the engine to find out what caused the engine to fail, it is important to know before you install a new SB, it might happen to your next one again if the damage has been done by something that you will use in your next setup.

But if this was a lean condition shouldn't the cylinder walls be marked up with scratches and gouges? Its still smooth.

[dsolie]

Re: electrode now touching tip!

It could have been lean.. That spot where the ring is exposed isn't a snag, that's a MELT, caused by excessive heat, possibly by deto starting the damage, and combustion finishing off the top end.

The best way you can tell if it's heat is to look at the rod, if it's discolored, then it got WAY too hot.

I have never seen a piston with that much melted material on it.. That sucker was warm I bet.

[skisol]

Re: electrode now touching tip!

But if this was a lean condition shouldn't the cylinder walls be marked up with scratches and gouges? Its still smooth.

If that melted part of the piston is at the side of the exhaust poort which it looks like you had a lean condition.
Next step is to find the cause.

[gsxr800]

Re: electrode now touching tip!

It could have been lean.. That spot where the ring is exposed isn't a snag, that's a MELT, caused by excessive heat, possibly by deto starting the damage, and combustion finishing off the top end.

The best way you can tell if it's heat is to look at the rod, if it's discolored, then it got WAY too hot.

I have never seen a piston with that much melted material on it.. That sucker was warm I bet.

Also about 2 weeks ago I had to pull the pipe out to fix some stripped threads on the cone support location and while having the exhaust manifold off I was able to inspect the pistons. The same side the damage was done to had a small mark in the edge of the piston in the same location. The mark looked like a virtical notch about the size of a hacksaw blade right at the edge of the piston above the ring. Could this have led to the problem?

[skisol]

Re: electrode now touching tip!

I was able to inspect the pistons. The same side the damage was done to had a small mark in the edge of the piston in the same location. The mark looked like a virtical notch about the size of a hacksaw blade right at the edge of the piston above the ring. Could this have led to the problem?

There is no telling for us if we don't see it, what I don't understand is that if you inspect pistons, see something unusual that you put it back together and run it like all is good.
Something might have been going on and could have been stopped and protected you from your engine failure.
Who knows?

[dsolie]

Re: electrode now touching tip!

The vertical groove could have very well been the beginning of the failure. Depending on the groove, and the amount of heat it allowed to reach in there...

If the groove had any raised edges on the crown of the piston, then that would have created a combustion hot spot, which would have melted, and the rest is history.. Would have happened in a matter of minutes/seconds too.

[gsxr800]

Re: electrode now touching tip!

How would I go about cleaning the head cover? I will be purchasing the top end exchange kit and I don't think it comes with a new head cover.

[Technical Support]

Re: electrode now touching tip!

You need to go through the carbs and check the internal fuel filters, That melt down is due to lack of fuel. If you have the old gray fuel lines on the ski you should replace them. If it was an air leak there would be major scoring around the piston and cylinder wall. Tom SBT tech.

[gsxr800]

Re: electrode now touching tip!

last year i rebuilt the carbs including fuel filters. changed out the needles and seats and put in bill o'niels jet kit with flame arrestors and outerwares. Replaced all fuel lines. Confused as to what happened. I will take the motor out this week to inspect the rest of it.

[gsxr800]

I need to know why i melted the piston!

I took apart the carbs and the fuel filters were clean. What else could cause the pto side piston to run lean?