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Need to rebuild again


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Have around 10-15 hours on it since my recent top end rebuild, ported cylinders and wiseco pro lites.

Did a proper initial break in, and still haven

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Removed the cylinders today...couldn

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...and the cylinders

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Wow that sucks. I dont know what would have caused that.

 

When I was breakin in my top end I had the same thing happen. Took it easy for a tank. I took it out on the rode and wound it up. First time I really hit the power band on my drag port. Went through a couple gears and let off the throttle and the rear tires locked up, and slid on the gravel. I leaned back and snaped the clutch a couple times to break it free. It Idled real slow so I let it cool down. Fired it up and rode it around a little while taking it easy. I never had any other problems with it.

 

Fast forward 6 tanks of fuel. I was trail riding and I started getting a high lingering Idle. The cylinders came loose and blew the base gaskets out. I shut it down right a way when it wasnt idling right. I took it home and pulled the cylinders off just to replace the blown out gaskets. I found this.

 

That damage had to occure when it locked up on me. I had the pistons coated by swain tech. PC9 Dry Film lubercation coating on the skirts and thermal heat barrier on the piston heads, and domes. The PC9 saved my cylinders. There was just a tiny spec of aluminum that transfered and stuck to the cylinder wall. I think it would have looked like yours if I didnt have the pistons coated. It saved me and was worth it.

 

The pistons were a little tight when I put the engine together and that is what caused the siez. How was the clearance on yours?

 

Here is the pics of the carnage. You can see it smeared the coating but it didnt allow it to become as bad as yours.

 

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they look pretty much the same!

what does 'high lingering Idle' means? If the cylinders came loose they must have sucked in air from under the base leaning out the mixture.

Right before my seize I felt a type of higher idle when I pulled the clutch in while slowing down a couple of times from WOT...But my cylinders were totally tight, no lose nuts or bad gaskets. Maybe mine sucked in air from when the idle screw was missing.

Did you have your stock carbs or the 33mms on when it happened?

Regarding my clearence...I don

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yea by high idling it was a lean condition because it was sucking air. As soon as it happened I shut it down. I wouldnt have found the damage if it didnt happen.

 

I did have my PWK33's when it happend. I the damage had to happen when it locked up on me. I went for the first wot blast down a grave county rode. I only went through 4 gears. I let off to decelerate and it instantly locked the rear tires. The pistons were a little tight twards the bottom of the bore when I put it together. I just checked the clearance with a feeler gauge between the piston skirt and cylinder wall.

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Pretty interesting pics there. Def make sure you do a leakdown test when you put the motor back together and I would check the water pump impeller and gear especially if it is the stock plastic impeller to make sure it isn't burnt up and your motor overheated causing the damage.

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