Bike is an 07 144SX. Motor was freshly rebuilt.....first ride. Coolant bleed bolt located in cylinder head was not secured properly. All fluid pumped out of motor and piston seized. Pulled top end to find trashed piston and some scoring within the cylinder; below the transfer and exhaust ports. Reassembled top end with new piston. Motor seems to run fine but don't know for sure what the impact of the cylinder scoring in this location would be. The cylinder looks fine above the exhaust port. Would there be a performance impact if the ring seal below the ports is not perfect?
Cylinder scoring affect; below ports
- Thread starter MXTex
- Start date
MXTex said:
YES. Ring seal is critical to performance. Did you have the cylinder honed before you assembled it with the new parts?
CarnageZ28
Member
- Mar 25, 2008
- 109
- 0
Yes because as the piston goes below the ports, it is putting pressure on the crankcase and helping to draw the air/fuel mixture into the cylinder via the ports. While it likely would not make a drastic difference in performance, it certainly isnt helping it.
Pics of the score by chance?
I think it would be most noticable when starting the bike/low RPM's.
Pics of the score by chance?
I think it would be most noticable when starting the bike/low RPM's.
CarnageZ28 said:
It's likely to be the least noticeable at those points because the cylinder pressure is at it's lowest.
CarnageZ28
Member
- Mar 25, 2008
- 109
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See I thought it would be most noticable, because the piston speed/pressure is so much slower/lower than it would take less of a pressure drop to make a noticable difference in power than it would at high RPM's ...
Still though, I see where your coming from and it makes sense. And there is no argueing you know quite a bit about 2-strokes.
Still though, I see where your coming from and it makes sense. And there is no argueing you know quite a bit about 2-strokes.
I would figure its science Carnage, not figuring.
CarnageZ28
Member
- Mar 25, 2008
- 109
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Well regaurdless what it is, it doesnt seem to be effecting his performance as the bike runs fine. Maybe it is far enough below the port that the ring never touches it?
Hopefully...
Hopefully...
helio lucas
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- Jun 20, 2007
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the ring may never touch it but the piston skirt yes... and that should make the piston wear faster or even break, depending on the severity and if it´s been honed...
could you post some pics?
could you post some pics?
Right on Helio, good bye piston skirt! When the piston is rocking, I would not ride it.
CarnageZ28
Member
- Mar 25, 2008
- 109
- 0
Yep totally possible.
I think if it was high enough his rings were going over it that he would have had power issues/running hot, etc.
It may be small enough that the piston touching it has no effect.
If you generally take it easy on the bike, I would tear it down every 5-10 hours and see how it looks. If its showing any signs of odd wear, send it out, have it bored and plated, or welded and plated.
You dont want to roast a good engine over something thats a (relatively speaking) cheap fix now.
I think if it was high enough his rings were going over it that he would have had power issues/running hot, etc.
It may be small enough that the piston touching it has no effect.
If you generally take it easy on the bike, I would tear it down every 5-10 hours and see how it looks. If its showing any signs of odd wear, send it out, have it bored and plated, or welded and plated.
You dont want to roast a good engine over something thats a (relatively speaking) cheap fix now.
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