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Discussion Starter · #1 ·
on sunday about 50 miles out of christmas mi my motor locked up. PTO side.

got it home and tore it down and found the ring had broke and took a big hunk of piston with it.

here is my question.... do i have to bore both? or just the one that needs it?

thanks
gene
 

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genesly said:
on sunday about 50 miles out of christmas mi my motor locked up. PTO side.

got it home and tore it down and found the ring had broke and took a big hunk of piston with it.

here is my question.... do i have to bore both? or just the one that needs it?

thanks
gene
[snapback]287504[/snapback]​
Gene,
To answer your question honestly, it the other side isn't "broke" you don't have to fix it. Now for the logical answer. Re-work both sides at the same time. There could be damage you can't actually see. Also, as you know pistons work in unison, so boring one side and not the other is going to throw the balance of the engine off, and you'll end up with more problems. Taking your time and doing it right will provide you a more reliable machine, and lots less frustration.
 

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Discussion Starter · #6 ·
mbret2004 said:
genesly said:
on sunday about 50 miles out of christmas mi my motor locked up. PTO side.

got it home and tore it down and found the ring had broke and took a big hunk of piston with it.

here is my question.... do i have to bore both? or just the one that needs it?

thanks
gene
[snapback]287504[/snapback]​
Gene,
To answer your question honestly, it the other side isn't "broke" you don't have to fix it. Now for the logical answer. Re-work both sides at the same time. There could be damage you can't actually see. Also, as you know pistons work in unison, so boring one side and not the other is going to throw the balance of the engine off, and you'll end up with more problems. Taking your time and doing it right will provide you a more reliable machine, and lots less frustration.

[snapback]287566[/snapback]​
Thanks! I thought this to be the case but had to make sure... any ideas what in the world happend here? I had one guy in Autrain say that it was probley ice that caused it to lock up. My experince with 2 stokes are in dirt bikes and when they lock up it is normaly due to running too lean... sucking air from some where. In my case with this sled the ring was broke off ring in front of the exsaust port and it took some of the piston with it. the piston does show sighs of skuff on all sides but the side with the broken/missing ring is the worse.

Thanks for your help.

Gene
 

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I am a little late in a explanation for this post but better now. To answer the question of bore both holes. Yes you should if there is damage. To bore is to remove material making the hole bigger. To hone is to remove the glazing from the cylinder wall allowing new rings to seat.

Now think of it this way, big engine to small engine. Mind you are talking about 1 engine. Bigger makes more power then the small one.(in most cases) Now with this said the small one has to work harder to keep up causing more heat and stress. This will also cause the engine to run rough being that it is not matched to one another(out of balanced) One fresh side to a dead old side.

The case of ring failure like this is sometimes caused be the endgap not being enough. What happens is after the ring starts to heat up it expands so far to close the gap and creates pressure making the ring to break in the weakest spot. IE. the biggest opening it finds first to relieve that pressure. Not knowing the mileage in the engine before this happed is harder to say this.
 

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Leave the good side, but replace both pistons so they are the same brand. I'm not sure about other piston manufactures, but Wiseco makes all of their piston sizes for a particular engine the same weight. This allows you to run different sized pistons in each cylinder. As far as displacement, one size up in one cylinder isn't going to throw off the balance. Many drag bike and ice racers have dramatically different piston sizes. I have over 1000 miles on my engine with one cylinder bored 20 over and the other 40 over. Don't bore if you don't have to so you have enough cylinder left for next time something happens. re-sleeving is expensive.
 

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Discussion Starter · #9 ·
MXZBULL said:
I am a little late in a explanation for this post but better now. To answer the question of bore both holes. Yes you should if there is damage. To bore is to remove material making the hole bigger. To hone is to remove the glazing from the cylinder wall allowing new rings to seat.

Now think of it this way, big engine to small engine. Mind you are talking about 1 engine. Bigger makes more power then the small one.(in most cases) Now with this said the small one has to work harder to keep up causing more heat and stress. This will also cause the engine to run rough being that it is not matched to one another(out of balanced) One fresh side to a dead old side.

The case of ring failure like this is sometimes caused be the endgap not being enough. What happens is after the ring starts to heat up it expands so far to close the gap and creates pressure making the ring to break in the weakest spot. IE. the biggest opening it finds first to relieve that pressure. Not knowing the mileage in the engine before this happed is harder to say this.
[snapback]287754[/snapback]​
the sled had 4k miles on it and i have never turned a wrench on it.

Thanks for all the help
gene
 
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